Caterpillar — Winding - Test
Testing & diagnosis · Generator windings
From a Caterpillar operator's manual covering: C27, C32, SXC1-Up. Check it applies to your exact model before use.
Applies to: Caterpillar C32, Caterpillar C27 engine, Caterpillar C32 engine
Before you start
- High voltage can cause severe injury or death
Procedure
- Place engine control switch in OFF; tag all starting controls.
- Disconnect batteries or disable the starting system.
- Disconnect the winding being tested from other components.
- Measure resistance of exciter armature L2 (less than 0.1 ohm).
- Measure main armature L4 (less than 0.1 ohm) and pilot exciter L5 (less than 0.1 ohm).
- Measure exciter field L1 (approximately 3.0 to 6.0 ohms) and main field L3 (approximately 1.25 to 2.0 ohms).
- Confirm no continuity to ground and no continuity between windings.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Exciter field L1 ~3.0-6.0 ohms
- Main field L3 ~1.25-2.0 ohms
- Armatures less than 0.1 ohm
Full service-parts list: Caterpillar C32 →
Source: Caterpillar operator'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.