Caterpillar SR4B — Generator Set Functional Test
Testing & diagnosis
For the Caterpillar SR4B, from the Caterpillar service manual.
Applies to: Caterpillar SR4B
Before you start
- Do not exceed half rated speed
- Do not allow output to exceed nameplate rating
Procedure
- Disconnect wires F1 and F2 from voltage regulator
- Disconnect generator load
- Connect 12 VDC battery to wires F1+ and F2-
- Operate generator at half rated speed
- Measure AC voltage across terminals T1-T2, T1-T3, T2-T3
- Record voltages at half speed, then at ±10% speed variations
- Verify minimum 85 VAC output at half speed
- Verify speed changes produce proportional voltage changes
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Output minimum 85 VAC
- Speed sensitivity ±10%
Full service-parts list: Caterpillar SR4B →
Source: Caterpillar service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.