Star delta connection
Working Principle of Star-Delta Starter This is the reduced voltage starting method. Voltage reduction during star-delta starting is achieved by physically reconfiguring the motor windings as illustrated in the figure below. During starting the motor windings are connected in star configuration and this reduces the voltage across each winding 3. This also reduces the torque by a factor of three.
Scheme - Working Principle of Star-Delta Starter
After a period of time the winding are reconfigured as delta and the motor runs normally. Star/Delta starters are probably the most common reduced voltage starters. They are used in an attempt to reduce the start current applied to the motor during start as a means of reducing the disturbances and interference on the electrical supply. The Star/Delta starter is manufactured from three contactors, a timer and a thermal overload. The contactors are smaller than the single contactor used in a Direct on Line starter as they are controlling winding currents only. The currents through the winding are 1/root 3 (58%) of the current in the line. There are two contactors that are close during run, often referred to as the main contractor and the delta contactor. These are AC3 rated at 58% of the current rating of the motor. The third contactor contactor is the star contactor and that only carries star current while the motor is connected in star. The current in star is one third of the current in delta, so this contactor can be AC3 rated at one third (33%) of the motor rating.
Size of each part of Star-Delta starter
1. Size of Over Load Relay
For a star-delta starter there is a possibility to place the overload protection in two positions, in the line or in the windings . Overload Relay in Line:
In the line is the same as just putting the overload before the motor as with a DOL starter. The rating of Overload (In Line) = FLC of Motor. Disadvantage: If the overload is set to FLC, then it is not protecting the motor while it is in delta (setting is x1.732 too high). Overload Relay in Winding:
In the windings means that the overload is placed after the point where the wiring to the contactors are split into main and delta. The overload then always measures the current inside the windings. The setting of Overload Relay (In Winding) =0.58 X FLC (line current).
Disadvantage: We must use separate short circuit and overload protections. 2. Size of Main and Delta Contractor
There are two contactors that are close during run, often referred to as the main contractor and the delta contactor. These are AC3 rated at 58% of the current rating of the motor. Size of Main Contactor= IFL x 0.58
3. Size of Star Contractor
The third contactor is the star contactor and that only carries star current while the motor is connected in star. The current in star is 1/ √3= (58%) of the current in delta, so this contactor c an be AC3 rated at one third (33%) of the motor rating. Size of Star Contactor= IFL x 0.33
Motor Starting Characteristics of Star-Delta Starter
Available starting current: 33% Full Load Current. Peak starting current: 1.3 to 2.6 Full Load Current. Peak starting torque: 33% Full Load Torque.
1. Standard Size of Transformer (IEEE/ANSI 57.120) Single Phase Transformer
Three Phase Transformer
5KVA, 10KVA, 15KVA, 25KVA, 37.5KVA, 50KVA, 75KVA,
3KVA, 5KVA, 9KVA, 15KVA, 30KVA, 45KVA, 75KVA,
100KVA, 167KVA, 250KVA, 333KVA, 500KVA, 833KVA,
112.5KVA, 150KVA, 225KVA, 300KVA, 500KVA, 750KVA,
1.25KVA, 1.66KVA, 2.5KVA, 3.33KVA, 5.0KVA, 6.6KVA,
1MVA, 1.5MVA, 2MVA, 2.5MVA, 3.7MVA, 5MVA, 7.5MVA,
8.3KVA, 10.0KVA, 12.5KVA, 16.6KVA, 20.8KVA, 25.0KVA,
10MVA, 12MVA, 15MVA, 20MVA, 25MVA, 30MVA,
33.33KVA
37.5MVA, 50MVA, 60MVA, 75MVA, 100MVA
2. Standard Size of Motor (HP) Electrical Motor (HP) 1, 1.5, 2, 3, 5, 7.5, 10, 15, 20, 30, 40, 50, 60, 75, 100, 125, 150, 200, 250, 300, 400, 450, 500, 600, 700, 800, 900, 1000, 1250, 1250, 1500, 1750, 2000, 2250, 3000, 3500 and 4000
3. Approximate RPM of Motor HP
RPM
< 10 HP
750 RPM
10 HP to 30 HP
>600 RPM
30 HP to 125 HP
500 RPM
125 HP to 300 HP
375 RPM
4. Motor Line Voltage Motor (KW)
Line Voltage
< 250 KW
>440 V (LV)
150 KW to 3000KW
2.5 KV to 4.1 KV (HV)
200 KW to 3000KW
3.3 KV to 7.2 KV (HV)
1000 KW to 1500KW
6.6 KV to 13.8 KV (HV)
5. Motor Starting Current Supply
Size of Motor
Max. Starting Current
1 Phase
< 1 HP
6 X Motor Full Load Current
1 Phase
1 HP to 10 HP
3 X Motor Full Load Current
3 Phase
10 HP
2 X Motor Full Load Current
3 Phase
10 HP to 15 HP
2 X Motor Full Load Current
3 Phase
> 15 HP
1.5 X Motor Full Load Current
6. Motor Starter Starter
HP or KW
Starting Current
Torque
DOL
<13 HP (11KW)
7 X Full Load Current
Good
Star-Delta
13 HP to 48 HP
3 X Full Load Current
Poor
Auto TC
> 48 HP (37 KW)
4 X Full Load Current
Good/ Average
0.5 to 1.5 X Full Load Current
Excellent
VSD
Motor > 2.2KW Should not connect direct to supply voltage if it is in Delta winding
7. Impedance of Transformer (As per IS 2026) >MVA
% Impedance
< 1 MVA
5%
1 MVA to 2.5 MVA
6%
2.5 MVA to 5 MVA
7%
5 MVA to 7 MVA
8%
7 MVA to 12 MVA
9%
12 MVA to 30 MVA
10%
> 30 MVA
12.5%
. Standard Size of Transformer Standard Size of Transformer
KVA
Power Transformer (Urban)
3, 6, 8, 10, 16
Power Transformer (Rural)
1, 1.6, 3.15, 5
Distribution Transformer
25, 50, 63, 100, 250, 315, 400, 500, 630
\
Electro pneumatics
PLC
Fire alarm
Security System / Burglar Alarm - Sample DSC Alarm System This guide uses the DSC Power 864 security system with DSC accessories as an example to detail exactly how to wire a security system. Actual wiring diagrams and pictures are provided for real DSC products. This guide assumes that all of the components will work together. See the Alarm Wiring guide for more information. This is the master wiring diagram for a Power 864 main panel. The Power 864 supports 64 different zones, but only 8 zones are available with the main board. Additional boards would have to be purchased to expand t his system. This panel contains connections for power, the siren, keypads, devices, and sensors. Each will be covered in detail below.
DSC PC 5020 - Power 864 Panel Click for full size image
Power Wiring
The power connections consist of the AC power and the backup battery. Note that I am working from the left to the right on the circuit board, but the power should be the last thing you connect.
For this alarm system, the wires for the battery come directly out of the side of circuit board. First, verify that the power requirements of the circuit board match those of the battery. In this case, they should both be 12 volt 7 amp-hours. Buying the recommended BD7-12 battery or purchasing the battery, power supply, and main board in a kit is easier. The wire colors will be red & black which match perfectly the red and black terminals on the battery itself. Connect the ground first (black), and then the power (red). Using 18 AWG or better wire, measure the length of wire needed to connect the power supply at the power outlet to the power terminals on the circuit board. First connect the wires to the power supply, then the wires to the alarm panel, and then finally plug in the power supply to the electrical outlet. The power supply will either have 2 screw terminals (+, -) or 3 terminals (+, -, ground). Typically, both the power supply and alarm panel will have power connections labeled + and -. Connect the + terminals together and the - terminals together. Usually your power wire will be colored, labeled with + or -, or will have a stripe (for power) to differentiate the positive and negative wires. For this alarm, the ground is located at the opposite end of the circuit board. You could run the ground from the ground connector on the power supply and it will work since this ground will run back to the electrical box and then to the building's main ground. I prefer to tap directly into the building's main ground. This is easy for me because my wiring panel (which is only a couple of feet from the electrical box) already has a direct ground connection for other wiring. Tapping the building's main ground normally means clamping a wire to the copper water pipe as a
ground or connecting it to a driven ground rod. There is no need to figure this out for yourself. Your home should already have a VERY thick wire that is clamped to this ground connection and run to the electrical box. Also, any coaxial cables for cable TV or satellite will also be grounded right as they enter the home and you can either leverage that ground or trace it back to the grounding clamp. Finding a good ground is another good reason to locate the alarm panel with other wires in a basement or utility closet. The alarm system also recommends that you also ground the metal alarm panel box. This is done in case a power wire comes lose and contacts the cabinet. With the cabinet grounded, that lose wire will be grounded in case it comes in contact with the cabinet. To ground the cabinet, connect a ring connector to the end of the ground wire. Then, cut another short length of wire and connect a ring connector to one end of that wire. Using one of the existing holes in the cabinet (alarm panel box), bolt both wires to the cabinet as indicated above: bolt, cabinet hole, star washer, long ground wire to building ground with ring connector, lock washer, nut, short ground wire with ring connector, lock washer, nut. For this specific alarm system, all of these parts were included in the kit. Note: The star connector is required to scratch the paint off of the cabinet. Paint doesn't conduct electricity. Note that there is a hole located at the top of the power supply housing. If your w all outlet has a screw in the middle of the wall plate, then you can remove that screw, plug the power supply into the bottom outlet, and then put the screw through the hole in the top of the power supply and back through the wall plate. This prevents the power supply from falling out of the outlet or someone removing it by mistake. Also make sure you don't use an outlet that can be turned off by a wall switch.
Bell Wiring
The siren/horn/bell for the system basically makes lots of noise when the alarm goes off. As before, if the siren didn't come as part of a kit, then verify that the siren doesn't draw too much current for the panel, in this case no more than 700 milliamps. This means that the siren must be labeled 700 mA or less.
The siren will either have + and - terminals or black (-) and red (+) wires coming out of it. Connect these wires to the black and red wires of the alarm wire that runs back to the + and - bell terminals on the main panel. For this example, the siren also has an optional yellow (+) wire that can be used instead of the red wire. Using the yellow wire makes a yelp noise and the red wire makes a steady tone.
Keypad Wiring
Keypads typically require 4 wire connections. For multiple keypads, run each wire from the keypad back to the control panel and simply place multiple wires in each connection. The terminals on the keypad are labeled Z G Y B R. The G (Green), Y (Yellow), B (Black), and R (Red), are the standard 4 colors for alarm wiring. The DSC Z model keypads contain a 5th Z connection that can be used to monitor an additional zone. Remember that the Power 864 panel supports up to 64 zones but only has connectors for 8. The sensor wiring description below details how to use the Z terminals.
Device Wiring
The Device terminals are for smoke detectors and other programmable devices. Below are the instructions for wiring 2 or 4 wire smoke detectors to a DSC alarm. Consult your alarm manual for any specific instructions on wiring programmable devices.
Sensor Wiring
All sensors use the COM (common) Z connectors on the control panel circuit board. Powered sensors (Ex: motion detectors) also require the + & - auxiliary power connections. All 4 COM connectors on the board are identical and a ny of the can be used. The idea is that Z1 & Z2 use the first COM terminal, Z3 & Z4 use the second... At the alarm panel side, connect the wires using the colors shown below. Door and window sensors don't require Aux Power, so don't connect the red and black wires. You may be tempted to connect these wires when unused just to get t hem out of the way. That is a bad idea, because it means there will be live +12V power at the other end of that wire. A short could cause the alarm to malfunction or a short could damage the circuit board.
Panel Connector Color
Powered Sensor
Door/Window
Connector
Sensor
Z
Green Normally Closed (NC) Either wire
COM
Yellow Common (C)
Aux +
Red
Power (+12V)
Either wire
Aux -
Black Ground (GND)
Below are sample DSC sensors: Motion Detector, Glass Break Sensor, Window Sensor, and a Door Sensor. Specifics for wiring each type of device follows. Be sure to read our sections on Alarm Wiring and Tamper Proof Wiring before you do any wiring yourself.
Non-powered sensors like door and window sensors come in 2 parts. The first has 2 wires or 2 connectors on it that connect to the green and yellow wires from the alarm panel. It doesn't matter which wire goes to which connector. The second part of the sensor contains a magnet. It is best to wait to permanently mount the second part of the sensor until the alarm system is running and you are able to verify proper placement.
The motion detector above and the glass break sensor below use all 4 wires. The extra 2 wires are for power. As indicated in the control panels diagram, the power draw for all powered devices (including sensors) cannot exceed 550mA. As and example, this motion detector can draw up to 20mA and the glass break sensor can draw 32mA so there is pleanty of headroom for many sensors.
The Normally Closed (NC) connections are preferred over Normally Open (NO) ones. Cutting a wire to a NC sensor will set off the alarm while cutting a wire to a NO sensor will disable that sensor. This glass break sensor also includes a tamper connection that can be wired as a separate zone or in series with the Normally Closed contacts. Wiring the tamper circuit to the alarm will activate the alarm when the cover of the sensor is removed.
Phone Wiring
The phone connection is required so that the alarm system can call the alarm monitoring company when the alarm goes off. Even if you are not
paying for monitoring, you will want to make the phone connection. Otherwise, the control panel will detect this missing connection as a problem and the Trouble light on the alarm w ill stay lit. If you have an phone outlet available, the easiest way to make the phone connection is to take a spare phone wire and cut off one of the ends. Then strip the wires and connect the cut end to the control panel. Otherwise, run the wire from the alarm panel to any phone wire you can find in the basement and make the connection there. Pin
Use
Alarm Color Standard Phone Wire Color Cat3/Cat5e Color
1
Green Stripe
2
Line 2 Tip Brown
Black
Orange Stripe
3
Line 1 Ring Red
Red
Blue
4
Line 1 Tip Green
Green
Blue Stripe
5
Line 2 Ring Gray
Yellow
Orange
6
Green
The phone wire colors on this alarm (at least for Line 2) don't match standard phone wire colors. Also, in new homes many builders use Cat5e cable for phone wire. It is easier and cheaper to buy one large spool of Cat5e cable and use it for both internet and phone lines. Your own phone wires can be any color. Just make sure that you match up the correct colors when using different types of wires.
Disclaimer This model of burglar system was chosen because it is one that I am personally familiar with and I had parts and manuals that were available for review. These instructions are provided as an example for how to interpret instruction manuals for different alarm systems so that you will have a better understanding of them. It is not intended that you blindly wire an alarm system exactly as described above. Small changes to the
control panel or components may occur over time, so always reference the manual that came with your hardware before this site. Also, please review the disclaimer on our Structured Home Wiring home page. This example is not intended as an endorsement of DSC and this site is not affiliated with DSC. DSC (Digital Security Controls Ltd.) is a division of Tyco International.
INTRODUCTION. The purpose of this article is to show you how to terminate and assemble Keystone RJ-45, RJ-12, and miscellaneous jacks. DESIGN. Pre-planning is essential so that your installation goes smooth. Keystone Wall Plates with 1, 2, 3, 4, and 6 positions are available as well as Surface Mount Boxes with 1 & 2 positions. It is a good idea to leave a unused position in Wall Plates for future expansion. You can use a blank insert to cover up the unused position. Keystone Inserts are available for RJ-45 (Network), RJ-12 (Telephone), F (Cable TV COAX), BNC (Video Coax), RCA (Audio and Video), SVHS (Video), Banana Binding Posts (Speakers), ST ( Fiber Optic), and Blank to cover unused positions in Wall Plates or to make your own custom insert.
Examples of RJ-45 Keystone Jacks
Step 1. Strip The Cable
Trim the jacket of the cable back approximately 1 inch (Caution: Do not damage conductors). If you nick them, cut the cable off and start again. Fan out all four twisted pairs. Note: It is designed for use with solid conductor premise cable.
Step 2. Align The Wires In the Slots
Following the instruction of the color-coded wire positions printed on the jack, lay the conductors into the punch down slots. Depending on the manufacturer, the connections may look different than the one shown. Some connections will be at 90 degrees of the jack (like the one shown) and others are straight out the back of the jack. Keep pairs twisted as close to the punch down slots as possible. They must be twisted within 1/2" to conform to Cat 5 specifications.
Standard Wiring for RJ45 Jack (Jack face shown)
Step 3. Terminate The Wires In The Slots
The RJ-45 Jack Inserts are self terminating. A plastic header cover is included that is snapped down over the connector and provides a secure connection. Make sure that the wires are in the proper slot. Press the plastic header down over the wires until the header
bottoms out on the top of the terminal. On some Inserts, the header is hinged on the back of the Insert and others are actual separate plastic parts.
Specific Termination Notes Front View Top View
Position wires in the slots. Press the plastic terminal header over the terminals which will press the wires into the slot. Make sure that the header is pressed all of the way down against the terminal. . Front View Rear View
Position wires in the slots. Press the plastic terminal header over the terminals which will press the wires into the slot. Make sure that the header is pressed all of the way down against the terminal. . Front View Rear View
Position wires in the slots. Press the hinged plastic cover down over the wires until it snaps. This will push the wires down into the slots. Then press the small plastic lock down into the slot behind the clear plastic hinged cover. This locks the cover down.
Step 4. Install Insert into Wall Plate
Carefully install the Insert into the Wall Plate hooking the bottom latch first and then pushing up on the Insert, engaging the upper latch.
Frequently Asked Questions Wiring Standards
Q.
T568A and T568B wiring: what’s the difference, and how do I know which one to use?
A.
T568A and T568B are the two wiring standards for an 8position modular connector, permitted under the TIA/EIA568-A wiring standards document. The only difference between T568A and T568B (also known as Weco, AT&T 258A) is that the orange and green wire pairs (pairs two and three) are interchanged.
Standard 4-Pair Wiring Color Codes Pair 1
T R
White/Blue Blue/White
Pair 2
T R
White/Orange Orange/White
Pair 3
T R
White/Green Green/White
Pair 4
T R
White/Brown Brown/White
Note: For 6-wire jacks use pair 1, 2 and 3 color codes. For 4-wire jacks, use Pair 1 and 2 color codes.
How to decide which wiring pattern to use: 1. Does the job specification call out a wiring pattern? 2. Does the customer/end user have a preference for T568A or T568B? 3. Have patch panels already been purchased for the job? If so, hey will probably be either T568A or T568B. The jacks should be wired to the same pattern as the panels. 4. Are you adding on to an existing wiring plant? If so, your new
wiring should match the existing wiring. If none of the factors above apply, either T568A or T568B m ay be used. It is important to ensure that the workstation connectors and he patch panels are wired to the same pattern. T568B is commonly used in commercial installations, while T568A is prevalent in residential installations.
Q.
A.
hat’s the difference between 110 connections and 66 connections?
Both 66 and 110 blocks are insulation displacement connection (IDC) devices, which are key to reliable data connections. 66-clip blocks have been the standard for voice connections for many years. Although 66-clip blocks historically have been used for data, t hey are not an acceptable connection for Category 5 or higher cabling. The 110-type connection, on he other hand, offers: (A) higher density (more wiring in a smaller space) and (B) better control (less movement of the wires at the connection). Since more and more homes and businesses call for both voice and data connections, it is easy to see why it makes sense to install 110-type devices in most situations.
Typical 110 Punch Block
Typical 66 Punch Block
Q.
What does RJ mean?
A.
RJ stands for Registered Jacks. These are telephone and data jacks or applications registered with the FCC. Numbers like RJ-11, RJ-45, etc. are widely misused in the telecommunications industry. They are not actually jack types. A much more precise way to identify a jack is to specify the number of positions (width of opening) and number of conductors. For example: "8-position, 8conductor jack" or "6-position, 4-conductor jack".
Q.
How do I wire a one- or two-jack telephone wallplate to my telephone wiring if the plate has solid color wires and my house has striped wires?
A.
See the illustration below for wire color cross-compatibility.
Caution--if you encounter "Quad" wire (four non-twisted wires) on the premises, take note: Quad wire is no longer acceptable for installation in multi-line environments. Quad's lack of pair twisting makes it susceptible to interference. If encountered during a retrofit, quad wire should be replaced with 100 ohm UTP (unshielded twisted pair). Connecting new quad to installed quad will only amplify existing problems and limitations associated with quad wire; leaving existing quad in place and connecting 100 ohm UTP to it may also be ineffective, as the quad wire may negate the desired effect of the UTP.
Q.
A.
hat is the Category Rating System?
In the mid 1980’s, companies representing the elecommunications and computer industries were concerned
with the lack of a standard for building telecommunications cabling systems. In response to that concern, the Electronic Industries Association (EIA) developed a standard called TIA/EIA-568-A. One of the sections of that standard was the definition of performance categories for 100-ohm UTP horizontal cabling. Level 1 This category consists of basic telecommunications and power-limited circuit cables. There are no electrical performance est or bandwidth requirements for this classification. Level 1 cabling may not be used in horizontal cabling systems. Level 2 This category consists of cables specified to 1 MHz. Level 2 cabling may not be used in horizontal wiring cabling systems. Category 3 This is a performance designation for twisted-pair cable and connecting hardware that can support f requency ransmission up to 16 Mhz, and data rates of 10 Mbps. Category 3 has the capability to support low speed data applications, performing to the acceptable minimum for 100 ohm cabling systems; however it is now primarily used for telephone wiring. Category 4 This category consists of cables and connectors specified up to 20 Mhz and data rates of 16 Mbps. Since the development of Category 5, however, Category 4 wiring systems are rarely used. Category 5 This category consists of cables and connectors specified up to 100 Mhz and data rates of 100 Mbps, providing optimal performance for all data and phone systems. These systems are quickly becoming the standard because they provide a "safety net" to help ensure that current and future high-speed applications will run with peak accuracy, efficiency and throughput.
®
Q.
How do I wire a QuickPort jack?
A.
Leviton Voice & Data has three different connectors. Two are wired the same way: the Category 5 Power Sum connector and the TM GigaMax connector. See the diagram below for wiring directions: TM
The eXtreme connector is a proposed Category 6 connector and is wired differently. Follow these general directions to terminate all three types of connectors: 1. Strip 2" of cable jacket and position first pair according to color code. The center channel lets you preserve wire twisting to less than .5" from the termination point.
2. Set 110-tool to low impact setting and turn cutting edge outward to terminate first pair. The patented ‘cutting ledge’ trims the wire as you terminate, saving you a step.
3. As with the first pair, position and terminate each subsequent pair one at a time until termination is complete.
4. Snap on strain relief caps. The connector is now ready to be snapped into any QuickPort® housing or wallplate.
To view a Diagram, click on a wiring pattern below. (Note: to retain detail, these graphic sizes are large, allow time to download.)
Q.
hat’s the difference between a keyed jack and a non-keyed jack?
A.
Modular, non-keyed 8 position connectors accept standard (non-keyed) 8 position patch cords Modular, keyed connectors accept both keyed and non-keyed 8-position patch cords. A k eyed connector is shaped to accommodate the keyed male plug, which has a small, square notch on its end. A keyed plug will not fit into a female nonkeyed connector. Unless a keyed connector is called out in a specification, it is usually assumed the parts needed are non-keyed.
Q.
What is UTP Cable?
A.
UTP stands for "unshielded twisted pair". It is a cable type with one or more pairs of twisted insulated copper conductors contained in a single sheath. It is the most common type of cabling used in desktop communications applications.
Q.
Why should I use home run or star topology wiring as opposed to daisy chain wiring?
A.
A Star Topology has been defined as the standard for horizontal cabling in accordance with TIA/EIA-568-A. Star Topology calls for workstations to be wired directly to a central equipment hub that establishes, maintains and breaks connections between workstations. When a star topology is used, it is much easier to locate and isolate wiring problems than it is with daisy chain wiring. The most common means of star wiring is a telephone PBX.
