GIS 12 206 5 February 2003

Document No.

GIS 12-206

Applicability

Group

Date

5 February 2003

Guidance on Industry Standard for Synchronous Motors (API 546)

GIS 12-206

BP GROUP

ENGINEERING TECHNICAL PRACTICES

5 February 2003

GIS 12-206 Guidance on Industry Standard for Synchronous Motors (API 546)

Foreword This is the first issue of Engineering Technical Practice (ETP) GIS 12-206. This Guidance on Industry Standard (GIS) is based on parts of heritage documents from the merged BP companies as follows:

Amoco A EL-MT-546-P

Electrical—Motors—Synchronous—Supply Specification

Arco ES 403-91

Form-Wound Brushless Synchronous Motors 500 Horsepower and Larger

Downloaded Date: 6/17/2008 10:15:19 PM The latest update of this document is located in the BP ETP and Projects Library

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Table of Contents Page Foreword ........................................................................................................................................ 2 Scope ............................................................................................................................................. 4 Section 1 – General ........................................................................................................................ 4 1.1 Scope ......................................................................................................................... 4 1.6 Referenced publications.............................................................................................. 4 Section 2 - Basic design.................................................................................................................. 4 2.1 General....................................................................................................................... 4 2.2 Electrical design.......................................................................................................... 4 2.3 Insulation systems ...................................................................................................... 5 2.4 Mechanical design ...................................................................................................... 5 Section 3 - Accessories................................................................................................................. 10 3.1 Terminal boxes ......................................................................................................... 10 3.2 Winding temperature detectors ................................................................................. 10 3.3 Bearing temperature detectors.................................................................................. 11 3.4 Space heaters........................................................................................................... 11 3.5 Screens and filters .................................................................................................... 11 3.6 Alarms and control devices for motor protection ....................................................... 11 3.8 Vibration detectors .................................................................................................... 12 Section 4 – Inspection, testing, and preparation for shipment ....................................................... 12 4.3 Final testing .............................................................................................................. 12 4.4 Preparation for shipment........................................................................................... 12 Section 6 - Vendor’s data.............................................................................................................. 13 6.1 Proposals.................................................................................................................. 13


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Scope This GIS provides guidance on industry standard for the design, materials, fabrication, inspection, testing, documentation, and preparation for shipment of synchronous motors based on API Standard 546, Brushless Synchronous Machines—500 kVa and Larger, Second Edition, June 1997. Numbering of the following sections and paragraphs corresponds to section and paragraph numbering of API 546 and reflects additions, deletions, and revisions. Requirements of API 546 that are not revised remain applicable.

Section 1 – General 1.1

Scope

1.1.2

Revise to read: Motors are special purpose. Paragraphs that begin with square bullets shall apply.

1.6

Referenced publications Add to ASME: B17.1

Keys and Keyseats

B106.1M

Design of Transmission Shafting

Add to IEEE: 1043 Recommended Practice for Voltage Endurance Testing of Form-Wound Bars and Coils Add to NEMA: MG 3

Sound Level Prediction for Installed Rotating Electrical Machines

Section 2 - Basic design 2.1

General

2.1.3

Revise to read: Maximum permissible sound pressure level for closed machines shall not exceed 85 dBA at a distance of 3 feet from motor enclosure. a.

Measuring and reporting of sound-level data shall be per IEEE 85.

b.

Sound pressure level shall be determined per NEMA MG 3.

2.2

Electrical design

2.2.2

Stator windings

Add: 2.2.2.3

End winding bracing rings shall be provided as follows: End Head Overhang Length (From core) Standard Duty

2.2.2.4

Severe Duty

No rings One ring

< 8 in

< 8 in

≥ 8 in < 15 in

≥ 8 in < 12 in

Two rings

≥ 15 in

≥ 12 in

Duty level shall be obtained from Company. Downloaded Date: 6/17/2008 10:15:19 PM The latest update of this document is located in the BP ETP and Projects Library

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2.2.2.5


For coils and bars: a.

End-head drop back shall be consistent in all planes, one coil bar to another.

b.

Spaces between end arms shall be consistent on completed winding.

2.2.6

Starting capabilities

2.2.6.1

Add: Starting capabilities shall be per NEMA MG-1, 21.13.1

2.3

Insulation systems

2.3.1

General requirements

2.3.1.1

Add:

2.3.1.3

a.

Mica paper ground wall insulation with non-mylar or non-Polyethelyneterephtalate (PET) backing shall be provided. Mylar and PET shall not be used

b.

A minimum of 2 (1/2) layers of mica paper ground wall insulation with non-mylar or PET backing shall be provided for dedicated turn insulation.

c.

Above 6 kV, stator-winding stress gradient tape shall be provided.

d.

Semi-conducting paint shall not be used on stator winding end turns.

e.

Stator winding insulation ground-wall voltage stress shall not exceed 72 volts/mil.

f.

Stator winding strands shall be insulated and shall be constructed to minimize both void count and size.

g.

Insulation on stator winding end turns, leads, and interconnecting wiring shall be at least as thick as insulation on windings.

Add after last sentence of first paragraph: Rotor insulation system shall be protected from transient overvoltages. A spark gap shall not be used.

2.3.1.3

Revise last sentence to read: Conductors from pole-piece to pole-piece in main rotor field shall be independently secured at exit and entry points on pole winding.

2.3.1.4

Add: Insulation on rotor winding end turns, leads, and interconnecting wiring shall be at least as thick as insulation on the main winding.

2.4

Mechanical design

2.4.1

Enclosures

2.4.1.2

Motor enclosures and corresponding NEMA or IEC specifications

2.4.1.2.3.b Delete “aluminum plate” from first sentence. Add: 2.4.1.3

Exciter enclosure

a.

Exciter shall either be built into or ventilated from motor enclosure.

b.

Exciter enclosure shall be same NEMA class as motor.

c.

Excitation system shall be readily accessible (as defined by NEC, Article 100 A). Downloaded Date: 6/17/2008 10:15:19 PM The latest update of this document is located in the BP ETP and Projects Library

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2.4.2

Frame and mounting plates

2.4.2.1

Revise second sentence to read (formula remains the same): The frame of the completely assembled machine on its permanent foundation, with the rotor installed and rotating on its oil film, shall be free from structural resonance within ±10% of both the electric line frequency and twice the line frequency, and the following frequency ranges: This requires more than the standard +/–5%.

2.4.2.15

Revise to read: All fabricated welded structural steel shall be post-weld stress relieved unless stress relieving is not practical due to motor design. In cases where post-weld stress relief is not practical, vendor shall provide documentation upon request detailing weld procedures and past history.

2.4.5

Rotating element

2.4.5.1

General

2.4.5.1.2

Add: No shaft repairs shall be made by plating, metal spray, or welding.

Add: 2.4.5.1.6

Shafts shall comply with the following: a.

Keyways shall have radii as specified in ASME B17.1.

b.

Shaft shall have minimum Factor of Safety, as defined by ASME B106.1M, of 2.0.

c.

Cyclic-torsional loads shall be calculated per Mechanical Engineering Design, 1989, 18-7.

2.4.5.2

Assembly

2.4.5.2.2

Revise to read: Fabricated-bar amortisseur winding shall be furnished with copper or phosphorous-free copperalloy bars and end rings.

2.4.5.2.10 Revise first sentence to read: Fans shall not be mounted on the amortisseur winding end ring. Natural frequencies of fan or individual fan blades shall be removed from following values by 10% or more: a.

One and two times electrical line frequency.

b.

One times, 2 times, and 3 times running speed.

2.4.6

Dynamics

2.4.6.1

Resonances

2.4.6.1.2.b Add: Vendor shall provide complete bearing geometry, including all manufacturing tolerances, as well as fit of bearing within bearing housing. 2.4.6.1.2.c Add: Vendor shall state the basis for these stiffnesses, whether measured or calculated, including any assumptions.


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2.4.6.2

Dynamic analysis

2.4.6.2.2

Revise paragraph to read: Vendor shall provide a damped unbalance response for motors 1500 hp and greater to ensure acceptable amplitudes and separation margins at any speed from zero to trip. This analysis shall be submitted to purchaser within two months of receipt of order. A typical undamped critical speed map, including bearing support stiffness curves, shall be provided with the vendor’s proposal for all motors, regardless of size, for a motor with same frame size, rotor geometry, and bearings to be utilized for the proposed motor.

2.4.6.2.2.1.c

Add:

Vendor shall provide the complete bearing geometry, including all manufacturing tolerances, as well as the fit of the bearing within the bearing housing, with the rotor dynamics report. 2.4.6.2.2.1.e

Add:

Vendor shall provide a detailed shaft section model with masses, mass elastic data, shaft section lengths, and inner and outer diameters with rotor dynamic report. 2.4.6.2.3

Delete: “when specified” from first sentence. Transient torsional and stress analysis required.

2.4.6.2.3

Add: This analysis shall be performed for machine trains driven by a synchronous or adjustable speed motor. If not otherwise specified, driven equipment vendor is responsible for analysis.

2.4.7

Bearings and bearing housings

2.4.7.18

Revise second, third, and fourth sentences to read: Bearings shall not be water-cooled.

Add: 2.4.7.22

On high speed synchronous machines, radial bearings on horizontal motors shall be identical on both ends.

2.4.8

Lubrication

2.4.8.1

Add: A pressurized lubrication system shall be used for all 4-pole and 2-pole motors greater than or equal to 2000 hp.

2.4.8.8

Revise to read: If a pressure-lubrication system is specified that is dedicated to the motor that does not comply with API 614, a system complying with this section shall be provided.

2.4.8.8.3

Revise to read: Main oil and standby oil pumps shall be provided. a.

Pumps shall be positive displacement.

b.

Pumps shall be electric motor driven.

c.

Pumps shall be meet requirements of API 676.

d.

Required pump shaft power shall not exceed driver nameplate rating with pump delivering lube oil at relief-valve set pressure and with maximum viscosity expected at minimum allowable oil temperature.

e.

Minimum allowable oil temperature shall be stated in proposal. Downloaded Date: 6/17/2008 10:15:19 PM The latest update of this document is located in the BP ETP and Projects Library

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2.4.8.8.5


f.

Each pump shall deliver required capacity when lube oil is at highest temperature and corresponding minimum viscosity.

g.

Oil rings at motor bearings shall serve as backup protection for motor bearings if electrical power fails.

Revise to read: A separately driven, automatically controlled standby pump shall be provided. Cooler shall be water-cooled, shell-and-tube type. Air cooled type excluded.

2.4.8.8.6

Add: Twin oil coolers shall be provided.

2.4.8.8.7

Add: Twin full-flow filters shall be provided.

2.4.8.8.8

Revise to read: An electric immersion heater with the following characteristics shall be provided. a.

Heater shall be thermostatically controlled.

b.

Heater shall have sufficient capacity to heat oil in reservoir from minimum specified site temperature to minimum start-up temperature within 12 hours. Standard heater would be rated for 4 hour warm-up.

c.

Heater shall have a maximum power density of 15 watts per square inch.

2.4.8.8.10 Add: Orifice plates shall have a diameter of 1/8 inch, minimum. Tubing shall be 3/8” minimum. Add: 2.4.8.8.12 Needle valves shall not be used. 2.4.8.8.13 Bearing lube oil supply pressure, temperature, flow rates, and heat rejection rates shall be provided. 2.4.8.8.14 The following instrumentation and controls shall be provided: a.

Pressure gauges at pump discharge and filter discharge locations.

b.

Temperature indicators for inlet and outlet oil at coolers, as well as for outlet oil from bearings.

c.

Three pressure switches or two transmitters connected to independent taps at the end of lube oil header closest to bearings for 1) auto-start of standby pump, 2) low oil pressure alarm, and 3) low oil pressure shutdown. Separate independent instruments are required for control and shutdown signals.

d.

Filter differential pressure indicator located at the filters.

e.

Filter high-differential-pressure switch located at the filters.

f.

Cooler-discharge-temperature, high-temperature alarm.

g.

Oil-reservoir, low-level alarm.

h.

Oil level site glass.

i.

Hand-Off-Automatic (HOA) switch shall be provided for both pumps.

j.

Switches shall have double-pole double-throw (DPDT) contacts. Downloaded Date: 6/17/2008 10:15:19 PM The latest update of this document is located in the BP ETP and Projects Library

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k.

Individual external relief valves shall be provided for each positive displacement pump. Valves shall function only to protect pumps from overpressure.

l.

Continuous-flow, two-way, six-ported switch valve on each cooler-filter assembly.

m.

Separate, direct acting, back pressure control valve with manual bypass to maintain system pressure by spilling back to reservoir.

n.

Temperature control valve (Amot, or equal) shall be provided for lube oil temperature control.

2.4.8.8.15 Instruments shall comply with the following: a.

Pressure-relief valves for all operating equipment shall meet limiting requirements defined in API RP 520, Parts I and II.

b.

Pressure-relief valves shall be set to operate at not more than maximum allowable working pressure but not less than 110% of rated pressure, or rated pressure plus 25 psi, whichever is greater.

c.

Sizes and set pressures of pressure-relief valves related to equipment shall be provided.

d.

Back-pressure control valve shall be sized such that pump pressure-relief valves do not lift even when both pumps are operating.

e.

Response time for backpressure control valve oil system shall be such that system pressure is maintained if one pump (out of two) is shutdown.

f.

Lube oil control valve shall be in reservoir return line.

g.

Lube oil control valve shall be fail closed.

2.4.9

End play and couplings

2.4.9.3

Revise first sentence to read: If limited-end-float coupling is used, motor shall have a stainless steel nameplate to show the following: a.

Magnetic center reference line.

b.

Total end float of rotor movement before coupling is installed and aligned.

c.

Allowable limits of rotor movement after coupling is installed and aligned.

d.

Reference point.

2.4.10

Materials

2.4.10.1

General

Add: 2.4.10.1.7 Windings and leads shall be constructed of copper. 2.4.10.7

Stator lamination core plate

Add: Core iron shall be tested prior to winding in accordance with EASA Tech Note No. 17. 2.4.11

Nameplates and rotation arrows

2.4.11.3

Revise first sentence to read: Connection diagrams and data nameplates shall be located at associated connection for the following: Downloaded Date: 6/17/2008 10:15:19 PM The latest update of this document is located in the BP ETP and Projects Library

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2.4.11.3.b Revise to read: Space heaters (operating voltage, wattage, surface temperature, and replacement element number). Add: 2.4.11.3.g Oil Heater (operating voltage, wattage, heatup time from minimum ambient temperature, and replacement element number)

Section 3 - Accessories 3.1

Terminal boxes

3.1.1

Revise first sentence to read: Terminal boxes and auxiliary equipment enclosures shall be constructed of cast or nodular iron, cast steel, or steel plate with a nominal thickness of 1/8 inch (3.2 millimeters).

3.1.3

Revise second sentence to read: Terminal box for accessory leads may only be integral to terminal housing if separate access from outside is provided such that main terminal housing access need not be used.

3.1.3

Revise third sentence to read: Termination of leads for instrumentation, heaters, and other accessory items shall be terminated in separate boxes.

3.1.4

Revise second sentence to read: Terminal box shall be suitable for bottom or side entry (drive end) on stator shift machines. For bracket bearing machines the cable entry shall be on the outboard end.

3.1.5

Add: Terminal-box mounting studs shall not be used to secure equipment grounding.

3.1.7

Add: Surge-protection capacitors, isolated capacitor housing per phase, lightning arrestors, and current transformers shall be mounted in a welded-steel power terminal box on motor. Above 5 kV, individual capacitors shall be provided per phase and with separate ground wires.

3.1.8

Add: Current transformers shall be suitable for ambient temperature conditions that may exist in terminal box.

Add: 3.1.12

Main motor terminal box in classified area shall be ventilated from enclosure.

3.1.13

Terminations and interior jumpers shall be insulated.

3.2

Winding temperature detectors

3.2.1.1

Add: Extension leads from RTD wire leads to terminal box shall be 18 AWG. 22 AWG minimum standard.


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3.3

Bearing temperature detectors

3.3.1

Revise first sentence to read: Bearing temperature detectors shall be provided in machines with hydrodynamic radial and thrust bearings in accordance with the following: a.

Motors with hydrodynamic bearings 900 hp and above and below 1500 hp shall have provisions for at least one bearing-temperature device per bearing.

b.

Motors with hydrodynamic bearings 1500 hp and above shall have at least one bearingtemperature device per bearing.

c.

Bearing-temperature devices shall be spring-loaded, tip-sensitive, dual element, three-wireelement platinum RTDs, with a resistance of 100 ohms at 32°F (0°C).

3.4

Space heaters

3.4.1

Revise first sentence to read: Motors shall be equipped with wired space heaters whose leads are brought out to a separate terminal box.

3.4.3

Revise last sentence to read: Surface temperature of heater elements shall be less than 200°C and less than the maximum temperature associated with the applicable T code as defined by NFPA 70 Table 500.8B.

3.5

Screens and filters

3.5.4

Add: Air velocity through filters shall be no more than 600 ft/min.

3.6

Alarms and control devices for motor protection

3.6.4

Synchronizing and control devices

Add: 3.6.4.3

Excitation control units for brushless synchronous motors shall include: a.

Aluminum or anodized/plated steel mounting plate for installation in motor switchgear.

b.

Separate AC control power isolation transformer for the excitation control package for each motor.

c.

A manual exciter field current regulator.

d.

A timing device to delay field application for slow speed applications.

e.

A speed switch capability for high-speed applications.

f.

Exciter field DC voltmeter and ammeter.

g.

A power-factor protective relay with adjustable time-delay feature to deactivate powerfactor relay during motor starting.

h.

A constant voltage transformer when specified if regulation is to exceed +/–10% or if the electronic speed switch is not fed by a regulated 24 volts power supply.

i.

A design to automatically adjust field current to maintain constant power-factor, constant VARs or constant terminal voltage, to a preset, adjustable value.

j.

Manual switch for selecting manual or automatic control mode.


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k.

Power factor relay protection scheme coordinated with supplier, customer, and driven equipment manufacturer to assure protection of amortisseur winding and that mechanical shocks shall be considered in pole-slip instances.

l.

Power Factor or VAR transducers mounted either on same mounting plate as excitation control package or on a separate back-plate supplied by motor vendor and with appropriate drawings, terminal strips etc. to allow mounting by switchgear manufacture.

3.8

Vibration detectors

3.8.1

Revise to read: Fluid-film bearing motors shall be equipped as follows: a.

Motors 900 hp through 2499 hp shall have provisions for mounting two eddy-current shaft proximity vibration probes per bearing.

b.

Motors 2500 hp and larger shall have two radial eddy-current shaft proximity vibration probes and proximitors per bearing, provided in accordance with API 670.

c.

A key phasor shall be provided in accordance with API 670 for motors 2500 hp and larger.

d.

A key phasor shall be provided in accordance with API 670 for gearbox applications.

Section 4 – Inspection, testing, and preparation for shipment 4.3

Final testing

4.3.1

General

4.3.1.5.1

Add: If motor sub-base is provided, vibration tests shall be made with motor mounted on sub-base. Motors furnished without motor sub-base shall be attached to a support having a minimum mass of three times that of motor.

4.3.4

Stator tests

4.3.4.2

Surge test

4.3.4.2.1

Add: For motors over 10000 hp, two randomly selected coils or roebel bars shall be voltage endurance tested per IEEE 1043. If records of previous tests on identical coil designs are available, test results may be substituted in lieu of testing with BP approval.

4.3.4.3

a.

One failure is allowed.

b.

If a second failure occurs, an additional two coils shall be tested.

c.

No failures are allowed in re-test.

Power factor tip up test

Add: On a VPI’d machine, power factor results shall be 2% or better to be acceptable. 4.4

Preparation for shipment

4.4.10

Add: a.

Motor drawings shall indicate bracing and blocking required during shipment.

b.

Instructions for removal of bracing and blocking shall be specified on drawings. Downloaded Date: 6/17/2008 10:15:19 PM The latest update of this document is located in the BP ETP and Projects Library

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c.


Supplier shall determine above deck or below deck shipping if marine transportation is used and prepare shipment accordingly.

Section 6 - Vendor’s data 6.1

Proposals

Add: 6.1.20

For shafts machined from hot-rolled steel, shaft material heat-treating procedure shall be provided with proposal.

6.1.21

Schematic diagram and complete bill of materials for proposed shaft-driven oil-pump lubrication system shall be provided with proposal.

6.1.22

Surge-ring configuration shall be provided with proposal.

6.1.23

A completed, reproducible, and certified copy of a data sheet shall be provided for each motor.

6.1.24

Company shall be advised separately in writing of any changes to data sheet.

6.1.25

A reproducible and certified copy of outline drawings shall be provided for each type (i.e., unique model number and identical features) of motor supplied.

6.1.26

Vendor data shall be identified with project number, purchase-order number, and item/tag number(s).


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GIS 12 206 5 February 2003

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