What is the purpose of this transformer? (Pic)

Jez · 24 Feb 2013 at 11:24

http://dl.dropbox.com/u/27289822/transformer.jpg

What is the purpose of this transformer?

For context, this is inside an illuminated heated bathroom mirror, the transformer is fed via a normal 230v feed from the mains, and outputs to a 230v shaver socket mounted on the side of the mirror housing.

So it receives 230v, and outputs 230v?

Reason i ask, it buzzes like hell, can i just loop it out? I dont see what it is actually doing.

What gives? :confused:

Jez · 24 Feb 2013 at 11:34

dan^uk said:
is there a 110v/230v switch?

No switch, shaver socket is 230v only. The black thing on the right is the shaver socket itself, just fed via the two blue feeds from the transformer secondary.

Jez · 24 Feb 2013 at 11:35

Malt_Vinegar said:
I think its to limit the current?
I say leave well alone!

Cosimo said:
Looks like current reduction.

So we think its just as a current limiter in case a faulty device should be plugged into the shaver socket?

Jez · 24 Feb 2013 at 11:37

Malt_Vinegar said:
Think about where you use a bathroom mirror...
Usually right over a sink.
A current limiter is a sensible idea.

Hmm, it is right above a sink

Perhaps given the isolation transformer link above this is also part of the IP rating of the mirror?

Jez · 24 Feb 2013 at 11:43

OK. All makes sense, very useful thread for me, thanks

Jez · 24 Feb 2013 at 11:52

Jokester said:
IP rating is just a measure of how dust/water tight something is, so the transformer won't have anything to do with it.

The socket is exposed though?

IP aside i can see the safety aspect. I wont just loop it out as i guess in theory that would create an unswitched 6A socket right above the sink.

Jez · 24 Feb 2013 at 11:59

The socket is mounted to the side of the unit, exposed on the outer edge to allow things to be plugged into it. You can see the socket to the right hand side, it is the black rubber covered device.

Jez · 24 Feb 2013 at 12:26

neodude said:
It's an isolation transformer. It isolates the output circuit from the input.

Because the output voltage is not referenced to Earth or Chassis Ground theoretically this means that you cant get an electric shock by grounding one of the outputs, which is how you would usually get a shock. The only way you would get a shock is by shorting both output terminals of the secondary coil.

Also as stated above there is the current limiting effect. Being shocked by a secondary coil that can only provide 500mA is better than being shocked by a mains circuit that can provide 5A.

Excellent explanation, thanks for that. Completely understand it now, and will not bypass it as the feed is on a 6A breaker and a direct 6A socket above the sink is probably not clever.

mattyg said:
Two options

French polish
Nail Varnish

There will be other options but thats what we used to use to stop transformer buzzing
Just paint it onto the coils

I think i will just disconnect it rather than mess around with it (along with the socket, i mean the whole part of the mirror) and just be done with it. I wet shave and charge my toothbrush in the bedroom anyway