Cummins/Onan — Testing Exciter Stator, Exciter Rotor, Main Rotor and Main Stator Windings
Testing & diagnosis · generator windings
From a Cummins/Onan service manual — check it applies to your exact model before use.
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Procedure
- Measure winding resistance with a Wheatstone bridge or digital ohmmeter; replace the component if not as specified in Table 5-1.
- Disconnect the leads and measure insulation resistance between any lead and the laminations using a megger (600 VAC or less).
- Replace the component if insulation resistance is less than 1 megohm (1,000,000 ohms).
- On the main rotor, torque the terminals to 24 in-lbs when reassembling.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- 1 megohm
- 24 in-lbs (2.7 Nm)
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.