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Capacitor problem

NaturesColor

Feb 19, 2018
1
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Feb 19, 2018
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The capacitor on my woodturning lathe melted. Seriously bad smell. Although I'm ignorant of these things I figured out it was the running capacitor. Picture attached. This was replaced with a 21-25 uF x 220 / 250 VAC. This however, also failed. It started to work, ran fine for a few minutes, then tripped the circuit. It ran again after reset, lathe sounded rough but again tripped the power and had some oil leakage.

So now I'm back to square one with no idea what to do next. Any advice much appreciated.Capacitor.jpg 20180211_115059.jpg 20180211_204627.jpg
 

Kabelsalat

Jul 5, 2011
182
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Jul 5, 2011
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182
If there was a full shortage in the cap, the motor may have take som damage too before fuse tripped.
 

73's de Edd

Aug 21, 2015
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Sir NaturesColor . . . . .

Ahhhhh So . . . . most honnable motor . . . . come from and made by Ke Ting Industries in Tai-wan-on.

Are there TWO separate capacitors . . . . . one being under each metal housing . . . like the one you are touching?
With the other one possibly also being bad ?

Does the motor just HUMMM on power up ?.

My random . . . . . single phase motor situation(s) . . . .

On my mere 3/4 HP / 3450 RPM's unit, there is being a starter winding involved that is wired thru a centrifugal switch.
On power up, that winding is being in circuit and gives a fierce magnetic surge to get the motor rotor initially moving.
After that initial rotor spin , the centrifugal switch has detected motor rotation and opens to disengage the start winding.
Now with time, what happens to my unit is that that ultra super microfine talcum powder like sawdust ,just as is seen on YOURS gets inside and between the cent sw contacts and I have no startup winding being initially switched in circuit.
So the regular run windings now have a dormant rotor sitting there, with the run winding pulling one hefty current . . if the rotor is not turning, and since they didn't have the magnetic starter windings initial OOOOOOmph to get the rotor started initially at power on. . . . . .The unit HUMMMMS for only a while and then trips the breaker.
I can either disassemble and clean the centrifugal switch contacts of the slight sawdust particles, or BLOW it out with an air hose.
OR, without having to move all and set up to do that, I usually pop off the belt from the motor pulley and have the pulley then being open to receive a venetian blind cords length of wrap around .
That then gets wrapped around the pulley in the CORRECT direction so that with a fast and smart pull on the cord . . . a . . la . . .lawnmower engine style . . . . then gets the rotor spinning and a flipping on of the the power switch has the unit running normally.
And . . . HEY . . . 9 out of 10 times that movement dislodges the film of sawdust. Then it starts normally the next turn on.

73's de Edd
.....
 
Last edited:

hevans1944

Hop - AC8NS
Jun 21, 2012
4,878
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Jun 21, 2012
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Why did you replace the original, burned up capacitor, that was rated 25 μFd (+10% -0%) at 250 V AC 50/60 Hz with a much larger capacitance of 200 μFd and much lower 125 V AC rating?

I would also suspect, and test for, a centrifugal switch that isn't operating properly. Something caused the original capacitor to fail in a spectacular manner. It would be wise to find out why before installing any more capacitors. And I would follow the ratings of the original capacitor as closely as possible. Higher voltage rating is okay, but higher capacitance rating is not.

Maybe Travis could chime in here. He knows just about everything there is to know about motors.
 
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