LV track lighting problem

[ItsHot]

I have problems with a 12 volt track fixture. This fixture is the "S" curve type, with 3 pendants an 2 spot heads.( 5 -50w=250w) Customer was told from shop where he purchased fixtures from while he was building home, that the transformer was more than likely bad.Since he was having problems. Homeowner purchases new transformer and calls on me. I get on-site to troubleshoot the fixture. Finally locate the transformer at a can-light in ceiling. Check voltage going into transformer..110.8 volts. The lights are not burning. Kill power,change out to new transformer. Lights come up for about 10 seconds and then go off.???? Check output voltage of "new" transformer with no low voltage at taps???Nothing? Go to dimmable switch location. There is one 1000w dimmer serving 3 switches. Load side of switch reads 120 volts...everthing else appears fine. I then "jump" out the transformers from a countertop receptacle to bypass switch to see what happens??? Nothing! After alternating the 2 transformers, and checking voltage I finally get the fixture to burn using the old/original transfomer. I let the fixture burn for about 10 miutes, while cycling the dimmer slide. Everything seems fine. This is with the circuit back on the switch at this point. I began to button everything back up only to have the fixture to lose power to lamps again!I then triple check my connections.. they look good. I have a transfomer problem! The 2 transformers are identical.. LightTech brand, 120volt to12 volt, 300watt with thermal overload protection.I believe the fixture is also LightTech. Can't buy new stuff that works anymore!!Lamps are known to be good/ok, and are the correct 12 v /50w lamps for this application. Any comments or help is greatly appreciated! Thanks!!:smile:

 

[Dennis Alwon]

I had trouble following but if there is a dimmer in the picture then take it out and see if the system works. If it is an electronic trany then the dimmer must be of the electronic style also.

 

[ItsHot]

Sorry for the long thread Dennis! I used the drop cord at a receptacle to bypass switch for testing purpose.The lamps worked. I then made everything back up to the switch. Everything worked on switch for about 10 minutes. Then lamps went back off???? The replacement(new) transformer is identical?brand?specs as the old one, that worked on fixture for about 5 years. I think I got hold of a bad(new) transformer? Because all I got was about 10 second burn out of the new transformer!:-?

 

[Dennis Alwon]

Did you try to bypass the switches a second time-- in other words when you made the switches back up and it worked for a few minutes, then went out-- after that did you bypass the switch again.

Was this switch a dimmer switch--- I don't understand one dimmer feeding 3 switches.

 

[hurk27]

Many transformers can't be dimmed, and if they can be dimmed you have to use a special dimmer for LV magnetic transformers.

I have had to fix this mistake a few times and it is because the transformer will over heat with a standard dimmer, this will cause the thermo-overload to trip and reset when it cools, the new transformer might have a thermo-fuse in the winding as most of the new ones do.

hope this helps

 

[quogueelectric]

Many transformers can't be dimmed, and if they can be dimmed you have to use a special dimmer for LV magnetic transformers.

I have had to fix this mistake a few times and it is because the transformer will over heat with a standard dimmer, this will cause the thermo-overload to trip and reset when it cools, the new transformer might have a thermo-fuse in the winding as most of the new ones do.

hope this helps

I have a deep hatred for those track hung on aircraft wire systems. I always get stuck installing them and usually missing parts. Lasers are esential for these installs. I do think that yr problem is mismatched dimmers to xformers.

 

[hurk27]

I have a deep hatred for those track hung on aircraft wire systems. I always get stuck installing them and usually missing parts. Lasers are esential for these installs. I do think that yr problem is mismatched dimmers to xformers.

While I hate those types too all the balancing weights and trying to get the spots to point in the right direction, but I think the OP was about those bendable tracks the ones that come straight but since the box shows them in an "S" curve the home owner wants them as the box shows they are a pain to bend smoothly without getting flat spots

 

[guitarsarge]

Many transformers can't be dimmed, and if they can be dimmed you have to use a special dimmer for LV magnetic transformers.

I have had to fix this mistake a few times and it is because the transformer will over heat with a standard dimmer, this will cause the thermo-overload to trip and reset when it cools, the new transformer might have a thermo-fuse in the winding as most of the new ones do.

hope this helps

I agree. If you leave the switch bypassed for 10 mins or so and the lamps stay on, and then after cooling, back through the dimmer and they turn off after 10 mins, then I heavily suspect the switch.

As for bending the serpentine, I've used 3/4" plywood to cut the curves and placed it on a flat surface (3/4" plywood) put a block of wood or dowel,peg or rod at one end. Then you can carefully bend a nice curve. Works well when you need two or more that are identical to offset each other etc...

 

[ItsHot]

thanks!

thanks!

The new transformer is identical to the one that was the original install. So I guess it is "dimmable". It worked on the fixture for close to 5 years. I was thinking that I had got ahold of a "bad" new transformer:-? I did not have a dimmer switch onboard to try the replacement. The switch location is at a 3g box with 2 other dimmer switches! Talk about a full box! Blue plastic with all the screw holes stripped! This box has had some traffic. Will need lagscrews to hold the devices in place!:grin: There can be a lot of "trouble" in troubleshooting! Thanks for your help!