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#57236 - 10/07/05 08:33 PM Leaking Transformer  
bwise121  Offline
Joined: Sep 2003
Posts: 114
Sacramento, CA USA
Recently I installed a 120V to 12V 300 Watt transformer for a tech lighting system at a residence. In less than 24 hours the owner noticed that the transformer was leaking brown "goo". Is the transformer going bad? Is this normal? Any insight would be appreciated.


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#57237 - 10/07/05 08:35 PM Re: Leaking Transformer  
NJwirenut  Offline
Joined: Sep 2001
Posts: 806
Bergen County, NJ
Definitely NOT a good sign.

Is the transformer overloaded? Getting excessively hot?

#57238 - 10/07/05 08:53 PM Re: Leaking Transformer  
bwise121  Offline
Joined: Sep 2003
Posts: 114
Sacramento, CA USA
Not that hot. The lighting designer has 5 50 Watt MR-16 bulbs on it even though the transformer is for 300 Watts. There is an extra wire (I guess has extra windings) that gives a 10% boost. The designer suggested that I use this wire instead of connecting the hot to the usual primary black one.


#57239 - 10/07/05 09:49 PM Re: Leaking Transformer  
LearJet9  Offline
Joined: Apr 2005
Posts: 197
Millis, MA USA
That is absolutely not normal. Unless of course the instructions tell you leaking brown goop is just part of the normal operation of the unit!!

#57240 - 10/08/05 02:43 PM Re: Leaking Transformer  
mxslick  Offline
Joined: Oct 2004
Posts: 803
Atomic City, ID USA
Expect a call back soon to replace the flamed-out unit. [Linked Image] If you're really lucky it won't catch anything else on fire too.

And when you replace it, ignore the designer (are they qualified EC/engineer or just interior designer) and connect the primary without the 10% boost.

Was the unused wire capped off?

It is possible on an encapsulated transformer to have windings burn out (and melt the compound) without excessive heat rise on the case.

Let us know what happens!

Stupid should be painful.

#57241 - 10/08/05 08:42 PM Re: Leaking Transformer  
bwise121  Offline
Joined: Sep 2003
Posts: 114
Sacramento, CA USA
Just got the call back! The transformer was supplied by the owner from the lighting store. I told him I'd replace it for free being the nice guy I am.

I'll take your advice on not using the boost winding mxslick, and yes the other wire was capped off.

Thanks all for your responses.


#57242 - 10/11/05 12:31 AM Re: Leaking Transformer  
mhulbert  Offline
Joined: Oct 2004
Posts: 132
Anaheim, CA USA
The "boost" wire is typically used only on dimmed systems. There is an inherrent loss through dimmers, even at 100%, the lights aren't getting the same amount of power as they would on a switch. Usually the boost is only about 3-5%, so your 10% boost sounds more like it is for long secondary wire runs.

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