Generac — Constant Excitation Test
Testing & diagnosis · Rotor/excitation circuit
From a Generac service manual covering: 9049-0, 9254-0, 9254-1, 9260-0, 9260-1, 9260-3, 9340-0, 9340-1, 9340-3, IM100G, IM80G, NP100G…. Check it applies to your exact model before use.
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Procedure
- Shut generator engine down.
- Connect voltmeter to generator AC output leads.
- Disconnect Wires No.4 and 1 from voltage regulator.
- Jumper terminal #1 (Wire #15) to Wire #4 terminal.
- Jumper terminal #2 (Wire #0 ground) to Wire #1 terminal.
- Start and run at no-load rated speed.
- Read AC output; should be about one-half rated voltage.
- Shut down; reconnect Wires No.1 and 4.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- About 40-60 volts line-to-neutral or 80-120 volts line-to-line
Source: Generac 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.