9v DC from 3 phase power line

Yes, if the 3 phase power has 240 volts line to line.

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John Popelish
Reply to
John Popelish
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Yes, you can use an adapter with the same primary tension as two of the phases tension. Measure voltage across 2 phases first. Miguel

Reply to
Externet

Thats the usual way here in aus. Transformers with 415 volt primaries aren't too hard to find here, its very common in industrial control. An industrial supply shop should have the transformer you want. If you try and connect a transformer designed for 240 onto 415 volts it will saturate and you will quickly burn it out. If a neutral is present just connect it between an active and neutral. Be careful of colour codes too, machines seem to use a wide variety of colours for various things - black isn't necessarily neutral.

Check the voltage first :)

cheers

Reply to
James

I have a machine with 1kW, 3 phase motor. I also have a sensor board measuring temperature, humidity and rotation speed. This board operates with 9v, 100mA DC. How can I obtain 9v from the 3 phase power line? Can I use any two line of the 3 phase power line to connect an ordinary 240v to 12 v transformer?

Reply to
<Johnietta>

|I have a machine with 1kW, 3 phase motor. |I also have a sensor board measuring temperature, humidity and rotation |speed. This board operates with 9v, 100mA DC. |How can I obtain 9v from the 3 phase power line? |Can I use any two line of the 3 phase power line to connect an ordinary 240v |to 12 v transformer? | Listen only to swanny.....

The fact is that if you measure between ANY 2 PHASES you will read 415 V nominal. If you measure between ANY ONE PHASE and NEUTRAL you will read 240V nominal. Since this is what you require for a readily available wall-wart transformer then that's how you obtain the primary input voltage for the wall-wart.

Reply to
Ross Herbert

rotation

ordinary 240v

The above seems to originate in Australia where there is almost universally 3phase Y connected 230/400 volt supplies. In a motor situation there may not be a handy neautral but general purpose power is always 230 volts phase to neautral and the only trnsformers (Wall Warts) readly avaiable are 230 to whatever. Of course it may be expedient to buy a special transformer with a 400 volt primary if there is no neautral at the actual location this 9 volts is required.

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John G

Wot's Your Real Problem?
Reply to
John G

If you have to ask that, you shouldnt be doing any such thing!

Reply to
Howard Latham

bust out one of the phases and neutral. you can run this to the appropriate transformer with some filter caps in front of and behind a

7809 voltage regulator ic. any of the phases to neutral will be about 120vac but if you go across 2 phases then the voltage goes up to about 208vac or so be careful

Howard Latham wrote:

Reply to
carl

Reply to
carl

Whilst no doubt you could make it work in that manner (Aus supply being 415v phase to phase) it would not be a good method. Far better to have a seperate supply for the monitoring eqt. I am assuming that the motor runs off an outlet ?? If it has a control cabinet or motor starter cubicle then mounting the tranny with a fuse in the supply line would be the best approach.

-- Regards ........... Rheilly Phoull

Reply to
Rheilly Phoull

Reply to
carl

2
415v

seperate

Oh OK now I understand.

-- Regards ........... Rheilly Phoull

Reply to
Rheilly Phoull

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