20-10-2017, 02:41 PM
(20-10-2017, 01:34 PM)Kalee20 Wrote:(19-10-2017, 11:31 PM)Refugee Wrote: A moving iron meter made to work on 50Hz will not give a useful reading at any other frequency.
You will need something else to measure it.
It should do, actually. It may be problematic at 10Hz and below, due to needle vibration - coming Ok again at DC, obviously.
However, 22kHz is pushing it, and I can see winding shunt capacitance, and eddy currents, all conspiring to make it read less than it should. It depends what you mean by 'useful reading'. Can you use an audio amplifier, signal generator, and a light-bulb load, to give an idea of calibration change with frequency?
I have a feeling that the amount of time and trouble would be beyond the scope of a quick measurement.
You would need to use a pretty hefty square wave generator to make up a calibration chart.
An audio amp would work for sine waves and would be a lot less useful for calibrating a meter that is going to measure square waves.
