Bandsaw issues
#11
So I decided to do some last minute work in the shop and in the middle of it my bandsaw messed up. I was running it non stop for about 20 minutes. I heard a small pop then a hiss. I look over at it and there is this gray goop oozing out of what I think is a capacitor. I turn the saw off. Turn it on again and it just hums. No moving I can turn by hand so not froze up

Thoughts?


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#12
Run capacitor gave up the ghost is all. No big deal. Let it cool off, go out tomorrow and take the cover off, and disconnect it. Usually on with spade terminals. It should have some info on it to help get a new one or your mfg doc will have the info on what you need. Take the time to clean everything up and clean up the motor too.

Elec Motor shop can help you typically or interwebs will as well.


Glad its my shop I am responsible for - I only have to make me happy.

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#13
(12-25-2017, 12:04 AM)BloomingtonMike Wrote: Run capacitor gave up the ghost is all. No big deal. Let it cool off, go out tomorrow and take the cover off, and disconnect it. Usually on with spade terminals. It should have some info on it to help  get a new one or your mfg doc will have the info on what you need. Take the time to clean everything up and clean up the motor too.

Elec Motor shop can help you typically or interwebs will as well.

Thanks Mike
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#14
If there is only one capacitor, and there are only two conductors from it inside that short cord, then it's a start capacitor.  It would only have blown if the centrifugal start switch was stuck closed, as that type of capacitor is normally not suitable for continuous operation.

Hopefully there are two capacitors, so it's just a run cap that let go.  But being that it won't start, I suspect there's only one (or it's a dual-value, like a lot of HVAC equipment uses), and it blew because it was in the circuit when it shouldn't have been.
Tom

“This place smells like that odd combination of flop sweat, hopelessness, aaaand feet"
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#15
(12-25-2017, 09:02 AM)TDKPE Wrote: If there is only one capacitor, and there are only two conductors from it inside that short cord, then it's a start capacitor.  It would only have blown if the centrifugal start switch was stuck closed, as that type of capacitor is normally not suitable for continuous operation.

Hopefully there are two capacitors, so it's just a run cap that let go.  But being that it won't start, I suspect there's only one (or it's a dual-value, like a lot of HVAC equipment uses), and it blew because it was in the circuit when it shouldn't have been.

I would also think it would be a start capacitor to have that bad of melt down.   Other that the centrifugal switch being stuck were you loading it to the point where the speed slowed enough to get into the start rpm mode ? If after replacing it, it does not come up to full speed within a few seconds shut it down as you will see a instant replay.   Roly
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#16
Naw. I was cutting wine corks. So no slow down
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#17
Replacement capacitor ordered. Laguna tells me its a 80MF 400-450VAC capacitor

Let’s see what happens

Thanks all
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#18
What's worrisome is that it let go while doing light cutting for an extended period of time. I suppose it's possible it was not in the circuit and the heat from the frame caused it to pop. But if the centrifugal switch hadn't opened and it was running with that capacitor in the circuit, it would certainly (eventually) pop the cap, and maybe damage the start winding.

If you're up to it, you could always replace the cap, start the motor, and test voltage across the two cap leads. If it's out of the circuit, it won't show much if any voltage on an AC setting since only one terminal is connected to anything (with the cent. switch open). If it's not opening, it should show some AC voltage across the leads as the cap alternately charges, then discharges and reverses polarity, and so on.
Tom

“This place smells like that odd combination of flop sweat, hopelessness, aaaand feet"
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#19
(12-28-2017, 08:54 AM)TDKPE Wrote: What's worrisome is that it let go while doing light cutting for an extended period of time.  I suppose it's possible it was not in the circuit and the heat from the frame caused it to pop.  But if the centrifugal switch hadn't opened and it was running with that capacitor in the circuit, it would certainly (eventually) pop the cap, and maybe damage the start winding.  

If you're up to it, you could always replace the cap, start the motor, and test voltage across the two cap leads.  If it's out of the circuit, it won't show much if any voltage on an AC setting since only one terminal is connected to anything (with the cent. switch open).  If it's not opening, it should show some AC voltage across the leads as the cap alternately charges, then discharges and reverses polarity, and so on.

Thanks. I’ll check that
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#20
(12-28-2017, 08:54 AM)TDKPE Wrote: What's worrisome is that it let go while doing light cutting for an extended period of time.  I suppose it's possible it was not in the circuit and the heat from the frame caused it to pop.  But if the centrifugal switch hadn't opened and it was running with that capacitor in the circuit, it would certainly (eventually) pop the cap, and maybe damage the start winding.  

If you're up to it, you could always replace the cap, start the motor, and test voltage across the two cap leads.  If it's out of the circuit, it won't show much if any voltage on an AC setting since only one terminal is connected to anything (with the cent. switch open).  If it's not opening, it should show some AC voltage across the leads as the cap alternately charges, then discharges and reverses polarity, and so on.

Some of the European motors don't use a centrifugal switch in the motor, they use a voltage relay potted into the top of the capacitor can to open the start circuit. I've had two fail; one I caught in time, the other destroyed the start winding when it failed in the closed position and overheated the winding.
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