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Home›Repair guides›Cummins/Onan›Polarizing the Generator Field

Cummins/Onan — Polarizing the Generator Field

Maintenance · Field windings

From a Cummins/Onan owner's manual covering: 1.5UF-232S, 10.0UF-150S, 12.0UF-3S, 12.0UF-4S, 15.0UB-150S, 15.0UF-3S/104, 2.0UF-125S, 2.0UF-232S/32, 2.0UG-1S/135, 2.5UF-1S, 2.SUD-IS, 2.SUD-IS/ID…. Check it applies to your exact model before use.

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Procedure

  1. Connect an AC voltmeter across the generator output.
  2. Run the generator in the desired direction.
  3. Touch battery positive cable to generator field lead F1.
  4. Touch battery negative cable to generator field lead F2.
  5. If voltmeter shows no voltage build-up, use a larger battery or higher DC source.

Tools required

Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.

Source: Cummins/Onan 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.

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