Conveyor dryer...what does everyone know about electricity?

[Ripcord]

I've had my dryer for ten years (240 volt BBC Little Buddy) and it's always performed the same day after day, month after month. But today I heard a loud "pop" and smelled the familiar ozoney scent of a short circuit...So I figured something needs to be replaced. But I sent a few test shirts through it and monitored the exit temps with my laser thermometer, and there doesn't appear to be anything out of the ordinary. What might have caused the short circuit, and should I be concerned about needing to replace panels, etc.? This is my huge busy time of year, and if I need to take care of something I want to do it right away.

[Frog]

I'm guessing a momentary short from a a wire which has lost some insulation and moved slightly for one reason or another. I'd check the wires at the temp control and/or the wires going to the panel.
You should see a scorch mark somewhere.

[Itsa Little CrOoked]

I don't know a single thing about your drier or its circuitry. Andy may have nailed it.

But a largish capacitor that blows can make a "pop" and the drier might still work. A welder often will.... I blew a 600 Micro Farad cap on a Lincoln Mig Welder and never did replace it. I worked fine, but there were 7 others--all designed to smooth the arc, if I'm not mistaken. I don't know if your outfit even has capacitors of any size, so I probably shouldn't even say anything.

To verify if you have heat on each panel, turn off the lights and see if they are glowing during initial heatup.

Since its' after hours now, I'd open the panel and see if there is a blown cap. Then tomorrow you could call your guys.

<<<<SHUT THE BREAKERS OFF FIRST>>>>

[Frog]

Little Buddies are really basic dryers. http://bbcind.com/wp-content/uploads/2014/10/LB_Manual.pdf
I don't now if Rip's has a heat control as they are an option on that dryer.
I assume that they use one of those infinite controls like on electric ranges. They fry as well.

[ScreenFoo]

I know that if you have caps without bleed resistors in a piece of gear like that, it's perfectly capable of killing you with no power attached. 
You can safely discharge capacitors that don't have bleed resistors with insulated leads and your own resistor bank, but it's not something easily explained over the interwebs.

IMHO if you really don't know what you're looking at or doing, do NOT poke around in there, live or not.
Electricians are cheaper than doctors...
(Oh, and I doubt there ARE caps in there, unless there's a start cap on a motor or such, but still, better safe than sorry)

As far as the heat control goes, most of those are as Frog says, very similar to those on the stove.
Not hard to replace, but carry high current and should be done properly.

[3Deep]

I bet you have a burn wire somewhere that's just waiting to cuz you trouble later on, I've had that happen on our dryer and it kept running fine until it just burn into....best to check it now

darryl

[Frog]

I know that if you have caps without bleed resistors in a piece of gear like that, it's perfectly capable of killing you with no power attached. 
You can safely discharge capacitors that don't have bleed resistors with insulated leads and your own resistor bank, but it's not something easily explained over the interwebs.

IMHO if you really don't know what you're looking at or doing, do NOT poke around in there, live or not.
Electricians are cheaper than doctors...
(Oh, and I doubt there ARE caps in there, unless there's a start cap on a motor or such, but still, better safe than sorry)

As far as the heat control goes, most of those are as Frog says, very similar to those on the stove.
Not hard to replace, but carry high current and should be done properly.

The manual to which I linked includes a wiring diagram. That should answer any questions about what, if any, capacitors this unit has.


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[ebscreen]

DC motor speed control likely has a cap across the incoming voltage to smooth it out. That can blow
and unless you have dirty incoming power you likely won't notice a difference, though the fact that it
went can indicate voltage fluctuations.

I put 40 volts through a 36 volt cap the other day, only 100uF but it was an impressive pop and actually
caught on fire.

[Ripcord]

Thanks for all the replies. I ran the dryer all day long without an incident, so I guess I'll just keep using it. When I get a chance I'll pull the lid off and see if I can find a scorch.

[ScreenFoo]

EB:  I've found that when I try running 36 volts through a 36 volt cap, the same thing often happens.   

I did get a chance to look at those diagrams, Frog, but they do not provide 'schematics' per se.  The wiring on the heat side is very simple, but the speed control for the belt is only listed for input and output voltages--but is unlikely to have anything all that dangerous inside.

I'd bet you will find a burnt looking connection somewhere in there.
A guess would be the pop noise came from a marginal connection in the IR panel circuit that's taking up arc welding in it's spare time...