Facts About Generators
GeneratorsDirectoryCompareRepairEnginesControllersPartsManufacturersGuides
Search models or part #
Home›Repair guides›RESISTOR ^9°^

Generac — RESISTOR ^9°^

For these Generac models: NP and IM Series, NP/IM.

Applies to: Generac Np And Im Series

Before you start

  • At the time thie Manual was written, all NP/IM
  • The FAN & RING GEAR ASSEMBLY (Item 25) Is
  • Before attempting to measure Insula­
  • that the engine speed governor be properly
  • Field boost current la available to the Rotor only
  • RV AND IM TYPE GENERATORS PRO­
  • OUS
  • OUS AND

Procedure

  1. During operation, unregulated AC current from the Stator
  2. Remove the four capscrews, lockwashers and flatwashers
  3. Remove the Rear Bearing Carrier GASKET (Item 18).
  4. Disconnect wires from BRUSH HOLDERS (Item 16).
  5. Remove SCREWS (Item 17) that retain the BRUSH HOLD­
  6. Remove hardware that retains the Rear Bearing CARRIER
  7. Remove the four long CAPSCREWS (Item 21), along with
  8. A REAR BEARING CARRIER PULLER tool Is available.
  9. Free the STATOR ASSEMBLY (Item 14) from the
  10. Remove the hardware that retains the STARTER (Item 40)
  11. Remove all fasteners that retain the BLOWER HOUSING
  12. Remove CAPSCREWS (Item 33) that retain the FLEX
  13. Remove the ROTOR ASSEMBLY (Kern 1) with the FAN
  14. Remove CAPSCREWS and LOCKWASHERS (Items 34
  15. If the FAN & RING GEAR is to be removed from the
  16. Open the generator’s main circuit breaker. NO ELECTRI­
  17. Disconnect Wires No. 4 from the Voltage Regulator.
  18. Provide an external source to blow warm, dry air through
  19. Start the generator and iet it run for 2 or 3 hours.
  20. Stop the engine and retest Stator and Rotor insulation for
  21. Volt-Ohm-Milliammeter or VOM
  22. Frequency Meter
  23. Insulation Resistance Tester
  24. Load Bank- will permit a known electrical load to be applied
  25. A 4-Pole Rotor must be operated at 1800 rpm to supply a
  26. A 2-pole Rotor must be operated at 3600 rpm for a 60 Hertz
  27. For Units Rated 120/240 Volts at 60 Hertz: Set AC
  28. For units rated 110/220 volts at 50 Hertz: Set AC fre­
  29. Shut the generator engine down.
  30. Connect a voltmeter to the generator’s AC output
  31. Disconnect Wires No. 4 and 1 from the Voltage Reg­
  32. Connect a jumper wire from terminal #1 (Wire #15) of
  33. Connect a jumper wire from terminal #2 of the engine
  34. Start the generator and let It run at no-load (main
  35. Read the generator’s AC output voltage from the
  36. Shut the generator down.
  37. Reconnect Wires No. 1 and 4 to the Voltage Regulator.
  38. Voltage and frequency are both good. If this is the case,
  39. Voltage and frequency are both high or bw, usually an
  40. Voltage is low, but AC frequency is good. The cause of
  41. Voltage and frequency read "zero".

Tools required

  • PULLER
  • PULLER
  • PULLER
  • gauge
  • wrench

Source: manual:Generac Service Manual.pdf. Figures and steps are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.