Cummins/Onan — Exciter Voltage Test - Bench Test (Auxiliary Power)
Testing & diagnosis
From a Cummins/Onan service manual covering: 02SX1N1A, 04SX1N, 04SX1N1A, 04SX1N1B, 04SX1N2B, 04SX1N3B, 04SX1N4B, 06SX1N, 06SX1N1A, 06SX1N1B, 06SX1N2B, 06SX1N3B…. Check it applies to your exact model before use.
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Procedure
- Connect Variac to exciter terminals E1 and E2 as shown in Figure 5.
- Connect an AC voltmeter to these same terminals E1 and E2.
- Connect DC voltmeter to field leads F1 and F2.
- Connect a 100 watt light bulb across these same terminals F1 and F2.
- Adjust Variac until voltage reaches value shown in column 2 according to exciter model.
- DC voltage should now be within limits shown in column 3 (Table 4-2).
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Source: Cummins/Onan 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.