1990/08/06 Caterpillar

SR 4 Generators With 580 And 680 Frame Sizes

SUPPLEMENT: 03/23/92

SERVICE MAGAZINE; August 6, 1990; Page 19; "Rotor Shaft Length Changed" For SR4 Generators With 580 And 680 Frame Sizes.

Disregard this article. Make reference to a new article with the same title in this issue.

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The 580 and 680 frame sizes of SR 4 Generators have two different lengths of main rotor shafts. A change to improve the heat sink assembly resulted in a longer main rotor shaft. However, a change in part number identifying the longer shaft did not coincide with the change in length. The chart gives the serial numbers of the generators that were manufactured with the longer main shaft, and the corresponding exciter assembly.

This change in shaft length affects the servicability of the excitor rotor and heat sink assembly for generators manufactured prior to the serial number listed in the chart. If these units experience a main rotor failure they may be serviced in the following manner.

When the short main rotor shaft is replaced with the longer shaft, a new heat sink and exciter assembly are needed. In addition to main rotor assembly (7), the following hardware is required:

1 - 9Y5976 Spacer (Inner) (1)

1 - 5N5003 Spacer (Outer) (2)

4 - 0S1591 Bolt (3)

1 - 7E6560 Heat Sink Assembly (4)

1 - 7E6561 Sleeve (5)

1 - 7E7072 Exciter Rotor (6)

NOTE: Part number of the exciter rotor depends on the generator frame size. See chart.

Location of components.

Serviceability for other components on units manufactured prior to the serial numbers may be found in the Service Manual.