Saturday, November 5, 2011

How to built safe Isolation Transformer?

Its not easy, but if you are technical and have proper electrical knowledge on working with meter and circuit boards, then you can built it with waste junk box.
Well when we must service or otherwise work on a TV or similar device that has a "Hot Chassis" or we just want to work "Above Earth" then we need an Isolation Transformer, this device protects us from lethal shock, and put's the unit being worked on, as we say "Above Earth" this way when we use our instruments, such as a 'scope etc, it will not "Blow the Fuses nor trip the breakers" when we take a measurement. So one can outlay a considerable expense and purchase one, but if one only uses it infrequently then this may be an unnecessary expense, it may be better to "Roll your own" to do this we simply obtain Two suitably rated step down power transformers say 12 V AC to 110 or 230 V AC or whatever is applicable to your country, or whatever secondary voltages you have at hand it doesn't matter as long as BOTH are the same. Now simply connect them up back to back, meaning that we connect the 12 V secondary windings to each other, observe polarity with regards to the windings.Then connect one of the Primary's windings to a suitable mains rated cable and Male Plug, the other Primary windings end we attach a Mains Socket, so we can plug in our "To be serviced equipment" into, DO NOT use an Earth. (If one makes a metal case for it all, it will NOT hurt to put the earth from the mains cable IN, to the case though) This then will Isolate us & the equipment from the earth, and provide us with a secure and safe power supply for us to use when servicing, there you are it's just that simple. Also ensure that the transformers you use are rated high enough to provide the current required to allow your units to be serviced to work, so anything over say a couple of Amps on the secondary side will be fine, simply upscale it for anything bigger. 
As an aside here too we can also use the 12 V secondary, as a power supply too, one can even rectify it and smooth for a 12 V DC supply, it could even be made switchable in range for other voltages too, real handy sometimes, all built in to your mains Isolation Transformer.
This above mentioned details will help you to make safe isolation transformer.

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