UPS 120, UPS 150, UPS 250, UPS 300, UPS 301, UPS 500, UPS 600, UPS 750 and UPS 900 Uninterruptible Power Supplies Caterpillar

Rotor Position Sensor - Adjust

Note: Adjustment of the rotor position sensor is necessary upon initial start-up. Calibration of the sensor gap is necessary whenever the Comm/Accel board is replaced and whenever the top bearing of the flywheel is replaced.

Note: A dial caliper is required to perform the following procedure.

Illustration 1	g01273214

1. Measure the depth that is from surface (1) to surface (2). Record the depth.

2. Measure the depth that is from surface (1) to surface (3). Record the depth.

   Note: This measurement must be taken from the top of the tooth on surface (3).

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   Illustration 2	g01273216
   (1) Surface 1 (2) Surface 2 (3) Surface 3

3. Subtract the distance in step 1 from the distance in step 2. Record the results.

4. Measure the distance that is shown in Illustration 3. Record the distance.
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   Illustration 3	g01273231

5. Measure the distance that is shown in Illustration 4. Record the distance.
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   Illustration 4	g01273233

6. Subtract the distance in step 5 from the distance in step 4. Record the results.

7. Subtract 0.2540 mm (0.0100 inch) Record the results.

8. Subtract the results in step 7 from the results in step 3. Record the results.

   Note: The Rotor Position Sensor (RPS) Gap is formed from the results of the calculation that was performed.

   This distance should be between 0.7620 mm (0.0300 inch) and 1.0160 mm (0.0400 inch).

9. Remove the two screws (4) in order to adjust the Rotor Position Sensor (RPS) Gap. Remove shims (5) under the board in order to increase the gap. Add shims (5) under the board in order to decrease the gap.

Illustration 5	g01273292
(4) Screw (5) Shim

Illustration 6	g01273294
(4) Screw (5) Shim

Note: The thickness of the shims can be 0.1270 mm (0.0050 inch) or 0.2540 mm (0.0100 inch). Measure the thickness of the shims before relocating.