Friday, October 23, 2009

Gallopin' Generator

I have a Generac generator. When I turn on the air conditioner inside the motorhome and the load increases, the engine begins trying to maintain the voltage by increasing the RPMs. It over-compensates and then begins decreasing RPMs. It repeats this for six or seven cycles while the voltage ranges from 105-volts to 128-volts. This all takes place in about 20 seconds, and then it evens out and holds a steady 117-volts. Is this harmful? If so, any suggestions?
Barry, (Westlake, LA)


Barry, typically when a generator surges or “hunts” for the correct setting during the application of loads, it is usually the governor that needs adjusting. The governor adjustment controls the frequency of the output voltage and can calm an accelerating/decelerating situation. However, the carburetor must first be adjusted correctly prior to making any adjustments to the governor. Here’s the catch; every adjustment on the carburetor and governor, however slight they may be, will have an electrical result that you will not be able to detect audibly. It must be monitored electrically by using a load bank designed specifically for setting up RV generators. The load bank will enable a technician to apply a rated load at varying intervals while monitoring the frequency and the voltage at the same time. Generators cannot be tuned by ear. 

Search for a shop in your area with the appropriate equipment. Without a load bank, a technician would simply be guessing, and yes, such surging and rapid fluctuation of the frequency and voltage can be damaging to some electrical equipment in the RV.