Mains power: how to create a neutral?
Hi
I've a strange main, 3x220v.
When I put a phase tester in the wall plug, both indicate phase.
Good or not, every toroid hums here...
I have read that a phase can be recreate by converting AC to DC (rectifier) and then back to AC (converter).
Sounds weird for the rookie I'am...
Any advice?
Thanks
Hi
I've a strange main, 3x220v.
When I put a phase tester in the wall plug, both indicate phase.
Good or not, every toroid hums here...
I have read that a phase can be recreate by converting AC to DC (rectifier) and then back to AC (converter).
Sounds weird for the rookie I'am...
Any advice?
Thanks
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You have 3 phase AC apparently, common in some domestic installations in Germany and Belgium if not elsewhere. (I lived in a place in the 1970s in Brussels that had it, no problems with buzzing transformers, but toroids weren't a thing then.)
Not sure why you would want an AC regenerator, and not sure it would address your noisy toroids either. (I suppose if your mains were heavily clipped toroids might buzz and there it could help.)
Mechanically isolating the toroids might be more effective if the noise couples into the chassis.
Not sure why you would want an AC regenerator, and not sure it would address your noisy toroids either. (I suppose if your mains were heavily clipped toroids might buzz and there it could help.)
Mechanically isolating the toroids might be more effective if the noise couples into the chassis.
Then if you have conventional 3-phase system you should measure around 220 VAC between any phase and neutral and 380VAC between any pair of phases. I suspect your neutral wire may have too high impedance and as the result high potential difference to protective earth. This can explain why your tester showing both wires as phase.
For many years now the voltages are changed.We had 220V and the UK 240V ,then along came Euromadness, now everyboddy is supposed to get 230V.If it is comming in as a star there is 3x 230V in respect to a center conductor and 400V between fases.Can also come in triagle with 3x230V between fases and no centre.
Transformers from the US intended for 60Hz are no good here with 50Hz.They overheat and buzz.
Mona
Noise almost always means the core is saturating. This can be from what is called DC on the AC which actually means the peak voltage is not the same positive and negative although the average value is still zero.
The test for this is to use two diodes in series and one across them wired the other way. This if inserted in the AC line will either reduce the buzz or increase it. If it increases it then turn the diodes around.
A simple incandescent light bulb in series with the AC main if glowing slightly will drop the voltage a bit and that should reduce the noise if the issue is line voltage and frequency.
The fix is to use a buck transformer. Wire a 220 to 24 volt transformer with the secondary in series with the primary and use that as an auto transformer to buck the voltage. (Be sure to get the phasing between windings right.) When you have the buzz it also means you have magnetic flux leakage greatly increased.
The test for this is to use two diodes in series and one across them wired the other way. This if inserted in the AC line will either reduce the buzz or increase it. If it increases it then turn the diodes around.
A simple incandescent light bulb in series with the AC main if glowing slightly will drop the voltage a bit and that should reduce the noise if the issue is line voltage and frequency.
The fix is to use a buck transformer. Wire a 220 to 24 volt transformer with the secondary in series with the primary and use that as an auto transformer to buck the voltage. (Be sure to get the phasing between windings right.) When you have the buzz it also means you have magnetic flux leakage greatly increased.
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You have an older distribution system with 230V between phases and no explicit neutral.
Between any of the mains sides and the ground you should measure ~132V (be careful doing that measurement).
Your mains might also be unbalanced and polluted, but that's an entirely different story
Thanks for the light ;-) So seems "normal" over here...sh**
I will try to measure it and let you know.
About balanced main, I tried to use a balanced transformer, but so humming.....
About pollution, I tried "power filter" and didn't change a lot. But there is perhaps something wrong elsewhere, even if the house is not so old...
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