Picked up an old drill press, need a new motor

[2x_Tom]

Picked up an old Shop Master drill press at a swap meet. I stole a pic from the internet because I can't get a picture of it right now. It's a nice little machine. Everything about it just seems solid and well made. It probably has 25lbs on an inexpensive new one.
It has a 1/3hp General Electric motor on it. When I turn it on the motor doesn't have the power to turn the belt regardless of the rpm setting. If I give the belt a little tug to get it started it runs fine. It drills okay but does stop a little easier then I think it should.
I'm thinking the motors just worn out being 40+ years old. What do I look for in a replacement motor? Should it really be another 1/3" hp or would a 1/2 or 3/4 hp of the same rpm be okay? Or will that just turn it into a bit snapping machine? I'm just curious what I can use because I'll look around for a good used Dayton or Baldor motor for it.

 

[G_P]

If the motor uses a starting capacitor the cap could be junk and in need of replacement. If there is a centrifugal switch in the motor it may be gunked up and not working. Both are cheap easy fixed that should be tried before buying a new motor.

 

[2x_Tom]

Thanks. I will check it out tomorrow. Can a capacitor kind of work like that or would it just be a motor does or doesn't run kind of thing?

 

[wild cowboy]

old electric motors are very hard to kill - like G P said, do those two cheap things first, replace the starting capacitor if your motor has one, they are cheap on ebay.

 

[scw1991]

if the motor has a capacitor, then I'd say that is the culprit. Make sure you replace with a capacitor of similar microfarad (uf / MFD) rating.

a 1/3HP rated motor is plenty big for a drill press of this size.

 

[2x_Tom]

Thank you for all the help so far.
Just brought it inside to see what was going on. It doesn't appear to be a capacitor type motor. The cover is off; I'm not familiar with a centrifugal switch (or electric motors in general) but I assume that is what I'm seeing right in the middle of the motor here. Their is a lot of grime and buildup in there that I'm going to clean out and see if it makes any difference.

 

[bisley45]

That motor defiantly has a cap somewhere post some better pics

 

[2x_Tom]

Well it's back together and nothing. Runs like a champ with no load, show it the slightest bit of resistance and it just won't start moving.

Electric motors are not my thing. My compressor motors have capacitors outside of the motor in their own little housing bolted to the motor housing, that's about all I know about capacitors. If this thing has one I have no idea where it could be hiding. Here it is broken down again for some better pictures.

 

[lilredex]

Does it start on its own or do you have to twist the shaft?

Picture four shows the centrifugal switch to engage the start winding, and those contacts need to be clean.

When you power it, it should start running and that switch should disconnect the start winding and it will continue at full speed on the "run" winding. You should hear the start winding disconnect and see a small spark at the switch.

When it comes to a stop, you will hear the centrifugal switch engage again. Those weights behind the switch open up with speed and operate the switch.

Looks like a resistance start motor (no cap.)

 

[G_P]

Thats a non capacitor start motor. Either the contacts on the centrifigual switch are dirty and not working, or the weights on the shaft are bound up and not moving.
Those are the 2 most likely scenarios.

 

[exmaxima1]

Thanks. I will check it out tomorrow. Can a capacitor kind of work like that or would it just be a motor does or doesn't run kind of thing?

That 1/3hp motor is most likely a split-phase start, so you need to check out the centrifugal switch. You can first try blowing out all the dust with compressed air, but if that doesn't work you will need to open up the motor and clean the switch contacts. I use very fine sandpaper, or even crocus cloth if available, to revive the contacts. Don't replace the motor except for last resort.

 

[2x_Tom]

It starts on it's own only if their is no load. Any kind of load and it needs to be spun to start but still has very little power. It's already been blown out pretty thoroughly with compressed air to no avail. I'll try some fine sandpaper tomorrow.

 

[G_P]

That brown ring on the motor shaft with the spring on either side should move up and down. That is the centrifugal part of the switch. If its stuck it will never open the switch in the end cap of the motor and will cause big time start problems.

Also, in this pic, It looks like something hit the arm of the switch contacts hard enough to bend it. Make sure the contacts actually are lining up when they close and that they are not getting jammed up against anything when the motor is put back together.