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Generac — Voltage Regulator Adjustment

For these Generac models: QUIETPACT 55, QUIETPACT 65, QUIETPACT 75.

Applies to: Generac Quietpact 55, Generac Quietpact 65, Generac Quietpact 75

Before you start

  • NOTE: If, for any reason, sensing voltage to the regulator is lost, the regulator will shut down and excitation output to the Rotor will be lost. The AC output voltage will then drop to a value that is commensurate with Rotor residual magnetism (about 7-12 VAC). Without this automatic shut-down feature, loss of sensing (actual) voltage to the regulator would result in a full field or full excitation condition and an extremely high AC output voltage.
  • NOTE: Adjustment of the regulator's VOLTAGE ADJUST potentiometer must be done only when the unit is running at its correct governed no-load speed. Speed is correct when the unit's no-load AC output frequency is about 62.5 Hertz. At the stated frequency, AC output voltage should be about 124 volts.

Procedure

  1. 1. Set the frequency to 62.5 Hertz with no load on the generator.
  2. 2. Slowly turn the voltage adjust potentiometer on the voltage regulator until 124 VAC is measured.
  3. 3. If voltage is not adjustable, proceed to Section 6 - Troubleshooting; Problem 2.

Specs & torque values

  • Target output voltage: 124 VAC
  • Frequency setting: 62.5 Hertz
  • No-load condition required

Source: manual:0E7225.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.