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Home›Repair guides›Generac›Stator Insulation Resistance Test (12-20 kW)

Generac GT-530 — Stator Insulation Resistance Test (12-20 kW)

Maintenance

For the Generac GT-530, from the Generac service manual.

Applies to: Generac GH-410 engine, Generac GT-530 engine, Generac GT-990 engine, Generac GT-999 engine

Before you start

  • Do not apply voltage longer than one (1) second.
  • Electronic components can be destroyed if subjected to high megger voltages.

Procedure

  1. Disconnect stator output leads 11 and 44 from the main line circuit breaker.
  2. Remove stator output leads 22 and 33 from neutral connection and separate the leads.
  3. Disconnect Wires 11 and 22 from Voltage Regulator; ensure not touching other components.
  4. Connect terminal ends of Wires 11, 22, 33 and 44 together, isolated from frame.
  5. Connect red Hi-Pot test probe to joined leads; black tester lead to clean frame ground.
  6. Set Hi-Pot voltage selector to 1500 volts; turn tester ON and observe breakdown lamp.
  7. DO NOT APPLY VOLTAGE LONGER THAN 1 SECOND; then turn tester switch OFF.
  8. If breakdown lamp comes on, clean and dry stator, repeat test; replace stator if it fails again.

Tools required

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

Specs & values

  • Test power setting 500 volts when testing stators or rotors
  • Minimum insulation resistance formula: (GENERATOR RATED VOLTS / 1000) + 1 megohms

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.

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