Power cords Arc when plugged in

[tallan]

Hello,

Well the unit works fine (CBT-16D) I had it out for testing when I went to unplug it I got a really nice Arc, even turned the plug prong a little black. Everything was off so I can't imagine the little red light is drawing that much power.

I pluged it back in and noticed a little arc and the same when unplugged so it is acting like their is a nice power draw from something. It's on a GFI circut which has not tripped and I did test it as well.

Any Idea's? Perhaps a Nuetral is grounded some where?

Any advice you can give on what to check would be greatly appreciated!

Thanks,
Ted

[Guest wbottomley]

tallan wrote:

Hello,

Well the unit works fine (CBT-16D) I had it out for testing when I went to unplug it I got a really nice Arc, even turned the plug prong a little black. Everything was off so I can't imagine the little red light is drawing that much power.

I pluged it back in and noticed a little arc and the same when unplugged so it is acting like their is a nice power draw from something. It's on a GFI circut which has not tripped and I did test it as well.

Any Idea's? Perhaps a Nuetral is grounded some where?

Any advice you can give on what to check would be greatly appreciated!

Thanks,
Ted

If the neutral was grounded, the GFCI would trip. The power supply does draw some current but how much, I don't know. Haven't had that kind of a problem before.

Nice to see another North Carolinian doing animation.

[kevin]

Double check all you connections on you controller to snug them up.

*** Double check you connections on your controller for loose strands of wire that might be touching other connections. this is the most common with the screw in terminals.

Make sure your ground wires (if using 3 prong cords) are not touching any other wires or wrapped around a power/common wire to excess.


Since everything was off this would tell me that you have a issue with your power cords. It could even be that it is not your controller but the plug that the controller is bing plugged into.

Double check your Polarity on your power cord and on the outlet.

[-klb-]

Do you have your lights plugged into the controller? There may be a brief period during controller start up where the output state is undefined...

- Kevin

[tallan]

Hey Guys, Thanks for the quick responces. Hello MountainWXman, Someday I may take a drive by your display, from what I have seen it looks very nice.

Kevin, I got to thinking about what you said with the grounding terminals. I did recently mount the card in a weather resistant box that is plastic so I tucked all those ground terminals underneath the card. I did not connect them all together and perhaps that maybe the reason the ground fault is not tripping.

So do you think I should gather them up and connect them all even though it's a plastic box? I bet one of them is touching something on the board which is causing the current draw and I will check it this eveing and let you all know.

Thanks again,
Ted

[kevin]

even in a plastic box I take all my channel grounds and hook them to the plug in ground.. Just to make sure they don't flop around in the box and end up sticking to something while in storage or moving them.

It works as a floating ground by conecting the channel ground to the power ground.

[tallan]

Hey Kevin,

Yep, I think that maybe the way to go, after thinking about it a bit more I think the board is mounted on a plastic piece kind of sealing off the bottom. I wouldn't doubt one of those working it's way out just enough to touch something. They don't like to stay put thats for sure.

After seing the arc on the plug I'm sure I maybe able to locate the offending grounding terminal. I'm just glad nothing went up in smoke.

Well I usually leave them plugged in but after that I unplugged everything. Yep that will be the first thing I do after work I hope it's easy to find but if not I will tie them together and see if it doesn't start kicking the ground fault.

Stay tuned I'll update what I find.

Thanks again,
Ted

[Shubb]

It could be the plug also, maybe when you plug/unplug it moves just enough in the box to ground something.

[Tim Fischer]

kevin wrote:

even in a plastic box I take all my channel grounds and hook them to the plug in ground.. Just to make sure they don't flop around in the box and end up sticking to something while in storage or moving them.

It works as a floating ground by conecting the channel ground to the power ground.

I've never used grounded cords for the outputs. But on my few boxes where I have them on the input and are in plastic boxes, I just wrap the ground wire around one of the screws on the heat sink. Better to have that grounded than the wire just unused IMHO...

And yeah, you'd definitely want to tie the input grounds to the output grounds if you have them -- otherwise you have what appears to be a 3-wire safety grounded circut, but you really don't. If you plugged in something like an outlet box that required the safety ground, it wouldn't be there for you...

-Tim

[tallan]

Hey everyone,

Here's the update. I can't figure it out. I checked the box and everything looks great, the ground terminals are safely tucked under the card and isolated by the plastic mounting plate. I figured out what I needed to get them all grounded so I will finish that up tonight. Basiclly a self taping screw, i did not have any though.

I did see some post mentioning bad power cables and got to wondering if perhaps my extension cord might be going bad. It did run across the driveway last season unprotected so perhaps the problem could be there. It is a bit beat up so I will check that out too.

Thanks for the all the input, I'll keep you posted once I track this issue down.

Ted

[JimC]

Ted,

Someone also asked this... Do you have any lights plugged into the outputs?

If so, there is a definite chance of the input power connections arcing when you plug them together. During power-up of the processor, the outputs are in an undertermined state. Once the processor gets up and running the outputs will shut down. During the undertermined period you may have all your circuits active even know the computer is telling them ALL-OFF.

You mentioned that this also happened when you unplug the board. I guess if you unplugged it slow enough the processor may start sending out ON commands as the power was dissapating.

Anyhow, unplug all of the outputs (if you had stuff plugged in to them) and see if you still get the arcing. If the arcing goes away then "problem solved". It is a "normal" function of the board. I have black weld marks on my big power cords from the same thing.

You can plug a 100W spot light into the board and see it flicker on/off when you plug the board in. You can also hook an ammeter inline and see if you get a big spike when you plug the board in. It should quickly go back to "zero" once plugged in.

If your board is functioning normally and the GFI isn't tripping and the above hypothesis isn't correct, then it has to be current flowing from the neutral to the hot wire (short of some sort). It would seemingly be doing this 100% of the time while the board is plugged in. This would show up on an ammeter. It would have to be a resistive short as well. If it was a direct short then the connection would have fused open a long time ago.

Hope this helps.

Jim.

[jim st john]

The power input to the LOR card goes directly to the primary of the transformer that powers the electronics, so there is an inductive load across the line at all times. An inductive load will arc when power is disconnected, and possibly when it's connected, especially if the connection between the prongs of the plug and the receptical don't make and break cleanly.

In other words, there may be nothing wrong with the board. If you have more than one controller, it would be interesting to know if the others act the same way.

[tallan]

Hello JimC and jim st john

Oh yes I have all the channels plugged in. 4 100 mini's per channel for my mega tree. I know the amperage is up there and if what you say is true then perhaps that is all that is happening.

I did try the other boards I have (PC16 and another 16D) with nothing plugged in and saw no arc at all. There is also a PC16 hooked up as well but only 4 100 mini's on 8 channels it too arcs but not as bad as the full one.

I wonder if there is a way to measure that somehow? It's got to happen pretty quick because you don't see the lghts come on.

Well they both run great with no issues so perhaps the inductive load is the cause.

I ran another extension cord out as well a brand new one and it arc'ed a little as well. I have found that the dedicated circuts don't seem to arc as much as other circuts that have a little load on them. Perhaps the dedicated can provide all the power more quickly then the one that are loaded a little.

After thinking about it I don't remeber the other 1/2 of the plug ever arcing at all. It only happens on the plug that powers the board. I guess if the board is powered the load is off huh. Of course I always pluged the one powering the board in first.

So what to do with the grounding terminals? Sould I connect them even if in a plastic box? Should I connect them to the heatsink as well to include the board in the ground loop?

Thanks again for everything, I believe it is the inductive load causing the arc.

Ted Allan