UPS 1000S/ UPS 1200S Uninterruptible Power Supplys Caterpillar

Three transformers supply the controllers and auxiliary contacts of the Maintenance Bypass circuit breaker, the Maintenance Bypass Controller Board, the Maintenance Bypass Power Supply Board and other cabinet components.

Transformer (T9) and Transformer (T10) are 480V/230V transformers. Transformer (T9) feeds the Maintenance Bypass Controller Board from the input of the Maintenance Bypass Controller Board. Transformer (T10) feeds the Maintenance Bypass Controller Board from the system output in the System Input/Output Cabinet. Transformer (T11) is a 480V/21V transformer that supplies the Maintenance Bypass Board.

The transformers are installed on a panel on the top right side of the cabinet.

Illustration 1	g01337685
Right Panel (Maintenance Bypass Cabinet) Components (1) Transformer (T9) (2) Transformer (T10) (3) Transformer (T11) (4) Fuse Block F52-F54, F57, F67, F68

The thermistors for Transformer (T9) and Transformer (T11) are located on the upper side of the transformer, as installed. The thermistor for Transformer (T10) is located on the bottom side of the transformer, as installed. All thermistors are connected to the "H1" connector of the transformer.

The Thermistors limit the in-rush of current on power-up.

Table 1

Thermistor Specifications
	Size	Ohm
Transformer (T9)	35mm	10
Transformer (T10)	35mm	10
Transformer (T11)	32mm	20

Table 2

Transformer Specifications
	Input (V)	Output (V)	Wire Gauge (AWG)
Transformer (T9)	380, 400, 415, 440, 480	230	10-22
Transformer (T10)	380, 400, 415, 440, 480	230	10-22
Transformer (T11)	380, 400, 415, 440, 480	21	H=12-22 X=10-18

Thermistor Removal

1. Perform steps in the Systems Operation, Testing and Adjusting, "Internal Component Preremoval Steps (Maintenance Bypass Cabinet)" in order to de-energize the system and gain access to internal components.

2. Loosen the two screws and pull the thermistor free of the terminal block. Each thermistor is attached by two screws to the transformer terminal block. One to the "H1" connector and one to the "COM", or unlabeled connector.

Thermistor Installation

1. Loosen the screw of the "H1" connector and the "COM" or the adjacent unlabeled connector.

2. Place one lead of the thermistor (5) into the "H1" connector and place one lead into the "COM" connector next to the "H1" connector.

3. Tighten the screws to attach the thermistor (5) firmly.

Transformer Removal

1. Perform steps in the Systems Operation, Testing and Adjusting, "Internal Component Preremoval Steps (Maintenance Bypass Cabinet)" in order to de-energize the system and gain access to internal components.

2. Remove all four wires or wire pairs from the transformer by loosening the screws holding the wires in the terminal block.

3. Remove the 4 hex screws at the corners of the transformer that hold the transformer to the cabinet panel. Use a 76 mm (3/16 inch) hex key.

Transformer Installation

Illustration 2	g01273641
MBP Transformers

1. Situate the transformer in position on the right cabinet panel as indicated in Illustration 2.

2. Attach the transformer using 4 hex bolts to the right panel.

   Use a 76 mm (3/16 inch) hex key.

3. Connect the four wires or wire pairs to the transformer.

   Each wire location is labeled. Transformer (T9) and Transformer (T10) will connect with wires labeled "COM". These wires are connected to the underside of the unlabeled connector next to "H1".