UPS1000Z, UPS1200Z, UPS500G and UPS600G Uninterruptible Power Supplies Caterpillar

Description

Illustration 1	g01273590
(1) Transformer T1 (2) Transformer T2 (3) Transformer T3

The left panel of the MMS cabinet consists of the following transformers: T1, T2 and T3.

The transformers are 480 V or 230 V transformers that are used for the power distribution. The transformers convert the utility input voltage to the following DC voltage:

• 190 VDC

• 230 VDC

• 190 VDC and 230 VDC

Transformer T1 (1) is supplied from the bypass voltage. Also, the T1 supplies 190 VDC and the T1 supplies 230 VDC to the PWD.

Transformer T2 (2) is supplied from the output voltage. Also, the T2 supplies 190 VDC and the T2 supplies 230 VDC to the PWD.

Transformer T3 (3) is supplied from the input voltage and the T3 supplies 190 VDC to the PWD.

A thermistor is attached to each transformer on the lower side of the transformer. The thermistor is connected to the H1 connector of the transformer.

The thermistor limits the inrush of current on the power up of the system.

Thermistor Removal Procedure

Refer to Systems Operation, Testing and Adjusting, UENR3954, "Internal Component Preremoval Steps (MMS System Cabinet)" in order to shut down the system and gain access to internal components.

1. Remove the two screws that attach the thermistor to the terminal block.

2. Remove each thermistor from the terminal block.

   Note: One screw is attached to the H1 terminal connector and one screw is attached to the COM or H2 terminal connector.

Installation Procedure

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Illustration 2	g01273627
Wire connections for the transformer

1. Place one lead of the thermistor into the H1 connector. Place one lead into the COM or H2 connector. Refer to Illustration 2.

2. Tighten the two screws in order to attach the thermistor.