Sect-1

Section 1: System Description

Chapter 1 - Functional Description

1.1 System System overview ............................................ .................................................................. .......................................... .................... 1-1 1.2 7200 Series UPS ‘single-module’ configuration ...................................... ...................................... 1-2 1.2.1 Power rectifier & battery charging ........................................... .............................................. ... 1-2 1.2.2 Battery charging modes ............................................. ............................................................... .................. 1-3 1.2.3 Power inverter ........................................................... .............................................................................. ................... 1-4 1.2.4 Static Static switch assembly ................................................................. ................................................................. 1-5 1.3 UPS Power Switch Switch Configuration ........................................... ............................................................ ................. 1-6 1.3.1 Maintenance bypass supply ........................................ ......................................................... ................. 1-6 1.3.2 Static bypass bypass configuration .......................................................... .......................................................... 1-6 1.4 “1+1” Parallel-module Parallel-module system .......................................... ................................................................ ........................ 1-7 1.4.1 Redundant vs Non-Redundant Non-Redundant configuration ............................... ............................... 1-7 1.4.2 Inter-module power power rectifier control ............................................ ............................................ 1-8 1.4.3 Inter-module inverter control ....................................................... ....................................................... 1-8 1.4.4 Inter-module static switch control control ............................................. ............................................... .. 1-9 Chapter 2 - Main Power Circuit Diagram Descriptions

2.1 Chapter overview ........................................ ............................................................. ........................................... ...................... 1-11 2.2 30kVA 30kVA Model description description – SE-5410303-P SE-5410303-P .......................................... .......................................... 1-12 2.3 40kVA Model Model description – SE-5410304-Q .......................................... .......................................... 1-17 2.4 60kVA Model Model description – SE-5410308-U .......................................... .......................................... 1-22

S-1.fm5 - Issue 2 Dated 21/08/97

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SECTION 1 - Sy s t em Des c r i p t i o n

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7200 Ser i es UPS Ser v i c e Man u al

S-1.fm5 - Issue 2 Dated 21/08/97

Section 1:

Chapter 1 - Functional Description

1.1 1.1

System overvi ew A 7200 Series Uninterruptible Power Supply (UPS) system is designed to furnish a well regulated 3 phase power supply to a critical load, s uch as a computer, under all rated load and input supply conditions. Being of a category known as an ‘online’ UPS system, it is permanently connected between the utility 3-phase supply and the load equipment and operational at all times, as shown in Figure 1-1. 1-1. Figure 1-1: 1-1: UPS System connections Q1

Input Mains

Q4

Output to Load

7200 UPS Input Sw

Output Sw

SW-BAT

BATTERY

The UPS system offers the user the following advantages:

Increased power quality: The UPS has its own internal voltage and frequency regulator circuits which ensure that its output is mai ntained within close tolerances independent of voltage and frequency variations on the mains power lines.

Increased Increased noise rejection: By rectifying the input AC power to DC power, and then converting it back to AC, any electrical noise present on the input mains supply line is effectively isolated from the UPS output, therefore the critical load sees only clean power.

Power blackout blackout protection: If the mains power fails, the UPS continues to power the critical load from its back-up battery source, leaving the load immune from power disturbances – even complete power blackouts. This manual describes two types of system configuration; a single-module system, and a two-module parallel-operating system which is known as a “1+1” system. Note that the modules used in both system configurations are broadly identical, and it is possible to convert a “single-module” system to a “1+1” parallel-operating system with the addition of a second module and a degree of intermodule control and power wiring. This chapter continues by functionally describing a “single-module” UPS system followed by details of the changes and additions applicable to the “1+1” configuration. To understand the functional operation of a “1+1” system you should therefore first read the “single-module” description.

s1-c1.fm5 - Issue 2 Dated 21/08/97

1-1

SECTION 1 - System Description CHAPTER 1 - Funct ional Descrip tion

1.2

7200 Seri es UPS

7200 Series UPS Service Manual

‘single-module’ configu ration

The 7200 UPS comprises two major controlled power modules, the ‘rectifier’ and ‘inverter’, which together operate as an AC-DC-AC converter (See Figure 1-2) .

1.2.1

Power rectif ier & battery chargin g The first conversion stage (from AC to DC) uses a 3 phase, fully-controlled SCR bridge rectifier to convert the incoming mains supply into a regulated d.c. busbar which, when the input supply is present, powers the inverter section and also provides the battery with its continuous float charging voltage. The nominal d.c. busbar voltage (i.e. battery float voltage) depends on the number of cells forming the battery, which in turn varies according to the system’s nominal working voltage (See Table 1-1) . Also, a temperature-compensated battery charging regime is used to prolong battery life, and this w ill slightly affect the dc busbar (float) voltage produced by the rectifier – by reducing the charge voltage as the battery tem perature rises. Table 1-1: DC Bus voltage parameters Parameter

380V

400V

415V

192

198

204

Nominal battery float charge

432Vdc

446Vdc

459Vdc

Nominal battery boost charge

460Vdc

475Vdc

490Vdc

End of battery discharge

320Vdc

330Vdc

340Vdc

Absolute maximum (manual)

480Vdc

495Vdc

510Vdc

Number of battery cells

In the event of a mains power failure, the rectifier becomes inoperative and the inverter is powered solely from the battery, which obviously begins to discharge. Critical load power is thus maintained under these conditions until either the input mains is restored or the battery is fully discharged (See Table 1-1) – whereupon the UPS shuts down. The period for which the load can be maintained following a mains power failure is known as the system's ‘ Autonomy Time’ and is dependent upon both the battery A/Hr capacity and the applied percentage load. Figure 1-2: Block diagram of main power flow DC Busbar Q1

Input Mains

Q4 Rectifier

Output to Load

Inverter

Input Sw

Output Sw

SW-BAT

BATTERY

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1.2.2

SECTION 1 - System Description CHAPTER 1 - Functi onal Descript ion

Battery chargin g mod es The batteries are connected to the DC busbar via an external circuit breaker and the rectifier voltage can be controlled at three selected battery charge levels. These level are described as: • Float charge • Boost charge • Manual charge

Caution 1.2.2.1

Boost charge should not be used with valve-regulated (sealed-cell) batteries Float charg e

This is the normal mode of operation when using non-sealed cells and the ONLY permissible mode when using sealed-cells. In the ‘float charge’ mode the rectifier is set to operate at 2.27V/cell (2.23V/cell for Yuasa batteries) – calibrated by a potentiometer on the Rectifier Logic Board (See section 4 paragraph 2.3.2) . Battery current limit

A hall-effect DCCT fitted in the battery feeder monitors the charging current and drives a ‘current-limit’ circuit on the Rectifier Logic Board (See section 4 paragraph 2.3.4.1) which, when appropriate, restricts the charge current to a preset maximum level by reducing the DC busbar voltage. This is adjustable within the range 0–25% of the rectifier input current rating and is factory set at 15%. In practice, this circuit is only likely to come into operation when the mains supply is restored following a prolonged outage and the batt eries are heavily discharged. Under these circumstances you may observe a reduced DC busbar voltage when the mains initially return. As the batteries take on charge, and the charge current therefore reduces, the effects of the current limit control is gradually lifted and the busbar voltage increases to nominal. 1.2.2.2

Boo st charg e

If the ‘boost charge’ facility is enabled and the batteries undergo a heavy discharge during a mains outage, the Rectifier can automatically switch to its ‘boost charge’ mode of operation when the mains supply returns. This increases the DC busbar voltage to the preset boost charge level (See Table 1-1) . The resulting increase in battery charge current reduces the time taken by the batteries to regain their lost charge – in readiness for the next mains failure. The boost charge level is set on the Rectifier Logic Board (See section 4 paragraph 2.3.2) . Note: the battery current limit function is still active when ‘boost charge’ is invoked. Float/Boost changeover

If the ‘boost charge’ facility is enabled the rectifier does not necessarily adopt the ‘boost charge’ mode every time the mains supply returns from an outage; but is invoked only if the charge current exceeds a certain threshold (known as the “float/boost changeover threshold”) after a brief time has elapsed – i.e. if the charge current does not exceed the “float/boost changeover threshold” the rectifier will adopt, and remain in, its ‘float’ charge mode upon mains return. If the current does exceed the “float/boost changeover threshold” the rectifier will adopt the ‘boost mode’ until the batteries are sufficiently charged that their charge current falls below the “changeover threshold”, whereupon it will switch back to


1-3



it’s ‘float charge’ level. The time for which the batteries are subjected to the boost charge is therefore mainly dependant on the discharge level. Boost duration timer

If there is a fault on the battery string, such as several shorted cells, the resulting increased charge current could be sufficient to trigger off the boost mode irrespective of whether or not the batteries had been heavily discharged. Also, under such circumstances the charge current is unlikely to fall back below the float/boost threshold and the rectifier will continue to operate at its boost charge level indefinitely; which in turn could lead to yet further battery damage. To overcome such events, a timer in included in the float/boost changeover control logic which limits the duration for which the rectifier is allowed to operate in the boost charge mode. Although the rectifier ‘float’ and ‘boost’ charge voltages are set by variable resis tors located on the Rectifier Logic Board, the “changeover threshold” and “duration timer” are processor controlled and can be set from the UPS Control Panel. Note: it is also possible to invoke an immediate ‘boost charge’ manually from the UPS Control Panel (normally undertaken only during c ommissioning). 1.2.2.3

Manual charg e

When ‘manual charge’ is selected (from the UPS Control Panel) the rectifier (D.C. busbar) voltage is manually controlled by a potentiometer on the Rectifier Logic Board and can be adjusted from “zero” up to the rated “maximum” (See Table 1-1). In practice this facility is used as a means of controlling the rectifier during troubleshooting and can also be useful when applying the initial battery charge during commissioning (open vented cells only). When the rectifier is operating in the manual mode the inverter is automatically shut-down to prevent damage.

1.2.3

Power in vert er Embracing the latest IGBT switching technology, the inverter power section em ploys PWM control techniques to convert the dc busbar into an a.c. voltage which is then transformed up to the nominal system working voltage and fed to the load terminals via the output static switch. The purpose of the inverter is therefore to convert the wide-ranging D.C. busbar voltage (See Table 1-1) into a tightly controlled 3-phase 50H z sinusoidal output. The inverter control philosophy includes independent voltage regulation control of each of the output three phases, together with current limit and overload protection. The output frequency is digitally controlled and normally synchronised to the bypass supply – see description of the Static Switch operation below.

1-4



1.2.4


Static swit ch assembly Figure 1-3: Block diagram showing Static Bypass Q2 S S A P Y B

BYP-SS Bypass Sw

Static Switch

Q1 S N I A M

Rectifier Input Sw

Inverter

Q4

INV-SS Output Sw

Figure 1-3 shows a block diagram of the static switch and its relationship with the other UPS power blocks. As the diagram shows, the static switch comprises two areas: one (INV-SS) is connected between the inverter and output terminals and the other (BYP-SS) is connected between the output terminals and a switched 3 phase bypass supply line. The purpose of the static switch is to provide a means of transferring the load between the inverter and raw bypass supply in a controlled manner such that it ex periences no power-break when transferring from one to the other. Under normal circumstances the ‘inverter-side’ static switch (INV-SS) is closed and the load is powered from the inverter output; however in the event of an inverter fault, or overload which exceeds the inverter capability, t he ‘inverter-side’ static switch opens and the ‘bypass-side’ closes, in a make-before break fashion, and transfers the load to the 3-phase bypass supply. Conversely, when the inverter becomes available (or the overload condition c lears) the load is transferred back to the ‘inverter-side’ and the system continues its normal operation. In order for a ‘no-break’ transfer to take place the inverter frequency is normally synchronised to the bypass supply at all times – provided the bypass frequency remains within a specified frequency window. An ‘out of sync’ alarm annunciates if the inverter is unable to synchronise to the bypass supply due to an out-ofwindow condition or unstable bypass supply. This does not affect the normal UPS operation, in as much as the inverter frequency will remain within its prescribed limits, however if this condition is present when a transfer-to-bypass is requested then there will be a slight break (max 1 cycle) in the load supply while the transfer takes place – to protect the critical load from possible high voltage transients when switching between out-of-phase supplies. In practice, the ‘inverter-side’ static switch function is served by a contactor while the ‘bypass-side’ static switch comprises a pair of inverse-parallel connected SCRs in each bypass line (6 SCRs in total). The contactor coil and SCR gates are controlled by an interlocking circuit on a common control circuit board which prevents both sides of the static switch from being energised at the same time.


1-5


1.3


UPS Power Switch Confi gur ation Figure 1-4: Power Switch configuration Q3

Maint Bypass SW

Q2 S S A P Y B

BYP-SS Bypass Sw

Q1 S N I A M

Q4 Rectifier

Input Sw

1.3.1

Inverter

INV-SS Output Sw

Maintenance bypass sup ply An alternative hard-wired bypass supply is ‘made’ when Q3 is closed. This connects the UPS output terminals directly to the bypass supply and is designed to allow the load to be powered from the bypass while the remainder of the UPS is shut-down for maintenance or troubleshooting. If the UPS control logic detects that Q3 and Q4 are closed simultaneously, it will shut-down the inverter and open the ‘inverter-side’ static switch to prevent the UPS being damaged by reverse power flowing into the inverter output terminals from the maintenance bypass line.

Caution

1.3.2

The load is not protected against supply aberrations when connected to the bypass supply – either on Maintenance Bypass or when running on Static Bypass

Static bypass conf igu ration Figure 1-4 illustrates that links are connected between the bypass supply terminals and UPS input mains terminals. This allows the UPS to be configured for either a ‘split’ or ‘common’ bypass system – as explained below. Common-bypass configuration

In a ‘common-bypass’ installation the bypass supply lines are connected to the input mains terminals via the bypass links and there are no external power connections to the bypass terminals. Split-bypass configuration

In a ‘split-bypass’ installation the links between the input mains and bypass terminals are removed and a dedicated 3-phase bypass supply is connected to the bypass terminals. The advantage of this type of installation is that a separate power source may be used for the bypass lines which can be totally segregated from the UPS input mains, thus leaving the bypass supply available on occasions when the input mains supply has failed.

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1.4


“ 1+1” Parallel-modu le syst em Figure 1-5: “1+1” System configuration block diagram

RECTIFIER

INVERTER

Rectifier Control Logic

Inverter Control Logic

INV (SS)

Static Bypass

BYP (SS)

Static Switch Control Logic

Inter-Module Parallel Control Logic

Maint. Bypass

Maint. Bypass Static Switch Control Logic

Inter-Module Parallel Control Logic

Rectifier Control Logic

Inverter Control Logic

RECTIFIER

INVERTER

Output (LOAD) PowerSupply

Static Bypass

BYP (SS)

INV (SS)

As illustrated in Figure 1-5 above, the 7200 Series ‘1+1’ s ystem comprises two standard UPS modules, as used in a ‘single-module’ system, which are modified to allow their outputs to be connected in parallel. These can then be used in a ‘redundant’ or ‘non-redundant’ configuration as explained below. The diagram shows that from a ‘power’ viewpoint each module is internally identical to the ‘single-module’ configuration, with each module containing a rectifier, inverter, static switch (inverter and bypass ‘sides’), together with static bypass and maintenance bypass supplies. However, due to the parallel connection of the two modules’ outputs a “1+1” system requires additional inter-module control signals to manage current sharing, synchronising and bypass switching between the modules. As shown, the inter-module control features are implemented via a control bus connected between the two modules which affects the rectifier, inverter and static switch module control blocks. A brief description of the affects on each of these blocks is given below.

1.4.1

Redun dant vs Non-Redun dant conf igur ation Redundant system

If a ‘1+1’ system is configured as a ‘redundant’ system the modules are sized such that the potential maximum load can be powered by just one of the two modules. Under normal circumstances both modules are operational and share the load current equally; but if one module develops a fault, or is shut down, the second, healthy module is able to take over the full load demand and continue to provide it with processed, backed-up power.


1-7



Non-redundant system

In a ‘non-redundant’ configuration, the system is sized such that both UPS modules are required to feed the potential maximum load, and if either of the two modules develops a fault, or is for some reason shut down, the other module is automatically shut down also – note that in such an event the load is transferred to the static bypass supply, as described later. In terms of overall system reliability, the advantages of a redundant system over that of a non-redundant system are self evident. Changing a “1+1” system between a ‘redundant’ and ‘non-redundant’ configuration is quite straightforward, and is carried out by selecting configuration links on the control circuit boards fitted to both modules.

1.4.2

Inter-modul e pow er rectifi er cont rol The power rectifier is only affected by the parallel control bus in a “1+1” system if a ‘common battery’ is used – i.e. if both UPS modules are connected to a single battery bank (via separate battery isolators of course). In this type of installation the power rectifiers in each module are effectively connected in parallel and must be controlled such that the battery charge current is shared equally between them. A ‘common battery’ option kit is available. This contains DCCTs (DC Current Transformers) which are fitted to the battery power lines and connected via the parallel control bus to a sharing circuit in the rectifier control block. See the Options section in the relevant system IOM user manual for full details.

1.4.3

Inter-modul e inverter cont rol Synchronisation:

As the outputs from both UPS modules are connected together to provide a single critical load supply, it is imperative that the inverters are fully synchronised both in frequency and phase. This is achieved by digitally locking the two inverter control oscillators. Similarly, as has previously been mentioned, it is necessary for the inverters to be synchronised to the bypass supply to enable a ‘no-break’ transfer to take place when the static switch transfers the load to the bypass supply. The inverter control oscillators are therefore not only locked together but also made to track the bypass frequency. Current sharing:

The parallel control circuit compares each module's output current with that of its partner and is thereby able to effect current sharing by making fine adjustments to an individual module's output voltage. Reverse current:

A reverse current monitor circuit detects current flowing into, rather than out of, a module's output terminals. Such a condition can arise i f one module develops an internal power fault which sinks power from the second module’s output, or if for some reason the two modules become unbalanced. A reverse current is liable to further damage a module and also degrade the load supply. If a reverse current is detected the inverter on the affected module is immediately shut down and the load transferred to the bypass supply if the system is c onfigured to be non-redundant.

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1.4.4


Inter-modul e static swi tch cont rol Note: in the following text the term “inverter-side” static switch refers to the inverter output contactor.

There are three important conditions imposed on the static switch operation in a “1+1” system: 1. Under no circumstances must the inverter-side of one module be closed at the same time as the bypass-side is closed in the other module, as this would effectively parallel the output of one module with the bypass mains supply and likely to damage the system. 2. For similar reasons, the inverter-side of both modules must be opened if the maintenance bypass isolator is closed in either module. 3. Finally, when the system is started up the inverter-side must not be closed until its associated inverter is fully synchronised with the inverter in the second module. This is especially important in the case of a ‘redundant’ installation where one module may be on-line and supplying the load before the second module is started. In a ‘non-redundant’ configuration the start-up control sequence operates such that both inverters must be operating and fully synchronised before the static switch is allowed to transfer the load from the static bypass to the inverters. In a ‘non-redundant’ system the parallel control bus effectively ties together the static switches in both modules – i.e. both modules are either on inverter-side or bypass-side.


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Section 1:

Chapter 2 - Main Power Circuit Diagram Descriptions

2.1

Chapter overview This chapter contains individual descriptions of the Power Drawings for each of the 7200 Series models and should be read in conjunction with the appropriate circuit diagram and assembly drawings indicated in Table 1-2. Table 1-2: Model

Circuit Diagram

Assembly Diagram

30kVA

SE-5410303-P (3 pages)

AM-5410303-P (12 pages)

40kVA

SE-5410304-Q (3 pages)

AM-5410304-Q (12 pages)

60kVA

SE-5410308-U (3 pages)

AM-5410308-Q (12 pages)

Each drawing comprises several pages and a system of cross-referencing is used where connections are made across di fferent pages. The cross-reference takes the form of a page number followed by a grid reference and will be shown in the following text encased in square brackets – for example [2/C3] refers to page ‘2’ area ‘C3’. The grid reference system is shown on the left-side (A-R) and top (1-19) edges of the drawings.

30kVA Description – (see paragraph 2.2 on page 1-12) 40kVA Description – (see paragraph 2.3 on page 1-17) 60kVA Description – (see paragraph 2.4 on page 1-22)


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SECTION 1 - System Description CHAPTER 2 - Main Power Circuit Diagram Descri ptions

2.2


30kVA Model descr ipt ion – SE-5410303-P SE-5410303-P Page 1. This page shows the UPS input, rectifier, dc bus, inverter and output transformer power circuits. Bypass supply feed

The UPS input mains supply is connected to terminals U(1)-V(1)-W(1) which are in turn connected directly to the input switch Q1. If a ‘common bypass’ system is used the input supply terminals U(1)-V(1)-W(1) are connected by links to the bypass terminals U (3)-V(3)-W(3)-N(3) [2/G2]. If a ‘split-bypass’ system is used then these links must be removed and a dedicated bypass supply connected to U(3)-V(3)-W(3)-N(3) [page 2]. Input switch Q1 to rectifier

The input mains is connected to the rectifier via the input sw itch (Q1), input fuses F10-F12, RFI filter (Z1), optional input filter (4641015P) and input choke (L1). The input voltage is monitored by the control system via wi res 15-17 and the High Voltage Interface Board [3/N8]. This is used to detect input voltage failure (-20%), input phase rotation error and also provides basic phase-timing information for the rectifier SCR control logic. The V and W phases also power the control power supply transformer (T2) via F8 and F9. T2 primary has three taps which are selected according to the working voltage to produce a nominal 30Vac secondary voltage – tap selection details are shown on t he diagram [R6]. T2’s secondary feeds one input to the AC-DC Power Supply (4503030-M) [3/D19] Power rectifier block

The rectifier assembly, shown as a dashed block, is shown in detail in diagram SE-4612043-H (circuit diagram) and AM-4612043-H (assembly drawing). This assembly also contains the static switch power components in addition to those belonging to the rectifier. Considering the rectifier, this assembly contains the six SCRs associated with the rectifier together with their Gate Drive Control Board (SE-4542040-W) and snub ber board (SE-4540043-B). There are also two thermostats fitted to the U and V phase heatsinks (not normally used). The rectifier gate drive signals are applied to connector X7 on the Gate Driver Control Board (SE-4542040-W) via ribbon cable W4, and the rectifier’s output DC power rails are connected to the dc busbar via cables 27 (+) and 28 (-). DC Busbar

The DC busbar is controlled by the rectifier to be at the required battery charging voltage at all times and is smoothed by a capacitor bank (C1-C4) – less than 1% voltage ripple. The smoothed busbar is then connected to the batteries via an external circuit breaker, and to the inverter (4612143-D). In the battery line is a DCCT (T11) which provides the UPS control system with a battery current sense signal via the High Voltage Interface Board [3/G6] – used for battery current limit control and metering. A battery fuse (F13) is fitted and monitored by means of a micro-switch to detect its failure [3/G2]. Wires 27 and 28 provide the rectifier control system with a dc busbar (battery) feedback voltage via the High Voltage Interface Board [3/N9] – used for closedloop voltage control and dc bus (battery) voltage metering. The dc busbar is also connected to a DC-DC control power supply board [3/E7] via fuses F4-F5 – the

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SECTION 1 - System Description CHAPTER 2 - Main Power Circuit Diagram Descriptions

same fused supply is connected to the inverter output contactor control circuit on the static switch assembly [2/G8], described below. Power inverter

The inverter assembly, shown as a dashed block, is shown in detail in diagram SE-4612143-D (circuit diagram) and AM-4612143-D (assembly drawing). This assembly contains the six inverter IGBT transistors (3 x twin pack devices), three Base Drive Boards (4519015-H), and suppression capacitors. The transistor drive signals from the inverter control electronics are connected via ribbon cables W1-W2-W3 to CN1 on each Base Drive Board. Power inverter to output switch

The inverter output is connected to the output transformer where it is s tepped-up to the required output voltage. The output transformer step-up ratio is 1:2 and it is delta-star (zig-zag) wound with the output s tar point connected to the system’s neutral. Capacitors C5-C10, connected across the output line-to-line, act as a filter to remove any remnants of the PWM switching frequency from the output waveform, thus producing a clean sinusoidal output at the nominal output frequency. Current transformers T9 and T10 provide the inverter voltage regulation control system with output current sense signals, via the High Voltage Interface Board [3/G7-G8]. These are used by the inverter regulation control electronics to enhance the inverter regulation during load changes, and also by the output current limit protection control system. Wires 9-11 provide the inverter voltage control system with an output voltage feedback signal, via the High Voltage Interface Board [3/H4]. This is used by the inverter voltage regulation control system and static switch ‘fault and transfer’ control logic.

SE-5410303-P Page 2. This page shows the bypass input and UPS output power connections together with the bypass circuits. Bypass supply feed

If the UPS is connected with a ‘split-bypass’ supply the dedicated bypass supply is connected to U(3)-V(3)-W(3)-N(3) from where it is connected to the static bypass switch Q2 and maintenance bypass switch Q3. If a ‘common bypass’ system is used there are no external connections to U(3)-V(3)-W(3)-N(3) and the power to Q2 and Q3 is obtained from the UPS input mains supply terminals U(1)-V(1)-W(1) [page 1] via links which are connected between the mains and bypass input terminals [1/C2]. Maintenance bypass switch

The maintenance bypass switch (Q3) makes a direct connection between the bypass supply and UPS output terminals, therefore completely bypassing the UPS for maintenance and troubleshooting purposes. This switch is always open during normal UPS operation, and can be padlocked in that position. If the switch is closed while the inverter is operating (i.e. while Q4 is closed) its auxiliary contacts [3/L1] trigger a safety circuit in the UPS control system which will open the inverter output contactor to isolate the power inverter from the output terminals and prevent any damage which might otherwise occur due to reverse power flow.


1-13



Static bypass switch (Q2) to static switch assembly

Q2 connects the three-phase bypass supply to the static switch assembly and must be closed during normal UPS operation to ensure the availability of the static bypass supply when required. The bypass voltage at the switched side of Q2 is monitored by the High Voltage Interface Board via wires 1,2,3 and 4. This is used for bypass voltage error detection and inverter synchronisation control; the U and V phases also power the control power supply transformer (T3) via F6 and F7. T3 primary has three taps which are selected according to the working voltage to produce a nominal 30Vac secondary voltage – tap selection details are shown on the diagram [G6]. T3’s secondary feeds one input to the AC-DC Power Supply (4503030-M) [3/D19]. Static switch assembly

The static switch assembly, shown as a dashed block, is shown in detail in diagram SE-4612043-H (circuit diagram) and AM-4612043-H (assembly drawing). This assembly also contains the rectifier power components in addition to those belonging to the static switch, as described earlier. From the static switch point of view, this assembly contains the six SCRs associated with the bypass static switch together with their Gate Drive Control Board (SE-4542041-X) and snubber board (SE-4540043-B). All the connectors shown in the static bypass block on page 2 refer to the Gate Driver Control Board (SE-4542041-X): •

• • • •

Connector X13 is connected to the UPS Logic Board X5 [3/G16] and interfaces the Gate Driver Control Board with the remainder of the UPS control system via ribbon cable W7. Connector X10 monitors the inverter output contactor’s auxiliary contacts, which are used for interlocking and status indication purposes. Connector X9 carries the switched supply for energising the coil of the inverter output contactor. Connector X8 is connected to the DC busbar [1/H8] via F4-F5 and is the source of the inverter output contactor energising supply. Terminals A-C and A'-C' are the mains input/output power connections.

Static switch assembly to output switch Q4

The static switch power outputs are connected to the output switch (Q4) via an output RFI filter (Z2) and output current sensing CTs (T4-T6), which are used for metering purposes and overload monitoring. Note that the inverter output contactor is connected in parallel with the bypass static switch outputs and is fed from the output transformer [1/D18] Wires 5-8 are used for output voltage monitoring and metering purposes, and are connected to various sections of the UPS control system via the High Voltage Interface Board [3/N8]. They also provide power for the cooling fans which are all single-phase operating and distributed across the phases as shown. There is no fan redundancy, and the fan annotated ‘option input filter’ is fitted to the optional input filter cabinet. The output switch Q4 is a 4-pole switch with a set of auxiliary contacts which are monitored by the control system in the same manner as those described above for the maintenance bypass (Q3) [3/L1].

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Remote connections

The lower left-hand area of page 1 shows details of various remote connections to terminal block X3 (X3 connections are made by ‘spade connectors’). These connections are used for: •

Emergency stop – normally closed (volt-free) circuit connected between X3 terminals 10 and 11. If an external emergency stop option is not in use then these two terminals must be shorted together at the terminal block. • Battery temperature sensing – the battery temperature is sensed by the float charge control system such as to decrease the float voltage by 1.5Vdc/°C as the temperature increases above 25°C. The temperature sensor is connected between X3 terminals 2 and 3, and is polarity sensitive. Note: Only one temperature sensing device is used even if additional battery cabinets are utilised by the system. • Battery CB-AUX – the external battery circuit breaker auxiliary contacts are connected between X 3 terminals 4 (ground) and 3 such as to short these terminals together when the breaker is closed. • Battery trip – the battery circuit breaker is manually operated but can be tripped by the UPS control system if required – e.g. Low Battery trip when the battery discharges to 320Vdc. The trip circuit is connected via X3 terminals 4 (ground) and 6 (logic high to trip) and is normally applied to the breaker via an opto-coupled trip circuit for supply isolation.

SE-5410303-P Page 3. This page shows the UPS control system circuit boards and their interconnections. A basic description of the individual boards’ functions are provided below. High Voltage Interface Board 4590054-O

This board interfaces the high-voltage sense and control signals of the UPS power circuits with the low-voltage environment on the control circuit boards. • • • • • • • • • • • • • • • • • • • • • • •

X1 – connects the low voltage signals produced on this board to the UPS Logic Board from where they are transmitted to the remaining boards X2 – DC bus (battery) voltage sense inputs [1/G8] X3 – Input mains voltage sensing inputs [1/F7] X4 – UPS output voltage sensing inputs [2/H14] X5 – Inverter output voltage sensing inputs [1/C16] X6 – Bypass voltage sensing inputs [2/G5] X7 – Power switch auxiliary contacts X8 – Interface to external connection block X3 [2/M2-M5] X9 – Battery cabinet temperature sensor inputs [2/M3] X10 – Input air temperature sensor inputs for display metering X11 – Inverter output air temperature sensor inputs for display metering X12 – Transformer cabinet temperature sensor inputs for display metering X13 – Inverter assembly thermostats (n/c – open above 90°C) X14 – Not in use X15 – Battery fuse monitor [1/N4] X16 – Not in use (linked out) X17 – Not in use (linked out) X18 – Rectifier assembly thermostats (n/o – not normally used) X19 – Output current monitoring W-ph [2/F16] X20 – Output current monitoring V-ph [2/F16] X21 – Output current monitoring U-ph [2/F16] X22 – Battery current monitoring [1/M8] X23 – Not in use


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• • • •


X24 – Inverter current monitoring V-ph [1/E13] X25 – Inverter current monitoring W-ph [1/F14] X26 – Not in use X27 – Not in use

UPS Logic Board 4550004-E

This board serves two major functions: first it contains the logic which controls the static switch/inverter output contactor and load transfer between inverter and static bypass supplies. Second, it contains the fault-detection-based general system control logic which determines the operation of the rectifier (via the Rectifier Logic Board) and inverter (via the Inverter Logic Board). Note: When compared with the circuit boards fitted in the 7400 Series UPS, this board combines the UPS Logic Board and Static Switch Logic Board functions.

In addition to the above functions this board also provides an interface between the general control system and the Operator Panel and external alarms option. Rectifier Logic Board 4520074-A

The Rectifier Logic Board provides the rectifier SCRs with their gate drive signals at a suitable conduction angle to produce the required battery charge voltage. It receives battery voltage and battery current feedback signals, and input voltage sense signals via the High Voltage Interface Board and UPS Logic Board. The drive pulses are processed on the Rectifier Gate Drive Board (4542040-W) before application to the SCR gates. The Rectifier Logic Board receives its operating power from the AC-DC Power Supply assembly (4503030-M) which is energised whenever the input mains supply or bypass supply is live (via T2 [1/K5]) or (via T3 [2/H7]) – i.e. both these transformers feed the same power supply circuit in parallel. Inverter Logic Board 4530024-S

The Inverter Logic Board provides the inverter IGBTs with their base drive signals with a suitable PWM pattern to produce the required output voltage. It receives output voltage and current feedback signals, and bypass voltage sense signals via the High Voltage Interface Board and UPS Logic Board. The drive pulses are processed on the Inverter Drive Interface Boards (4519015-H) before application to the IGBTs. The Inverter Logic Board receives its operating power from the DC-DC Power Supply assembly (4503028-K) which is energised via fuses F4-F5 [1/H8] whenever the DC busbar is live – i.e. either due to the rectifier being operative (when the input mains is present) or when the batteries are connected to the dc busbar (external circuit breaker closed). Control power supplies

The power supplies from the Inverter Logic Board and Rectifier Logic Board are paralleled on the UPS Logic Board and fed to the other boards as necessary. Therefore when the UPS is started-up the ‘control system’ is powered-up as soon as the AC-DC Power Supply is energised by the closure of the input mains sw itch (Q1). Once the rectifier is fully operational the DC-DC P ower Supply provides an alternative (parallel) supply source which supports the control system operation if the input mains supply subsequently fails. Note: the Inverter Logic Board and Inverter Driver Board are energised from the DC-DC supply only.

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2.3


40kVA Model descr ipt ion – SE-5410304-Q SE-5410304-Q Page 1. This page shows the bypass input and UPS output power connections together with the bypass circuits. Bypass supply feed

If the UPS is connected with a ‘split-bypass’ supply the dedicated bypass supply is connected to U(3)-V(3)-W(3)-N(3) from where it is connected to the static bypass switch Q2 and maintenance bypass switch Q3. If a ‘common bypass’ system is used, there are no external connections to U(3)-V(3)-W(3)-N(3) and the power for Q2 and Q3 is obtained from the UPS input mains supply terminals U(1)-V(1)-W(1) [page 2] via links which are connected between the mains and bypass input terminals [2/C2]. Maintenance bypass switch

The maintenance bypass switch (Q3) makes a direct connection between the bypass supply and UPS output terminals, therefore completely bypassing the UPS for maintenance and troubleshooting purposes. This switch is always open during normal UPS operation, and can be padlocked in the open position. If the switch is closed while the inverter is operating (i.e. while Q4 is closed) its auxiliary contacts [3/L1] will trigger a safety circuit in the UPS control system which will open the inverter output contactor to isolate the power inverter from the output terminals and prevent any damage which might otherwise occur due to a reverse power flow. Static bypass switch (Q2) to static switch assembly

Q2 connects the three-phase bypass supply to the static switch assembly and must be closed during normal UPS operation to ensure the availability of the static bypass supply when required. The bypass voltage at the switched side of Q2 is monitored by the High Voltage Interface Board via wires 1,2,3 and 4. This is used for bypass voltage error detection and inverter synchronisation control; the U and V phases also power the control power supply transformer (T3) via F6 and F7. T3 primary has three taps which are selected according to the working voltage to produce a nominal 30Vac secondary voltage – tap selection details are shown on the diagram. T3’s secondary feeds one input to the AC-DC Power Supply (4503030-M) [3/D19]. Static switch assembly

The static switch assembly, shown as a dashed block, is shown in detail in diagram SE-4612044-I (circuit diagram) and AM-4612044-I (assembly drawing). This assembly also contains the rectifier power components in addition to those belonging to the static switch. From the static switch point of view, this assembly contains the six SCRs ass ociated with the bypass static switch together with their Gate Drive Control Board (SE-4542041-X) and snubber board (SE-4540043-B). All the connectors shown in the static bypass block on page 1 refer to the Gate Driver Control Board (SE-4542041-X): •

•

Connector X13 is connected to the UPS Logic Board X5 [3/G16] and interfaces the Gate Driver Control Board with the remainder of the UPS control system via ribbon cable W7. Connector X10 monitors the inverter output contactor’s auxiliary contacts,


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• •

•


which are used for interlocking and status indication purposes. Connector X9 carries the switched supply for energising the coil of the inverter output contactor. Connector X8 is connected to the DC busbar [2/H8] via F4-F5 and is the source of the inverter output contactor energising supply mentioned above. Terminals A-C and A'-C' are the mains input/output power connections.


The static switch power outputs are connected to the output switch (Q4) via an output RFI filter (Z2) and output current sensing CTs (T4-T6), which are used for metering and overload monitoring purposes. Note that the inverter output contactor is connected in parallel with the bypass static switch outputs and is fed from the output transformer [2/B17-B18] Wires 5-8 are used for output voltage monitoring and metering purposes, and are connected to various sections of the UPS control system via the High Voltage Interface Board [3/N8]. They also provide power for the cooling fans which are all single-phase operating and distributed across the phases as shown. There is no fan redundancy, and the fan annotated ‘option input filter’ is fitted to the optional input filter cabinet. The output switch Q4 is a 4-pole switch with a set of auxiliary contacts which are monitored by the control system in the same manner as those described above for the maintenance bypass switch (Q3). Remote connections

The lower left-hand ares of page 1 shows details of various remote connections to terminal block X3 (X3 connections are made by ‘spade connectors’). These connections are used for: •

Emergency stop – normally closed (volt-free) circuit connected between X3 terminals 10 and 11. If an external emergency stop option is not in use then these two terminals must be shorted together at the terminal block. • Battery temperature sensing – the battery temperature is sensed by the float charge control system such as to decrease the float voltage by 1.5Vdc/°C as the temperature increases between 25°C and 35°C. The tem perature sensor is connected between X3 terminals 2 and 3, and is polarity sensitive. • Battery CB-AUX – the external battery circuit breaker auxiliary contacts are connected between X 3 terminals 4 (ground) and 3 such as to short these terminals together when the breaker is closed. • Battery trip – the battery circuit breaker is manually operated but can be tripped by the UPS control system if required – e.g. Low Battery trip when the battery discharges to 320Vdc. The trip circuit is connected via X3 terminals 4 (ground) and 6 (logic high to trip) and is normally applied to the breaker via an opto-coupled trip circuit for supply isolation.

SE-5410304-Q Page 2. This page shows the UPS input, rectifier, dc bus, inverter and output transformer power circuits. Bypass supply feed

The UPS input mains supply is connected to terminals U(1)-V(1)-W(1) which are in turn connected directly to the input switch Q1.

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If a ‘common bypass’ system is used the input supply terminals U(1)-V(1)-W(1) are connected by links to the bypass terminals U(3)-V(3)-W(3)-N(3) [1/C1]. If a ‘split-bypass’ system is used then these links must be removed and a dedicated bypass supply is connected to U(3)-V(3)-W(3)-N(3) [page 1]. Input switch Q1 to rectifier

The input mains passes from the input switch Q1 to the rectifier via the input fuses F10-F12, input RFI filter (Z1), optional input filter (4641016-Q) and input filter choke. The input voltage is monitored by the control system via wi res 15-17 and the High Voltage Interface Board [3/N8]. This is used to detect input voltage failure (-20%), input phase rotation error and also provides basic phase-timing information for the rectifier SCR control logic. The V and W phases also power the control power supply transformer (T2) via F8 and F9. This transformer is identical to T3 which is fed from the bypass supply and described on the previous page, and once again its primary is tapped to suit the working mains supply voltage – tap details shown on [2/P7]. Power rectifier block

The rectifier assembly, shown as a dashed block, is shown in detail in diagram SE-4612044-I (circuit diagram) and AM-4612044-I (assembly drawing). This assembly also contains the static switch power components in addition to those belonging to the rectifier. Considering the rectifier, this assembly contains the six SCRs associated with the rectifier together with their Gate Drive Control Board (SE-4542040-W) and snub ber board (SE-4540043-B). There are also two thermostats fitted to the U and V phase heatsinks but these are not normally used. The rectifier gate drive signals are applied to connector X7 on the Gate Driver Control Board (SE-4542040-W) via ribbon cable W4, and the rectifier’s output DC power rails are connected to the dc busbar via cables 27 (+) and 28 (-). DC Busbar

The DC busbar is controlled by the rectifier to be at the required battery charging voltage at all times and is smoothed by a capacitor bank (C1-C4) – less than 1% voltage ripple. The smoothed busbar is then connected to the batteries via an external circuit breaker, and to the inverter (4612145-F). In the battery line is a DCCT (T11) which provides the UPS control system with a battery current sense signal via the High Voltage Interface Board [3/G6], and a battery fuse (F13) which is monitored by means of a micro-switch to detect its failure. Wires 27 and 28 provide the rectifier control system with a dc busbar (battery) feedback voltage via the High Voltage Interface Board [3/N9] – used for closedloop voltage control and dc bus (battery) voltage metering. This signal also provides a battery voltage metering function. The dc busbar is also connected to a DC-DC control power supply board [3/E7] via fuses F4-F5 (1A) – the same fused supply is connected to the inverter output contactor control circuit on the static switch assembly [1/G8], as described earlier. Power inverter

The inverter assembly, shown as a dashed block, is shown in detail in diagram SE-4612145-F (circuit diagram) and AM-4612145-F (assembly drawing). This assembly contains the six inverter IGBT transistors (single pack devices), three


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Base Drive Boards (4519015-H), suppression capacitors and two normally-closed series-connected thermostats. The transistor drive signals from the inverter control electronics are connected via ribbon cables W1-W2-W3 to CN1 on each Base Drive Board. Power inverter to output switch

The inverter output is connected to the output transformer where it is s tepped-up to the required output voltage. The output transformer step-up ratio is 1:2 and it is delta-star (zig-zag) wound with the output s tar point connected to the system’s neutral. Capacitors C5-C10 connected across the output line-to-line act as a filter to remove any remnants of the PWM switching frequency from the output waveform, thus producing a clean sinusoidal output at the nominal output frequency. Current transformers T9 and T10 provide the inverter voltage regulation control system with output current sense signals, via the High Voltage Interface Board [3/G7-G8]. These are used by the inverter regulation control electronics to enhance the inverter regulation during load changes, and also by the output current limit protection control system. Wires 9-11 provide the inverter voltage control system with an output voltage feedback signal, via the High Voltage Interface Board [3/H4]. This is used by the inverter voltage regulation control circuits and static switch ‘fault and transfer’ control logic.

SE-5410304-Q Page 3. This page shows the UPS control system circuit boards and their interconnections. A basic description of the individual boards’ functions are provided below. High Voltage Interface Board 4590054-O

This board interfaces the high-voltage sense and control signals of the UPS power circuits with the low-voltage environment on the control circuit boards. • • • • • • • • • • • • • • • • • • • •

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X1 – connects the low voltage signals produced on this board to the UPS Logic Board from where they are transmitted to the remaining boards X2 – DC bus (battery) voltage sense inputs [2/G8]. X3 – Input mains voltage sensing inputs [2/F7] X4 – UPS output voltage sensing inputs [1/H14] X5 – Inverter output voltage sensing inputs [2/C16] X6 – Bypass voltage sensing inputs [1/G5] X7 – Power switch auxiliary contacts X8 – Interface to external connection block X3 [1/M3] X9 – Battery cabinet temperature sensor inputs [1/M3] X10 – Input air temperature sensor inputs for display metering X11 – Inverter output air temperature sensor inputs for display metering X12 – Transformer cabinet temperature sensor inputs for display metering X13 – Inverter assembly thermostats (n/c – open above 90°C) X14 – Not in use X15 – Battery fuse monitor [1/N4] X16 – Not in use (linked out) X17 – Not in use (linked out) X18 – Rectifier assembly thermostats (n/o – not normally used) X19 – Output current monitoring W-ph [1/F16] X20 – Output current monitoring V-ph [1/F16]



• • • • • • •


X21 – Output current monitoring U-ph [1/F16] X22 – Battery current monitoring [2/M8] X23 – Not in use X24 – Inverter current monitoring V-ph [2/E13] X25 – Inverter current monitoring W-ph [2/F14] X26 – Not in use X27 – Not in use


This board serves two major functions: •

first it contains the logic which controls the static switch/inverter output contactor and load transfer between inverter and static bypass supplies. • second, it contains the fault-detection-based general system control logic which determines the operation of the rectifier (via the Rectifier Logic Board) and inverter (via the inverter Logic Board). Note: When compared with the circuit boards fitted in the 7400 Series UPS, this board combines the UPS Logic Board and Static Switch Logic Board functions. In addition to the above functions this board also provides an interface between the general control system and the Operator Panel and external alarms option. Rectifier Logic Board 4520074-A


The Inverter Logic Board provides the inverter IGBTs with their base drive signals with a suitable PWM pattern to produce the required output voltage. It receives output voltage and current feedback signals, and bypass voltage sense signals via the High Voltage Interface Board and UPS Logic Board. The drive pulses are processed on the Inverter Drive Interface Boards (4519015-H) before application to the IGBTs. The Inverter Logic Board receives its operating power from the DC-DC Power Supply assembly (4503028-K) which is energised via fuses F4-F5 [2/H8] whenever the DC busbar is live – i.e. either due to the rectifier being operative (when the input mains is present) or when the batteries are connected to the dc busbar (external circuit breaker closed). Control power supplies

The power supplies from the Inverter Logic Board and Rectifier Logic Board are paralleled on the UPS Logic Board and fed to the other boards in the control system as necessary. Therefore when the UPS is started-up the ‘control system’ is powered-up as soon as the AC-DC Power Supply is energised by the closure of the input mains switch (Q1). Once the rectifier is fully operational the DC-DC


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Power Supply provides an alternative (parallel) supply source which supports the control system operation if the input mains supply subsequently fails. The power supplies from the Inverter Logic Board and Rectifier Logic Board are paralleled on the UPS Logic Board and fed to the other boards as necessary. Therefore when the UPS is started-up the ‘control system’ is powered-up as soon as the AC-DC Power Supply is energised by the closure of the input mains sw itch (Q1). Once the rectifier is fully operational the DC-DC P ower Supply provides an alternative (parallel) supply source which supports the control system operation if the input mains supply subsequently fails. Note: the Inverter Logic Board and Inverter Driver Board are energised from the DC-DC supply only.

2.4

60kVA Model descr ipt ion – SE-5410308-U SE-5410308-U Page 1. This page shows the bypass input and UPS output power connections together with the bypass circuits. Bypass supply feed

If the UPS is connected with a ‘split-bypass’ supply the dedicated bypass supply is connected to U(3)-V(3)-W(3)-N(3) from where it is connected to the static bypass switch Q2 and maintenance bypass switch Q3. If a ‘common bypass’ system is used, there are no external connections to U(3)-V(3)-W(3)-N(3) and the power for Q2 and Q3 is obtained from the UPS input mains supply terminals U(1)-V(1)-W(1) [page 2] via links which are connected between the mains and bypass input terminals [2/C2]. Maintenance bypass switch

The maintenance bypass switch (Q3) makes a direct connection between the bypass supply and UPS output terminals, therefore completely bypassing the UPS for maintenance and troubleshooting purposes. This switch is always open during normal UPS operation, and can be padlocked in the open position. If the switch is closed while the inverter is operating (i.e. while Q4 is closed) its auxiliary contacts [3/L1] will trigger a safety circuit in the UPS control system which will open the inverter output contactor to isolate the power inverter from the output terminals and prevent any damage which might otherwise occur due to a reverse power flow. Static bypass switch (Q2) to static switch assembly

Q2 connects the three-phase bypass supply to the static switch assembly and must be closed during normal UPS operation to ensure the availability of the static bypass supply when required. The bypass voltage at the switched side of Q2 is monitored by the High Voltage Interface Board via wires 1,2,3 and 4. This is used for bypass voltage error detection and inverter synchronisation control; the U and V phases also power the control power supply transformer (T3) via F6 and F7. T3 primary has three taps which are selected according to the working voltage to produce a nominal 30Vac secondary voltage – tap selection details are shown on the diagram. T3’s secondary feeds one input to the AC-DC Power Supply (4503030-M) [3/D19].

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Static switch assembly

The static switch assembly, shown as a dashed block, is shown in detail in diagram SE-4612045-J (circuit diagram) and AM-4612045-J (assembly drawing). This assembly also contains the rectifier power components in addition to those belonging to the static switch. From the static switch point of view, this assembly contains the six SCRs ass ociated with the bypass static switch together with their Gate Drive Control Board (SE-4542041-X) and snubber board (SE-4540043-B). All the connectors shown in the static bypass block on page 1 refer to the Gate Driver Control Board (SE-4542041-X): •

• • •

•

Connector X13 is connected to the UPS Logic Board X5 [3/G16] and interfaces the Gate Driver Control Board with the remainder of the UPS control system via ribbon cable W7. Connector X10 monitors the inverter output contactor’s auxiliary contacts, which are used for interlocking and status indication purposes. Connector X9 carries the switched supply for energising the coil of the inverter output contactor. Connector X8 is connected to the DC busbar [2/H8] via F4-F5 and is the source of the inverter output contactor energising supply mentioned above. Terminals A-C and A'-C' are the mains input/output power connections.


The static switch power outputs are connected to the output switch (Q4) via an output RFI filter (Z2) and output current sensing CTs (T4-T6), which are used for metering and overload monitoring purposes [3/G6]. Note that the inverter output contactor is connected in parallel with the bypass static switch outputs and is fed from the output transformer [2/B17-B18] Wires 5-8 are used for output voltage monitoring and metering purposes, and are connected to various sections of the UPS control system via the High Voltage Interface Board [3/N8]. They also provide power for the cooling fans which are all single-phase operating and distributed across the phases as shown. The output switch Q4 is a 4-pole switch with a set of auxiliary contacts which are monitored by the control system in the same manner as those described above for the maintenance bypass switch (Q3). Remote connections

The lower left-hand ares of page 1 shows details of various remote connections to terminal block X3 (X3 connections are made by ‘spade connectors’). These connections are used for: •

Emergency stop – normally closed (volt-free) circuit connected between X3 terminals 10 and 11. If an external emergency stop option is not in use then these two terminals must be shorted together at the terminal block. • Battery temperature sensing – the battery temperature is sensed by the float charge control system such as to decrease the float voltage by 1.5Vdc/°C as the temperature increases between 25°C and 35°C. The tem perature sensor is connected between X3 terminals 2 and 3, and is polarity sensitive. • Battery CB-AUX – the external battery circuit breaker auxiliary contacts are connected between X 3 terminals 4 (ground) and 3 such as to short


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these terminals together when the breaker is closed. • Battery trip – the battery circuit breaker is manually operated but can be tripped by the UPS control system if required – e.g. Low Battery trip when the battery discharges to 320Vdc. The trip circuit is connected via X3 terminals 4 (ground) and 6 (logic high to trip) and is normally applied to the breaker via an opto-coupled trip circuit for supply isolation.

SE-5410308-U Page 2. This page shows the UPS input, rectifier, dc bus, inverter and output transformer power circuits. Bypass supply feed

The UPS input mains supply is connected to terminals U(1)-V(1)-W(1) which are in turn connected directly to the input switch Q1. If a ‘common bypass’ system is used the input supply terminals U(1)-V(1)-W(1) are connected by links to the bypass terminals U(3)-V(3)-W(3)-N(3) [1/C1]. If a ‘split-bypass’ system is used then these links must be removed and a dedicated bypass supply is connected to U(3)-V(3)-W(3)-N(3) [page 1]. Input switch Q1 to rectifier

The input mains passes from the input switch Q1 to the rectifier via the input fuses F10-F12, input RFI filter (Z1), optional input filter (4641017-R) and input filter choke. The input voltage is monitored by the control system via wi res 15-17 and the High Voltage Interface Board [3/N8]. This is used to detect input voltage failure (-20%), input phase rotation error and also provides basic phase-timing information for the rectifier SCR control logic. The V and W phases also power the control power supply transformer (T2) via F8 and F9 (1A). This transformer is identical to T3 which is fed from the bypass supply and described on the previous page, and once again its primary is tapped to suit the working mains supply voltage – tap details shown on [2/P7]. Power rectifier block

The rectifier assembly, shown as a dashed block, is shown in detail in diagram SE-4612047-R (circuit diagram) and AM-4612047-R (assembly drawing). This assembly also contains the static switch power components in addition to those belonging to the rectifier. Considering the rectifier, this assembly contains the six SCRs associated with the rectifier together with their Gate Drive Control Board (SE-4542040-W) and snub ber board (SE-4540043-B). There are also two thermostats fitted to the U and V phase heatsinks (not normally used). The rectifier gate drive signals are applied to connector X7 on the Gate Driver Control Board (SE-4542040-W) via ribbon cable W4, and the rectifier’s output DC power rails are connected to the dc busbar via cables 27 (+) and 28 (-). DC Busbar

The DC busbar is controlled by the rectifier to be at the required battery charging voltage at all times and is smoothed by a capacitor bank (C1-C4) – less than 1% voltage ripple. The smoothed busbar is then connected to the batteries via an external circuit breaker, and to the inverter (4612145-F). In the battery line is a DCCT (T11) which provides the UPS control system with a battery current sense signal via the High Voltage Interface Board [3/G6], and a battery fuse (F13) which is monitored by means of a micro-switch to detect its failure.

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Wires 27 and 28 provide the rectifier control system with a dc busbar (battery) feedback voltage via the High Voltage Interface Board [3/N9] – used for closedloop voltage control and dc bus (battery) voltage metering. This signal also provides a battery voltage metering function. The dc busbar is also connected to a DC-DC control power supply board [3/E7] via fuses F4-F5 (1A) – the same fused supply is connected to the inverter output contactor control circuit on the static switch assembly [1/G8], as described earlier. Power inverter

The inverter assembly, shown as a dashed block, is shown in detail in diagram SE-4612145-F (circuit diagram) and AM-4612145-F (assembly drawing). This assembly contains the six inverter IGBT transistors (single pack devices), three Base Drive Boards (4519015-H), suppression capacitors and two normally-closed series-connected thermostats. The transistor drive signals are connected via ribbon cables W1-W2-W3 to CN1 on each Base Drive Board. Power inverter to output switch

The inverter output is connected to the output transformer where it is s tepped-up to the required output voltage. The output transformer step-up ratio is 1:2 and it is delta-star (zig-zag) wound with the output s tar point connected to the system’s neutral. Capacitors C5-C10 connected across the output line-to-line act as a filter to remove any remnants of the PWM switching frequency from the output waveform, thus producing a clean sinusoidal output at the nominal output frequency. Current transformers T9 and T10 provide the inverter voltage regulation control system with output current sense signals, via the High Voltage Interface Board [3/G7-G8]. These are used by the inverter regulation control electronics to enhance the inverter regulation during load changes, and also by the output current limit protection control system. Wires 9-11 provide the inverter voltage control system with an output voltage feedback signal, via the High Voltage Interface Board [3/H4]. This is used by the inverter voltage regulation control circuits and static switch ‘fault and transfer’ control logic

SE-5410308-U Page 3. This page shows the UPS control system circuit boards and their interconnections. A basic description of the individual boards’ functions are provided below. High Voltage Interface Board 4590054-O

This board interfaces the high-voltage sense and control signals of the UPS power circuits with the low-voltage environment on the control circuit boards. •

• • • • • •

X1 – connects the low voltage signals produced on this board to the UPS Logic Board from where they are transmitted to the remaining boards as required. X2 – DC bus (battery) voltage sense inputs [2/G8]. X3 – Input mains voltage sensing inputs [2/F7] X4 – UPS output voltage sensing inputs [1/H14] X5 – Inverter output voltage sensing inputs [2/C16] X6 – Bypass voltage sensing inputs [1/G5] X7 – Power switch auxiliary contacts


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• • • • • • • • • • • • • • • • • • • •


X8 – Interface to external connection block X3 [1/M3] X9 – Battery cabinet temperature sensor inputs [1/M3] X10 – Input air temperature sensor inputs for display metering X11 – Inverter output air temperature sensor inputs for display metering X12 – Transformer cabinet temperature sensor inputs for display metering X13 – Inverter assembly thermostats (n/c – open above 90°C) X14 – Not in use X15 – Battery fuse monitor [1/N4] X16 – Not in use (linked out) X17 – Not in use (linked out) X18 – Rectifier assembly thermostats (n/o – not normally used) X19 – Output current monitoring W-ph [1/F16] X20 – Output current monitoring V-ph [1/F16] X21 – Output current monitoring U-ph [1/F16] X22 – Battery current monitoring [2/M8] X23 – Not in use X24 – Inverter current monitoring V-ph [2/E13] X25 – Inverter current monitoring W-ph [2/F14] X26 – Not in use X27 – Not in use


This board serves two major functions: •

first it contains the logic which controls the static switch/inverter output contactor and load transfer between inverter and static bypass supplies. • second, it contains the fault-detection-based general system control logic which determines the operation of the rectifier (via the Rectifier Logic Board) and inverter (via the inverter Logic Board). Note: When compared with the circuit boards fitted in the 7400 Series UPS, this board combines the UPS Logic Board and Static Switch Logic Board functions. In addition to the above functions this board also provides an interface between the general control system and the Operator Panel and external alarms option. Rectifier Logic Board 4520074-A


The Inverter Logic Board provides the inverter IGBTs with their base drive signals with a suitable PWM pattern to produce the required output voltage. It receives output voltage and current feedback signals, and bypass voltage sense signals via the High Voltage Interface Board and UPS Logic Board. The drive pulses are processed on the Inverter Drive Interface Boards (4519015-H) before application to the IGBTs.

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The Inverter Logic Board receives its operating power from the DC-DC Power Supply assembly (4503028-K) which is energised via fuses F4-F5 [2/H8] whenever the DC busbar is live – i.e. either due to the rectifier being operative (when the input mains is present) or when the batteries are connected to the dc busbar (external circuit breaker closed). Control power supplies

The power supplies from the Inverter Logic Board and Rectifier Logic Board are paralleled on the UPS Logic Board and fed to the other boards in the control system as necessary. Therefore when the UPS is started-up the ‘control system’ is powered-up as soon as the AC-DC Power Supply is energised by the closure of the input mains switch (Q1). Once the rectifier is fully operational the DC-DC Power Supply provides an alternative (parallel) supply source which supports the control system operation if the input mains supply subsequently fails. Note: the Inverter Logic Board and Inverter Driver Board are energised from the DC-DC supply only.


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Sect-1

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