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Rewinding 230V 1-Phase and Choosing Capacitors

Rewinding 230V 1-Phase and Choosing Capacitors

Rewinding 230V 1-Phase and Choosing Capacitors

(OP)
If this is not the right forum for this, please direct me to the right one.

I bought a second hand JET mill with a 230V single phase 2 HP motor.  The start coils burned out shortly after I got it home.  Seems the start capacitor was bad.

I want to rewind it.

From the data plate:
No brand name.  Was on a JET Mill.
Model YN-03-12-06-10-63-01-C800(1)-1-16-3-04-07-7-07
HP   2          RPM   1720
V   115/230     A     30/15
PH   1          POLE  4
HZ   60         EFF   64%
CLASS E         HEAT  60ºC
Serial Number  JD 774546
DATE  1991

Inside a box on the side, there is provision for reversing the motor, but there is no provision or instruction for switching from 115V to 230V and back again.  It seems to be hard wired for 230 only.

There is NO centrifugal switch.  There are supposed to be TWO capacitors, which, I take it are to be "start" and "run".  The bad capacitor all the lettering was gone, so I have no info about it.

You now know everything I know about the motor.

I need to know the proper type of capacitor for both, their mfd rating, and, I am guessing they would be for any voltage in excess of 200.  JET telephone tech support seems to think there is only one capacitor, so I can't trust that.

Only the "start" coils are burned out, so could I get away with replacing just them?

Have read two books on electric motors, but this motor with two capacitors and no centrifugal switch is not covered in either book, neither are there formulae for determining capacitor size in the books.

RE: Rewinding 230V 1-Phase and Choosing Capacitors

Motors with two electrically separate capacitors use a centrifugal switch to take one of the caps out of service once the motor is running. As you are confident that there is no switch I suggest that although you have two physical capacitors they are either paralleled or series connected to suit the high or low voltage winding connections. If you're only after the 230V connection then you could use a single capacitor. A bit of speculation would be that someone mis-connected the caps which then failed because they were not rated for the higher voltage.

Have you had a look on ebay for a replacement motor? UK ebay has motors galore and you can probably pick up a branded motor (e.g. Leeson or Reliance to name couple even I've heard of) than you will pay for a rewind.
  

----------------------------------
  
If we learn from our mistakes I'm getting a great education!
 

RE: Rewinding 230V 1-Phase and Choosing Capacitors

(OP)
Yes, and surpluscenter.com, and surplusmotors.com.  Both are excellent sources of used motors.  I can't find anything under $180.  A local repair shop wants $360, and another $250 to repair this motor.

I am an inveterate tinkerer, who loves to repair just about anything.

Of course, I COULD get really desperate, and pull the START coils, and map them.

Currently, I have a nice Baldor 1 HP doing substitute duty in the mill.  Doing well, too.  The only reason to fix this is in case I wanted to sell the mill, to buy a smaller one.

 

RE: Rewinding 230V 1-Phase and Choosing Capacitors

Those motors often have a dual voltage 115/230 Volt main winding and a 115 Volt start motor. There are both start duty and run duty capacitors. A start capacitor will usually fail if used continuously. If a start winding is meant to be switched it will probably fail if it is not switched.
It sounds as if you are not the first one to play with this motor. I see two reasonable courses.
1> Throw that piece of junk out and get back to work.
2> Rewind the start winding yourself if you can find a mid point connections between two run windings. You may be able to use a starter/capacitor combination meant for a 2 ton refrigeration unit.
Any comments on this options itsmoked?

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Rewinding 230V 1-Phase and Choosing Capacitors

(OP)
Yes, there was a little smoke, and the failed capacitor was hot.  Not all the start coils look burned, and all the run coils look good.

It would be SOOO easy if the motor had a cent switch.

Where's a good place to buy armature wire?  Gotta rewire a DC motor, but THAT, I know how to do.

RE: Rewinding 230V 1-Phase and Choosing Capacitors

A long time ago I rewound a generator, Wouldn't want to relive that experience.  A 2HP single phase motor is a high demand item in the hobby market.  Three phase motors are almost give away items.  If this was my home project I would get a three phase motor and a cheap used VFD on ebay.  That would cost under $100 total. I bought a single phase 120V VFD to 220V 2HP for $65 there.

RE: Rewinding 230V 1-Phase and Choosing Capacitors

(OP)
Changing to a 3-phase from a single phase would demand that I completely rewire the mill.sad  Right now, the power comes into a switchbox, which has thermal overload protection.  It also has a 115V breakout for an auxillary light (unused), and one accessory (also unused). All that would have to go away, and I'd have to kludge something for the 3 phase.  If I would also want power table advance, well ...  

I'll consider it.

I'm leaning toward the idea of a surplus motor.  It would be $$$, but it would be the least hassle.  I'm about $30 into books, already.

Still, if a reader could point me to a website with formulae for these things, it would be nice.

About rewiring the DC motor.  It is from a circular saw.  I have already replaced the saw, so have nothing to lose.


 

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