ECN Forum Forums General Topics of the Trade General Discussion Area Leaking Transformer

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.

Thanks,
Byron

Definitely NOT a good sign.

Is the transformer overloaded? Getting excessively hot?

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.

Thanks

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!!

Expect a call back soon to replace the flamed-out unit. 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!

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.

Byron

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.