PITA Low Voltage Lighting......help

Status
Not open for further replies.
M

maddawg-

Member
Hey guys,
I got a irratating problem with some low voltage lighting in my building and was hoping someone here could help me. For starters it is a high line track system from bruck which has a fixture spanning two insulated live wires. The lighting is dimmed on the primary side of the transformer. We had a problem with the lighting inconsistently dimming on its own until it finally went out after a few days. So I replaced the dimmer assuming that was the problem, it wasn't, then I opened up the transformer and the terminals powering the load had been completely fried. So I replaced the transformer assuming the terminals were the problem....well about 10 minutes after installation the lighting began to dim on its own again...I'm about to go and check if the tranny is toast, but does anybody have an idea what could be causing this?

Thanks for any help,

Scott
 
al hildenbrand

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
Re: PITA Low Voltage Lighting......help

Interesting,

I did a High Line installation last Fall, five seperate spans grouped on the Primary side into three switched pools.

One of the connections in a 300 VA transformer secondary failed at the built-in overcurrent breaker. This was a Bruck transformer, so there was a metal flange obscuring the examination of the affected area. . .all I witnessed was the reflected flash from the arcing.

I replaced the transformer, complete, and so far everything is running fine. I chalked up the occurance to statistical bad luck, but after your post, I wonder. . . In my opinion, for the cost of the hardware, that transformer assembly simply shouldn't have failed. I suspect a quality control issue.
 
M

maddawg-

Member
Re: PITA Low Voltage Lighting......help

Its 300W on a 300W tranformer and I'm thinking that may have been the problem. I checked for dead shorts or anything else that might be drawing on it too and found nothing. So I pulled all the lamps and put 2 in and let it sit for a couple hours with no problem so I put 2 more lamps in and I'm waiting to see if it still works. After that I'll put one more in and then finally the last lamp and hopefully that will be when the problem shows up again. I ordered lower wattage lamps and hopefully that will remedy the problem. Maybe it was just a coincidence that last tranny failed and fried the terminals maybe a loose connection.

Thanks,
Kimball
 
iwire

iwire

Moderator
Staff member
Location
Massachusetts
Re: PITA Low Voltage Lighting......help

I opened up the transformer and the terminals powering the load had been completely fried.
Click to expand...
What size conductors are being used?

Is it possible the conductors are overheating contributing to transformer failure.

I think Al's remarks are probably the more likely answer.

Just a question, can you load a 300 watt transformer to 300 watts or should the continuous load be limited to 240 watts?
 
W

wade1

Member
Re: PITA Low Voltage Lighting......help

We had a low voltage installation like that where the dimmer was on the primary side of the transformer. The lights did as you described. After a day of trying everything, we called Lutron. Depending if the transformer is magnetic or electronic, you have to have a special dimmer. Whe got them and it worked great. They were about 5 times as much. I hated eating that for 6 dimmers.
 
G

gregory

Senior Member
Re: PITA Low Voltage Lighting......help

you did not say what the voltage on the transformer secondary is, I will assume it is 12 volts. What size wire are you connecting to this transformer secondary? 300 watts at 12 volts = 25 amps current. Increase this by 1.25 percent for a continuos load and you have 31.25 amps should have # 8 wire connected to transformer secondary. sounds like your wires are undersized. how are you terminating the wires to transformer? are they tight? This sounds like a class 1 insulation, Do you have secondary in conduit?
 
Status
Not open for further replies.
Top