Re: Measuring half wave voltages on Valve Testers.
Some years ago I looked into why a VCM mkIV was giving odd readings and it turned out to being used in a part of the factory with a very badly distorted mains waveform with flat topping and phase synchronous spikes and rings. There was about 2MW going into fluorescent strip lighting and electronic equipment (no PFC) and a machine shop on the floor below with lots of phase-controlled variable speed drives.
I ran it from 50Hz from an HP 651A wien bridge oscillator and a huge 2kW 'Elgar' amplifier/mains simulator and all was well.
The other thing distorted waveform does is change the amount of heat delivered by the heater.
Bad mans waveforms aren't a factory thing, modern housing areas are rather bad too, especially as less and less of the base load is resistive. All these energy efficient bulbs and smart motors are usually below the power level where PFC becomes compulsory, but there are now so many of them....
David
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Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done
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