If you were to put an oscilloscope across the power output of our generators, you would see that there is a lot of "noise" on the nominal sine-wave waveform. That's essentially because of the voltage regulator electronics doing its thing. It's that "noise" that confuses the heck out of a cheap multimeter.
When I read for frequency on a non RMS meter at 11 and 44 connections at the main output breaker on my new model 5884 generator while generator is running of course, the meter for a second or two reads the correct frequency of 60Hz. The reading then jumps to over a hundred. When reading line power frequency in the house the meter reads 60Hz and does not vary. Is this because of the electromagnetic interference at the point of a running generator? Where are the best points to read for frequency from the generator power? Thank you for any clarification. :confused:
It would make no difference where the measurement is made along the power wiring. In other words, proximity of the meter to the generator is not the source of the problem.
I have never had a problem reading the frequency of my generators when using Fluke meters that are rated as reading "True RMS" values on AC measurements.