Greetungs All, I have a small generator (700 watt, 850 surge) that I use to keep the fridge running when the power is out. It is a robust unit made by Robin and is at least 20 years old. It has an accurate analog voltmeter on it. I tested it by comparing to a digital meter and by directly connecting just the meter to the 115 volt, 60 Hz mains. The label says that the generator puts out 60 Hz but when checked with an oscilloscope (TEK 465B) it shows about 50 Hz. Even though the fridge seems to run fine it sounds different than when operating from the mains. The meter on it shows the voltage as being 115 volts and the motor is running at the nameplate RPM. So what could be the reason for the 'scope showing the lower Hz and is there anything I can do about it? This generator uses brushes on a slip ring to energize the field winding and has some type of transistorised voltage regulator. Thanks, Eric R Snow
- posted
17 years ago