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240v supply from 415V ?

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BodgeIt

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Mar 24, 2010, 2:51:32 PM3/24/10
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I have an electrical panel supplied with 415V, 3 phase and earth, no
neutral. I need to have a 240v powered switch mode PSU installed in
the same panel. Can it be done without a neutral?

Thanks

cynic

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Mar 24, 2010, 3:57:34 PM3/24/10
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I suggest a 400/230 volt transformer to power the PSU. You may need to
earth one leg of the 230 volt output to provide a neutral depending on
the requirements of the PSU.

Dave Osborne

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Mar 24, 2010, 4:11:17 PM3/24/10
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Yes, but you would need to buy a 415v/230V transformer.

An autotransformer will do and may be cheaper than an isolating
transformer, but you are more likely to get 415V to 110V, so check if
your switch mode is dual voltage.

If the power is 50VA or less, you could use eBay item 170461492064

link to eBay: http://preview.tinyurl.com/ycnas4d

Connect the primary of the transformer between any two 415V phases with
a 2-phase MCB, e.g. http://www.tlc-direct.co.uk/Products/CM9806D.html

BodgeIt

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Mar 25, 2010, 6:45:19 AM3/25/10
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Thanks for your advice, I hadn't even thought about a step down
transformer having got so focused on going across a phase and my non
existent neutral.

Cheers

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