Author Topic: isolation transformers  (Read 220 times)

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Offline Paul M0BSW

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isolation transformers
« on: December 11, 2016, 02:41:41 PM »
Hi Everyone,

I want to build a isolation transformer unit, here in the UK we have a spine chilling 240v line voltage, so far I haven't found a 1:1 transformer, so could I use 2x 240 to 50v transformers, use one as a step down and one as a step up, any thoughts on this, I  can't really have a go at a tube radio restoration until I've built a isolation transformer unit.
Paul    de m0bsw

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Re: isolation transformers
« Reply #1 on: December 11, 2016, 03:18:20 PM »
That would be an interesting concept Paul. Don't think I have seen one built like that.
Will look that up.
Buddy kc4umo

Offline k7rmj

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Re: isolation transformers
« Reply #2 on: December 12, 2016, 12:56:31 AM »
Hi Paul. I have seen this done before and it does work. Be certain to connect the phasing of the primary versus secondary windings the same for both transformers. Connect the two 50 volt secondary windings from your two transformers to each other. One of the primary windings, transformer #1 plugs into your 240 volt power outlet. The other primary winding, transformer #2 will give you the 240 volts you are looking for. Whatever you do, be careful. That is a lot of voltage.
Good luck.
Frank  de K7RMJ

Offline Paul M0BSW

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Re: isolation transformers
« Reply #3 on: December 12, 2016, 02:10:43 AM »
Hi Frank, Yes I have a very healthy respect for our 240 volts, why in the modern  world it has to be so high is beyond me. It's that fear which has stopped me working on the old tube radio I have, I do use a variac most of the time, however a isolation transformer is a must I feel.

Paul  de M0BSW