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| Illustration 1 | g01277295 |
Controls Cabinet Back Panel (29) Customer Contacts Interface Board #2 (Optional) (30) DC Bus Pre-charge Circuit Resistors (31) T1 - T4 Transformers (32) Power Supply Board (PWS) (33) Customer Contacts Interface Board #1 (34) Power Supply Board (PWS) (35) Thermistor (36) Fuse F69 (37) Fuses F88-F90, F70-F72 (38) Zig-Zag Transformer (39) K7 Pre-charge Contactor (40) K6 Pre-charge Contactor | |
The Power Supply Board in the Controls Cabinet supplies unregulated control power to all boards in the UPS1200 system.
The input to each Power Supply Board is 21VAC. The voltage is rectified into unregulated dc. Each Power Supply Board has isolated and redundant rectifiers located on the same board. These rectifiers are paralleled through diodes in order to prevent a filter capacitor failure in one power supply to cause a failure in the other supply. Each power supply has a normally closed dry contact output in order to indicate to the APC2 that the power supply is correct.
The PWS-1 also supplies the 24VDC to the UVR coil of the input breaker.
A control relay and capacitor time constant are also located on the power supply as well. This circuit supplies power to the input breaker for up to 5 seconds after an outage at which time the breaker will open.
Fuses
The type and function of the fuses are indicated in Table 1. Visually inspect the fuses. Replace the fuse if the fuse is blown.
| Power Supply Board Fuses | |
|---|---|
| Fuse | Type |
| PWS-F1 | 30 A |
| PWS-F2 | 30 A |
| PWS-F3 | 250VAC, 3.15 A, Time Lag |
| PWS-F4 | 250VAC, 3.15 A, Time Lag |
Removal
| NOTICE |
|---|
Electrostatic discharge can damage integrated circuits or semiconductors if you touch bus connector pins. When not in use, keep the module in the static-shield bag. Follow these guidelines when you handle any module: Touch a grounded object to discharge static potential. Wear an approved wrist-strap grounding device. Do not touch the bus connector or connector pins. Do not touch circuit components inside the module. If available, use a static-safe work station. |
- Perform steps in the Systems Operation, Testing and Adjusting, "Internal Component Preremoval Steps (Controls Cabinet)" in order to de-energize the system and gain access to internal components.
- Disconnect all connectors from the board.
The connectors have a label that indicates the location of the cable in the unit. Verify each connector to make sure that the label is present and legible. Refer to Illustration 2.
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| Illustration 2 | g01278255 |
Power Distribution Board | |
- Remove the cross head screw from the bottom right corner of the board.
- Disconnect the seven white plastic stand-offs connecting the board to the left panel using the following method.
Note: The board must be removed from the stand-offs without bending the board.
- Pinch the head of each stand-off so that the board is not locked to the stand-off but is still attached to the stand-off.
- Remove the board by gently and evenly pulling the board from all stand-offs at the same time.
Installation
| NOTICE |
|---|
Electrostatic discharge can damage integrated circuits or semiconductors if you touch bus connector pins. When not in use, keep the module in the static-shield bag. Follow these guidelines when you handle any module: Touch a grounded object to discharge static potential. Wear an approved wrist-strap grounding device. Do not touch the bus connector or connector pins. Do not touch circuit components inside the module. If available, use a static-safe work station. |
- Position the board in the cabinet over the seven white stand-offs that are connected to the left panel.
- Push the board, gently and evenly, onto all the stand-offs simultaneously. Make sure all stand-offs are locked in place.
- Attach the cross head ground screw to the bottom right corner of the board.
- Plug the wire connectors into the correct connectors on the board. Check the labels on each connector for proper placement.
Refer to Illustration 2.