stray voltage diy led build

[kpiotrowski]

first off, is it common to to have stray voltage when measured from the aluminum housing of an led build to ground. 52volts!

I have no stray voltage in the display tank below.

 

[kpiotrowski]

top view




bottom

 

[rajkovich207]

No you shouldn't my guess is you have a bit of solder touching the heat sink giving you stray voltage like that. I would look for excess solder or wire touching the metal. Be careful as well you could end up shorting things out

 

[TJ's Reef]

Good question Kevin, I'll have to measure mine as sure there is at least a little stray voltage because can feel it when I touch with wet hands. With my 108 LED's having 216 soldered connections very near the Aluminum framework would not surprise me to register a few wandering volts. Looks like you have a few more than that............

Cheers, Todd

 

[kpiotrowski]

looking forward to those results.

thanks!

 

[kpiotrowski]

No you shouldn't my guess is you have a bit of solder touching the heat sink giving you stray voltage like that. I would look for excess solder or wire touching the metal. Be careful as well you could end up shorting things out

thanks, yes, this is why I havn't simply grounded the fixture or poke at any solderirng yet. was worried about extra strain that may put on the drivers.

 

[Reefing Madness]

52VAC from a DC power source at the housing?? Thats wierd.

 

[kpiotrowski]

I should add, all the drivers are connected to one cord, all cooling fans are are run on seperate transformers ( I didn't build this btw) and everyhting is connect to that power strip you see on the left in top pic. that power strip goes to the apex, which is on a GFCI and has not trip when I have be shocked. shock is very much like a fresh 9v on your tounge. and it will always shock you when on. nothing when off.

 

[kpiotrowski]

52VAC from a DC power source at the housing?? Thats wierd.

ok, so that may tell me something! I didn't build ( although I could) but i havn't researched the drivers that much. so they are dc current?

in that case I would wonder if its soley the power strip supplying the stray voltage?

what say you?

 

[SeaClown]

I am an electrician and my guess is that you have a direct short to the aluminum frame of your fixture. You could always try using a different power strip to see if that's it, but I think you have some over solder on a connection somewhere. The reason for drivers on LED lights is that they don't run on 120v AC. They are all DC and the voltage of 52 that your getting sounds about right for where they would run. Which is the reason for thinking you have a direct short. Another possibility is a defective driver or fan that has a short in it. If you have a decent DMM I would start testing components first to make sure they are all the same as each other, it may narrow your search down. Good luck.

 

[kpiotrowski]

ok, unplugged led drivers and plugged them in to extension cord, 53volts. fixture with just the 12 cooling fans on 6 transformers, 2v.

so help me understand here. I don't know the technical terms but if there was a short. a direct connect of ground on any soldier on any led, would the driver for that led short out and simply not work?

 

[kpiotrowski]

also, each driver has a fuse and resistor inline. don't know their values.

 

[SeaClown]

A direct connection of solder to frame will cause voltage through the frame of your fixture. It may cause that driver to not function properly or it may cause that driver to short out and never function properly again, that kind of depends on the quality of the driver. 2 volts seeems low, depending on the fans you have I would think computer fans probably and would run at 12 volts +/- 1.

 

[kpiotrowski]

A direct connection of solder to frame will cause voltage through the frame of your fixture. It may cause that driver to not function properly or it may cause that driver to short out and never function properly again, that kind of depends on the quality of the driver. 2 volts seeems low, depending on the fans you have I would think computer fans probably and would run at 12 volts +/- 1.

my limited knowledge on this subject has me believing that if there was a direct connection of postive to ground that surely it would pop a fuse or blow the driver. wish I understood more!

 

[SeaClown]

a resistor in line just adds resistance. it drops the voltage to each driver but still uses the full amount of power pulled from your receptactle (the wall plug). Unless your drivers specifically say they need only a certain amount of voltage input I'm not sure why they would be in the line. We only use in line resistors for fire alarm systems at work. As far as the values of the resistors, the colors on them and the order the colors are in indicate the value of the resistor.
Fuses are a great idea.

 

[SeaClown]

It should pop a fuse

 

[SeaClown]

unless your fuse is not properly sized. Meaning if you have a 2amp fuse and your light only pulls .5amp and shorting it cause a another 1.5amp draw then you only have 2 amps flowing through the fuse and it wont pop.

 

[kpiotrowski]

unless your fuse is not properly sized. Meaning if you have a 2amp fuse and your light only pulls .5amp and shorting it cause a another 1.5amp draw then you only have 2 amps flowing through the fuse and it wont pop.

wouldn't the driver blow then?

 

[SeaClown]

More than likely but not guaranteed. If the short is before the fuse then it wouldn't necessarily blow either as it is dumping excess voltage and amperage before it gets to the fuse, may be a good place to start looking for the problem. Not sure how everything is wired in your system, but if there is solder before the fuse I would check there first. At work we don't troubleshoot light fixtures much. Something like this we would send back to the manufacturer and get a new one. A T5 fixture would either be wired wrong or a bad ballast, easy fix. The LED fixtures have a lot more going on and that makes them more difficult to troubleshoot, especially a DIY job. Also the resistor could be dropping enough of the problem voltage that causes the fuse to not blow. You mentioned that you didn't build it, maybe you could get the person that did build it to fix it.

 

[kpiotrowski]

A little bump here. anyone else care to test for this also?

thanks!