UPS 1000S/ UPS 1200S Uninterruptible Power Supplys Caterpillar

Illustration 1	g01281569
Inverter Thermistor Location (1) Inverter Thermistor

Illustration 2	g01281571
(1) Inverter Thermistor

The thermistor is located on the upper left panel of the Inverter Cabinet below the five neutral bus fuses. The thermistor is used to measure temperature at the top of the cabinet.

The thermistor is attached to the Inverter Cabinet General Purpose Interface Board that is located on the left panel of the cabinet.

Signals from the thermistor are digitized by the General Purpose Interface Board and sent to the APC2 Board in the Controls cabinet.

Removal

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

2. Loosen the thermistor from the bracket connected to the upper left panel.

3. Cut the tie wraps holding the blue and black wires to other cabling in the cabinet to the General Purpose Interface Board ("J3") connector.

4. Detach the thermistor from the "J3" connector on the General Purpose Interface Board.

Installation

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Illustration 3	g01281574
(1) Inverter Thermistor (2) Blue Wire to GPI Board ("J3") () Black Wire to GPI Board ("J3")

1. Attach the new thermistor to the upper left panel with one cross head screw.

2. Attach tie wraps to the cabling to fix it in place down to the General Purpose Interface Board.

3. Attach the end of the thermistor wiring to the "J3" connector on the General Purpose Interface Board located on the lower left panel.