Caterpillar — Generator Winding Insulation - Test
Testing & diagnosis · Generator main stator winding
From a Caterpillar owner's manual covering: 3508, 3512, 3512B, 3516, 3516B. Check it applies to your exact model before use.
Applies to: Caterpillar 3508, Caterpillar 3512, Caterpillar 3512B, Caterpillar 3516, Caterpillar 3516B
Before you start
- High voltage can cause electrocution. Discharge instrument leads and generator windings.
Procedure
- Take the generator out of service.
- Visually inspect generator for moisture. If moisture exists, dry the unit first.
- Inspect installation. Determine equipment that will be tested.
- Discharge capacitance of the windings. Disconnect 'T0' from ground.
- Disconnect sensing lead wires for regulator and PT leads of load share module.
- Connect insulation tester Black lead to ground; RED lead to 'T0'.
- Set voltage to rated voltage. Apply voltage; observe readings at 30 and 60 seconds.
- Record 60 second reading (correct for temperature), temperature, and humidity.
Tools required
- 300-8648 Insulation Testing Gp Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Use 30/60 Time Resistance Method
- 50 percent reduction from previous reading may indicate moisture
Full service-parts list: Caterpillar 3508 →, Caterpillar 3512 →, Caterpillar 3512B →, Caterpillar 3516 →, Caterpillar 3516B →
Source: Caterpillar owner's 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.