Thanks,
Presumably the attached two mains input current waveforms to the heater are perfect, and would cause no problem in the mains supply system?
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Flicker limits according to IEC 61000-3-3 must be observed.
…Thanks
https://www.emcstandards.co.uk/files/61000-3-3__-3-11_voltage_fluctuations__flicker.pdf
….Thanks FvM, because from page 9 of the above, I see that this way of controlling heaters (by burst firing the mains) is likely to always be illegal. Do you agree?
Though the whole thing seems to be based on flicker of highly inefficient filament lamps….which are widely illegal anyway….so why are flicker laws still so tight? Why aren’t flicker regulations relaxed?
Supposing that a heater has a burst fire duty of skipping one mains cycle every six mains cycles………..and then suppose that by coincidence, every single customer on that phase, possibly 100’s of users, also had their heater on the same burst fire duty…and suppose by coincidence that they were all synchronized…then its possible to see how the mains voltage level could be a bit up and down. But how would this be damaging to any other equipment on that phase?…..we already appreciate that it could cause flicker in highly inefficient filament lamps, but they are illegal anyway.
Are these flicker laws simply irrelevant to today’s situation?
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The thing is , we don’t see big mains fluctuations anyway even when people all use 16Kw Electric showers at the same time every morning, so I really cant see how we would see widely undulating mains voltages as a result of electric heaters burst firing.
This looks like a case of an irrelevant regulation on flicker, wouldn’t you agree?
The flicker laws clearly arise form the 19th century when lamps used to flicker when carbon lamps malfunctioned due to inadequate maintenance……..so really, this regulation on flicker needs updating surely? …..and burst fire heaters are realistically no problem whatsoever?