WatchCraft 1/10HP Lathe Motor Assistance

[RyMoeller]

Hello all,

I was cutting brass bushing on my Peerless lathe this weekend when I began to feel an unpleasant sensation in my arm- a bit like a high frequency vibration but somehow not quite.  Well, having been on the wrong end of a few electrical escapades I knew my brain was confused by what turned out to be a continuous electrical shock.  I pulled out my multi-meter and confirmed that the lathe bed was receiving 3-5 volts back while the motor ran.

The lathe is powered by a very nice Watch Craft 1/10 HP AC/DC motor which has operated without fail until now.  It is long in the tooth though, I would guess it was manufactured in the 50's or 60's.  The internet advises that when an AC/DC motor is shorted it's time to discard it.  I pulled the motor from the lathe and found that one of leads will register continuity when tested against the motor casing and that leads me to believe there's a short somewhere between the field coil and the case- although if it was that simple I'd probably be reading a lot more than 3-5 volts from the bed... anyhow, I can't figure out how to remove the field coil from of the case- there doesn't seem to be any visible screws to hold it in place. So this leads to my inquiry- has anyone removed a field coil from one of these motors before?

And then of course my second inquiry- any experience swapping a lathe motor out with a modern replacement?  I'm thinking one of the 1/15 HP Dayton motors would work well but if anyone has previous experience and would like to offer a suggestion I'm all ears.

 

 

[jdm]

54 minutes ago, RyMoeller said:

I can't figure out how to remove the field coil from of the case- there doesn't seem to be any visible screws to hold it in place. So this leads to my inquiry- has anyone removed a field coil from one of these motors before?

Picture? That help both those that have seen one before, as well the ones that didn't, in helping you.

[RyMoeller]

32 minutes ago, jdm said:

Picture? That help both those that have seen one before, as well the ones that didn't, in helping you.

Yes, I'll provide one as soon as I return home from work. 

[vinn3]

   just install a 1/10 hp. a c motor wired for UK voltage and curent --- 60 cycle  --- I  believe.  vin  --  ps,  if 10  hp. cut well, get a 10 hp.  is the original motor  part of the head casting?

[RyMoeller]

Here's some pics of the disassembly (thus far):

My thinking is that the two posts (left and right in the last picture) run through the iron core and are threaded into the other side of the casing.  It's just a guess though.

Yes @vinn3, I"m leaning towards a new motor for a replacement. The only issue will be getting it mounted securely to the lathe table. I never could decide if I was a machinist or a carpenter so my I'm always scrambling for the right tools for the job!

[RyMoeller]

Looks like progress.  I've got the field coil out and found the wire which I thought was shorted was in fact frayed and touching the inside of the case.

[RyMoeller]

It's fixed.  A little bit of solder and heat shrink and I'm back in business.  Thank goodness because I don't have the money to spend on tools or watches right now. 

[measuretwice]

nice job!

I just took apart a GE DC motor, one the  expensive compound ones and the insulation going to the field coil was just falling off in my hand.  Really disappointing, ended up scrapping it.  Glad to see yours was fixable

[RyMoeller]

12 hours ago, measuretwice said:

nice job!

I just took apart a GE DC motor, one the  expensive compound ones and the insulation going to the field coil was just falling off in my hand.  Really disappointing, ended up scrapping it.  Glad to see yours was fixable

Yeah I was pleasantly surprised.  Just one frayed wire and the insulation was in good shape.  I did consider doing a complete rewiring though but everything was holding up so well I figured best to leave it be.  You can see a lot of oil has been slung around in there over the years though.  Oh and it smelled wonderful- 1960's machine shop.  Yum.

[praezis]

Don't forget to connect the motor case to the grounding conductor!!!

Frank

[RyMoeller]

Oh yes, I did this.  As you can see from the images- it wasn't grounded when I started!  I'm glad I only got a mild shock instead of the 115V and 10 amps I could have received!

[vinn3]

On ‎9‎/‎6‎/‎2019 at 1:00 PM, RyMoeller said:

Looks like progress.  I've got the field coil out and found the wire which I thought was shorted was in fact frayed and touching the inside of the case.

   since you found a bare wire;  it's worth putting back to gether.  in the base is that a "device" for D C power?    can that be discnected for the trial run.?   i like gears and wood work.   i hate electronics.   vin  

[RyMoeller]

17 hours ago, vinn3 said:

since you found a bare wire;  it's worth putting back to gether.  in the base is that a "device" for D C power?    can that be discnected for the trial run.?   i like gears and wood work.   i hate electronics.   vin  

Well I could have just called it an alternating current motor because it's not really run on direct current; I should have called it an electric motor.  AC motor isn't really a great name because that's usually referring to motors used for air conditioning.  AC/DC motor is simply incorrect in this case so I apologize for the confusion. 

The bit that you can see inside the casing is the backside of the reversing switch (and the tubes for the brushes). 

[cjercjer]

Hi, hope you are doing well. I have the same motor and am trying to repare a wire inside the case but can find no way to do this. Can you tell me how you got the rotor out of the case?

Thanks, Jerry

[HectorLooi]

It looks like there are 2 screws holding the end cover to the body of the motor.

Remove them and slip a knife into the gap between the cover and the body. Slowly work your way around the motor. Sometimes tapping the cover with a wooden mallet will loosen up the dirt and corrosion. Spraying WD40 into the gap might help too.

Good luck, Jerry.

[cjercjer]

Think I asked the wrong question. I did open the case by removing the two screws and pulled the rotor out. What I was trying to learn was how to pull the rest of the stuff (field coils?) out of the motor housing. Any ideas about that?

Thanks, Jerry

[HectorLooi]

You mean the stator. I've not worked on this motor but for similar motors, I'll screw a bar across the brass standoffs and use a combination of levering and hammering to coax it out of the casing.

[HectorLooi]

I took a closer look at the photos. The 2 brass standoffs may actually be holding the stator in the motor housing. Try screwing out the brass standoffs and see if the loosens up the stator.

[cjercjer]

Thank you so much for your help. I will certainly try this.

Thanks, Jerry