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Topic Title: Transformers
Topic Summary: short circuit on the output
Created On: 07 June 2010 07:51 PM
Status: Post and Reply
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07 June 2010 07:51 PM
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eswnl

Posts: 144
Joined: 29 November 2008

Hi

On a transformer (such as the ones for reducing 240V to 100V so you can operate U.S appliances in the UK), I was wondering what happens if the output is shorted. Does the the current flowing into the primary increase and thus blow the fuse in the 13amp plug?

It would be better if there was a fuse on the output side as US plugs don't have a fuse inside.
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08 June 2010 06:18 PM
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ArthurHall

Posts: 721
Joined: 25 July 2008

The current in the primary will increase up to a point when it will be limited by the transformer impedance.
I would still recomend a fuse on the secondary side.
Are you making this unit? If so remember to make sure the outgoing neutal is earthed.
Also remember America is 60Hz and Europe is 50Hz so any motors will run slower.
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09 June 2010 02:01 AM
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eswnl

Posts: 144
Joined: 29 November 2008

Originally posted by: ArthurHall

The current in the primary will increase up to a point when it will be limited by the transformer impedance.

I would still recomend a fuse on the secondary side.

Are you making this unit? If so remember to make sure the outgoing neutal is earthed.

Also remember America is 60Hz and Europe is 50Hz so any motors will run slower.


No, I'm not making anything. I have a 200W 240-100V transformer bought commercially. This has a fuse on the casing, presumably for the output side.
But I saw another 240-100V transformer which was rated at 45W which had no fuse.

Is it to do with the difference in power?
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10 June 2010 06:37 PM
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iqbalkhan

Posts: 38
Joined: 26 January 2009

Hi
As ArthurHall said it is quite correct just to add
if you shorted the secondary then there will be a full rated current with 0 impedence .In addition to we use fuses to protect the windings and loads even I hand made few extension electrical leads by hand using components available i use fuse to protect it is slow but a good and cheap protection .
Better not to try the SC the sec windings

cheers
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