Low Voltage Track trasnformer failures
I am doing some fix up work on a house for sale including replacing burnt out lamps.
The house has a number of Juno tracks with 12 volt transfers in the head and they operate 50watt MR-16 bulbs.
Made a survey and 2 out out on two different tracks. I had other work to do until I got to these.
Replaced the first bulb and on problem.
Went to work on the 2nd track and found that the bulb was good. Turns out that the transformer had failed. But another light on the same track would now only work for a few minutes and then cycle off. Tried replacing it with anouther bulb thinking that it might have had the wrong size and was over heating. With the new bulb it cycles on and off in a few seconds.
Then one of the other tracks lost a light and 3rd one has a similar flaky transformer.
Opened them up and found that they have electronic transformers. Found some replacements that I could put in for about $20 and I would do that if it where my house and I could monitor them. But since it isn’t I will just replace the whole Juno unit which I am guessing is about $50-60.
Does anyone have any suggestion for the large number of failures and specially 3 in about a 2 weeks period. But a the flaky ones might have had this problem earlier, just did not see it.
Line voltages are right at 120 volts. And in the area don’t expect any power surges and no heavy lighting in the 2 week period.
The house was built in 1980, but on at least some fixture there appears to be an 95 date code so there might have been some remodeling at that time.
Replies
With an electronic unit it's vaguely possible that poor grounding or hot/neutral swap could cause a problem.
Or they could just be at end of life.
No ground. While the track is grounded (at least if it was wired correctly) the module isn't. Just the two connects to the rail for hot and neutral and reversing them won't have any affect.
"Or they could just be at end of life. "
That is what I am afraid of. I want to get the job finished. I am think that there are about 7 tracks with 4 heads on each one. So far all of that that have fail I have been able to get to with my 8ft ladder and library ladder. But if some of the others fail it will be furniture moving and scoffolding.
And that does not count the one track that was never wired up. The wires come down the suspend rod, but no connector!
Are the tracks controlled by a dimmer? There are special dimmers to feed electronic transformers. The conventional kind may damage the transformers.
Good point, though the dimmer is more apt to be damaged than the xformer.
Low voltage lighting transformers have thermal overload protection which if malfunctioning will either shut the transformer down or leave it unprotected.
Do the transformers have adequate ventilation.
A warning though, I personally have experienced a fire as a result of low voltage transformers where the thermal protection didn't work.
Don't take low voltage for granted.
These are not "standalone" units. They are part of a track light assembly.
There is no separate over temp device. The "transformer" (actually an electronic switching power supply) is in a potted module.
I think that they are current limited by design.
When I see similar situations here in Florida I think power surge. We get a lot of lightning. The high variable loads and long rural lines don't help either. In my experience it only takes a good spike or two to kill unprotected electronics.
Supposedly the average house in the US get something like three or four minor spikes a day, I forget the actual figure, and major spikes a couple of times a year. More here in sunny, and stormy, Florida.
Any more I push for people to put a whole-house surge arrestor, about $22, in every main panel. Good quality surge strips, demoted to less critical equipment every year or two, complete the picture to protect audio-visual equipment and another for any computers. I understand that the more of these units you have the better protected the entire system is. I have five in my house. Seven as soon as I replace the ones on my computers and TV.
It is hard to get anything but anecdotal evidence from the relatively few data points, compared to the thousands needed to obtain a valid statistical sample, but I think I see fewer problems where even a basic surge arrestor is installed.
On the other hand transformers sometimes go south for no apparent reason. Even more common if they are no-name imports.
"Any more I push for people to put a whole-house surge arrestor, about $22, in every main panel. "
What kind for $22. It has been a long time since I looked, but if I remember one of the cheapest was the Internatic and they ran about $75.
I agree with you in general about the problems of surges. But I don't think that this is what is happening here.
This is large development with all utilities underground and feed with good feeders and probably multiple feed points. Not a place that will see much in the way power company generated surges.
And in the last couple of weeks, when 2 or 3 more failed there have not been any heavy storms.
Intermatic and other manufacturers make several models. You can get a 'whole-house' model that comes with its own weather resistant case, a steel box with an offset nipple, and a couple of LEDs to monitor it. This runs, last I checked, about $45, my cost retail. While this is more elaborate and the LEDs comforting I have been told that these units are really no better than the simple three wire plastic blocks that can be placed in the panel or on the exterior of the panel through a knockout. About $20 my cost retail.
They are also a potential profit center in that they can get a standard markup and installation is quick. Minimum service call, about $70, for fifteen minutes work if you spend time to explain how they work. Preprint a sheet explaining the situation and you can hand it to the HO on the way out saving seven of those minutes.
These whole house units are not as sensitive as the strips used to protect computers but I think they make a difference. On the other hand they handle larger spikes for a long time and serve to knock the head off surges allowing the more delicate surge strips to last longer.
These units IMHO are valuable and essentially cheap insurance. Had one guy go through motherboards and power supplies every few months, high end units. Once we installed a whole-house unit and a good surge strip he stopped having problems. Called back after a week saying both his computers were stabile for the first time. A problem he had thought was a software issue. Of course he was next to the industrial park and two welding shops. These spikes you could see in the lights and on even a simple voltmeter.
I'm not sure how bad surges are around your area. Even motors, especially if defective can throw spikes large enough to destroy some electronics. Most surges are a couple of milliseconds in duration and don't even cause the lights to flicker.
I suspect that the track heads may have suffered from the headlight syndrome. Story goes that a guy pulls into a garage and demands that the mechanic go over his electrical system because he is sure something is very wrong because both headlight went out at the same time. Actually only one headlight went out that day. The other one had been burned out for months but he had failed to notice.
The cheap heads have been going out one by one for some time but no one noticed. What killed them I don't know. The contacts on cheap units can distort after a couple of times being remounted. I have seen the tabs supposed to make contact push in and fail to snap back out so they could make contact the first time they were installed.
Another thought is that these units usually have a fuse and/or a thermal overload protecting the transformer. If the wrong lamp is used it can overload the transformer and overload and/or overheat the coils. Potted fuses are a total loss and thermal overloads can wear out if made to cycle enough. Then again these heads may have been dockside cheap or defective from jump street.