Hi
I'm in the market for a step-down transformer, (I'm in Australia where voltage is 240 and need to run some small (100W Max) USA appliances) and in my research I am finding the following....
The specs say: This is not dielectrically isolated. What does that mean, and how do I know if I need it to be isolated?.
Cheers
In response to what Spankalogical Protocol posted in news:426b7cb6 snipped-for-privacy@x-privat.org:
It's an auto-transformer - one winding, with centre tap for output.
-- Joe Soap. JUNK is stuff that you keep for 20 years, then throw away a week before you need it.
Your question is very general! It's rather like saying I need a ship; without saying what it is to be used for! Freight or passengers? Some questions to try and narrow down what your requirement is.
1) Step down from 240 to what? Could be anything from 115 volts to 12 or 3 volts!!!!! 2) What is it for. (Could be anything from a heavy electric drill requiring half a horsepower (which I have) to a small handheld electric shaver (that I also have) which requires 7 watts or less. I have transformers for both; the former weighs about 30 lbs and has a handle to lift it. The latter is small enough to put in my pocket! 3) Whether the output of a transformer needs to be electrically isolated from the input is very much a matter of what it will be used for, safety etc. 4) There are several types and ways in which a transformer can be connected. a) A transformer with completely separately connected input (primary) and output (secondary) will most likely need to handle ALL (100%) of the power involved plus any incidental transformer losses. b) An auto transformer will also, normally handle ALL the power involved AND will need windings adequate to carry the heaviest current involved. the tapping points on an auto transformer may or may not be 'centre taps', c) A transformer connected in a voltage-bucking arrangement will most likely only have to handle a certain percentage of the load. Thus it can often be smaller/lighter/cheaper. Give the question some thought and decide if you need a; in equivalent terms for the transformer, a tanker or a cruise ship!If you go to most any major electronics parts supplier, you can order a transformer 240 VAC to 120 VAC. I would get them rated to at least double or more than the load you want, so that they will run cool. These are generaly not very expensive.
If where you are, they are using 50 Hz instead of 60 Hz, this may be critical with some appliances, that are line frequency sensitive.
Jerry G. ======
You should carefully read his question, and use some common sense. If he is running US or North American appliances, you should know that they are rated from 105 to 125 VAC.
You should also consider that a proper transformer for this should be electricaly insulated between the primary and secondary. He also said this, but not in the same words.
-- Jerry G. Not listening or paying attention, displays the same sensitivity as a "toilet seat".
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