Detroit Diesel — Exciter Field Test Procedure
Testing & diagnosis · Exciter field winding
From a Detroit Diesel service manual — check it applies to your exact model before use.
Before you start
- Hazardous voltage. Operate the generator set only when all guards and electrical enclosures are in place.
Procedure
- Place master switch to OFF/RESET.
- Disconnect starting battery, negative lead first.
- Disconnect the FP/FN leads.
- Check exciter field resistance with an ohmmeter across FP and FN leads.
- Megohmmeter test: apply 500 V DC to FP or FN lead and exciter field frame; replace if less than ~500 kOhms.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Good insulation reading approximately 500 kOhms (1/2 megohm) and higher
Source: Detroit Diesel 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.