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Joined: May 2003
Posts: 74
J
jkraft Offline OP
Member
I'm having a problem with these cabinet lights. There's 5 of them with 20 watt MR11+C lamps connected to a 150W/12V electronic transformer, that keeps cycling off and on. The lights are about 20' away from the xfmr fed with 16/4 speaker wire used in parallel.

As a comparison I connected 4 of the 20W lamps directly to a Malibu 200W/12V landscape xfmr. The xfmr gets very hot and the lamps are burning out.

Anyone have experience with this?

Joined: Oct 2002
Posts: 482
Z
Member
Have you tried putting a meter on the xfmr? Try measuring Voltage and Amps on the secondary side, both under load and disconnected from load. This will probably tell you everything you need to know. Also check the line side voltage under both conditions to see if there is any problem there.

Without benefit of these measurements, my first guess is a bad xfmr, unless there is a dimmer on the circuit. They have dimmers made specifically for LV lighting because standard dimmers don't always work properly with transformers, especially electronic transfromers.

Good Luck!

Joined: Dec 2002
Posts: 205
G
Member
I agree, but suggest not a digital meter, or at least use one that measures RMS; You may be dealing with odd waveforms.
Also, I think under no load condition many electronic transformers will shut down and show no output.
(Are you sure they are 20 watt lamps ?)

Joined: May 2003
Posts: 74
J
jkraft Offline OP
Member
Originally Posted by geoff in UK
I agree, but suggest not a digital meter, or at least use one that measures RMS; You may be dealing with odd waveforms.
Also, I think under no load condition many electronic transformers will shut down and show no output.
(Are you sure they are 20 watt lamps ?)


Yep they are 20 watts, and you are correct the electronic transformer shows 0 volts on my digital meter. Should I try my old analog meter?

Joined: Jul 2004
Posts: 9,669
Likes: 6
G
Member
Put one light on the transformer for a load and measure that.


Greg Fretwell

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