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Home›Repair guides›Kohler›Voltage Regulator Board Calibration

Kohler — Voltage Regulator Board Calibration

Adjustments

From a Kohler service manual covering: 10RMOY, 15RMOY, 15RMY, 15ROY, 17.5ROY, 22.5ROZ, 22.5RZ, 24ROZ, 32.5ROZ, 32.5RZ, 47.5ROZ. Check it applies to your exact model before use.

Applies to: Kohler 15RMY, Kohler 15ROY, Kohler 17.5ROY, Kohler 22.5ROZ, Kohler 22.5RZ, Kohler 24ROZ, Kohler 32.5ROZ, Kohler 32.5RZ, Kohler 47.5ROZ

Before you start

  • High voltage is present at regulator board P1 connector and terminal strip when set is running.
  • Do not exceed 285 Volts when adjusting Pot. 2; regulator board damage may result.

Procedure

  1. Disconnect generator from load; place main switch OFF and lift enclosure cover.
  2. Check wire jumpers on regulator board and arrange per Table 3-1/3-2 (J1, J2, J3).
  3. For single-phase connection, lift lead V9 from controller board terminal strip and insulate.
  4. Adjust external voltage adjustment potentiometer to approximate midpoint of range.
  5. Connect AC voltmeter and frequency counter between leads V7 and V8.
  6. Break adjustment seals on Pots. 1, 2 and 3.
  7. Turn Pot. 1 full clockwise and Pot. 2 full counterclockwise.
  8. Start generator set with no load.
  9. Adjust Pot. 2 (Volt Adj.) for the specified output voltage.
  10. Observe LED; if flickering, alternately adjust Pot. 3 and Pot. 1 until steady glow.
  11. Perform overvoltage shutdown check and adjustment (Pot. 6) per 50/60 Hz limits.
  12. Perform overspeed shutdown check and adjustment (Pot. 5) per 50/60 Hz limits.
  13. On NFPA models, check voltage adjustment range (at least ±10 Volts).
  14. Seal Pots. 1, 2 and 3 with insulating varnish.

Tools required

  • AC voltmeter, 0-300 V AC, ±0.5% Amazon
  • Frequency counter, 45-75 Hz, ±1% Amazon
  • Potentiometer adjustment tool or small blade screwdriver Amazon
  • Load bank (for boards with Pot. 4 — Load Shed) Amazon

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

Specs & values

  • 50 Hz overvoltage: 257 ±5 V AC check, ±3 V AC adjust
  • 60 Hz overvoltage: 280 ±5 V AC check, ±3 V AC adjust
  • 50 Hz overspeed: 60 ±2 Hz check, 61 ±1 Hz adjust
  • 60 Hz overspeed: 70 ±2 Hz check, 71 ±1 Hz adjust
  • Do not exceed 285 Volts when adjusting Pot. 2

Full service-parts list: Kohler 15RMY →, Kohler 15ROY →, Kohler 17.5ROY →, Kohler 22.5ROZ →, Kohler 22.5RZ →, Kohler 24ROZ →, Kohler 32.5ROZ →, Kohler 32.5RZ →, Kohler 47.5ROZ →

Source: Kohler 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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