Electric motor question
#9
Working on restoring a Sioux bench grinder (10", 1725 rpm --big ol' machine!)  Took off six coats of paint to get to the base metal [Image: yellowrolleyes.gif] 

Now I'm trying to undo some jackleg electrical work.

Big problem is there's a resistor in the circuit -- hollow ceramic core wound with fine wire -- that's seen better days.  It measures ~10 ohms.

What kind of resistor do I need to replace it?  Anyone know a good source? [Image: yellowconfused.gif]

I haven't drawn up the circuit yet to see what wires go where -- there's some extras -- but what does the resistor do?  Any idea where it goes?  (wires are busted).  There's a single capacitor in there.

Ran before I started putzing with it, I tried to mark everything but we all know how that works
Crazy
"Truth is a highway leading to freedom"  --Kris Kristofferson

Wild Turkey
We may see the writing on the wall, but all we do is criticize the handwriting.
(joined 10/1999)
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#10
(02-23-2017, 04:36 PM)Wild Turkey Wrote: I haven't drawn up the circuit yet to see what wires go where -- there's some extras -- but what does the resistor do?  Any idea where it goes?  (wires are busted).  There's a single capacitor in there.

It's probably in series with the capacitor, powering either a start winding, or a start/run winding.
Tom

“This place smells like that odd combination of flop sweat, hopelessness, aaaand feet"
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#11
Link to the basement discussion..
https://forums.woodnet.net/showthread.ph...pid7437546

It's purpose is to dissipate power but without a circuit description it's unknown what it's purpose is to your machine.
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#12
I'll try to get the circuit sketched out.  There's some extra wires and so forth so it isn't gonna be easy.
"Truth is a highway leading to freedom"  --Kris Kristofferson

Wild Turkey
We may see the writing on the wall, but all we do is criticize the handwriting.
(joined 10/1999)
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#13
How big (in physical size) is the resistor ?   Have seen resisters in parallel with the capacitor to dissipate charge.   Can be in series with the capacitor to change the phase angle to less than 90 degrees.     I have not seen one in a motor to change the phase angle.    Roly
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#14
(02-23-2017, 07:28 PM)Roly Wrote: Can be in series with the capacitor to change the phase angle to less than 90 degrees.     I have not seen one in a motor to change the phase angle.

Neither have I, but that's what I'm thinking.  And if it's switched in and out for starting vs running with the capacitor remaining in the circuit (changing the phase angle), it would make some sense.

OP: What's the hp rating of the motor?
Tom

“This place smells like that odd combination of flop sweat, hopelessness, aaaand feet"
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#15
Per the other discussion its 10 amps at 120 v.  If it was a Craftsman that would be 22 hp.  Everyone else might round it off to 1ish.
Blackhat

Bad experiences come from poor decisions. So do good stories. 


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#16
[Image: grinder%20wireing%20diagram.jpg]

Best I can figure out.  As soon as the new resistor gets here I'm taking it to the motor shop for rewiring.

I figure it's as old as I am so new wires are a good idea (especially after looking at the old ones!!!)

link to other thread
"Truth is a highway leading to freedom"  --Kris Kristofferson

Wild Turkey
We may see the writing on the wall, but all we do is criticize the handwriting.
(joined 10/1999)
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