Help needed in Australia with transformer problem

HI there I'm not at all knowledgeable about electrics but need help.... I have a small fishpond pump requiring a feed from our 240v supply of
24 volts. My old transformer,which burnt out when my wife accidentally shorted it (I'm blaming her because it's true -- a gardening incident!) gave output of 24 v at 2.5 amp at 60VA. I keep the tranformer in a waterproof shed and there's a 12-metre cable-run to the pond. I have seen an old but working transformer for which the only info I have is that it gives out 24 volts, at 10 amp. No mention of VA. I guess the higher amperage doesn't matter... My prob is that while I could take a punt on that transformer, it might be better to get one which is actually rated like the one I had. And no supply shops in my vicinity (Blue Mountains of NSW) can offer anything at a reasonable price (ie under say $70). I could buy an entire new pump and transformer set for $110 but that seems a waste -- I did see a transformer for $35 at a supply shop in Lithgow which had a suitable rating, but it was for professional electricians only as there was absolutely no indication on it of which of the multiple in- and-out power tags should be cabled to. Hope this mundane query doesn't annoy the experts out there, but I have found the newsgroups a great source of info in the past - and I've been able to help others in different areas of expertise many times... Best wishes, Anthony. For emailing, just strip out the nospam from the addresss.......
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The replacement transformer should be ok. The current rating is the curent that the transformer is ABLE to deliver if needed. Just check that the replacement unit is indeed just a transformer with AC output and not a powr supply that puts out DC rather than AC. Give it a good look over for damage etc before you use it - there maybe a reason it s lying around.
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Also at least check that the Primary winding is wound seperate to the secondary winding, ie. there are 2 "Bobbins or Coils" on the tranny(Like 2 doughnuts on top of each other). This is a safety factor and strictly speaking the tranny should be made to a code. I would be inclined to connect one of the output 24v terminals to earth to provide protection in the event of the tranny developing a short between windings which would be remote if it has the 2 "Bobbins".
Regards ........ Rheilly P
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anthony has brought this to us :

This could be what you are looking for... http://www.jaycar.com.au/productView.asp?ID=MP3045&CATID &formΚT&SUBCATIDQ5 There is a Jaycar in Penrith...I know...it's a long trek. They do sell mail order tho.
Another option is a lighting shop that carry outdoor lighting. They would stock 24 volt supplies.
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Hi, any 24 V transformer with an amperage equal or greater than the amperage you need would be OK... It goes without saying that the primary must be 240 V. The VA rating comes from multiplying Volts time amperes. As for the transformer without nomenclature, the thin wires are the rpimary, while the thicker are for the secondary. If you don't feel confident, get a consumer grade tranformer, and I think it would be a good idea, to fuse the primary, with a simple trip fuse. HTH,
--
Tzortzakakis Dimitrios
major in electrical engineering
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anthony wrote:

The new transformer you have is 240VA. It will work fine, though core loss will usually be a bit higher for a larger transformer, and if you go too far up in capacity, the output under low load may float a bit high.
If you have a transformer without labels on the terminals, you can figure it out pretty easily with a multimeter, the 240V primary winding will have a significantly higher resistance than the secondary.
On this side of the pond there are plenty of electronics surplus dealers , any of which would have this sort of thing, is there anything like that over there?
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Many thanks for all the advice -- I think it should be plain sailing from hereon in, and my wife's fountain should soon be restored! I'll try the transformer I mentioned first, and if that's not suitable, I'll venture forth to the wilds of Penrith....
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"Many thanks for all the advice -- I think it should be plain sailing from hereon in, and my wife's fountain should soon be restored! I'll try the transformer I mentioned first, and if that's not suitable, I'll venture forth to the wilds of Penrith...."
You might want to pick up a 5 amp fuse and hold at an auto supplies store so that "next" time, you just have to replace the fuse rather than the transformer.
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