# Drill Press Motor Repair Help



## Tutt (May 9, 2014)

I purchased two drill presses at an auction and neither of them have good motors.  I would like to try to repair them, but i don't know jack diddley about motors.  I have looked for a trouble shooting guide online, but i haven't found anything good.  Perhaps y'all can help me out.

Motor 1:
120V 1PH
motor buzzes and will not start even if spun by hand.  motor spins freely when off

Motor 2:
220v 3ph
starts and works, but pulls over 2x the current it should according to my VFD.  It also gets very hot.  Seems to have good torque and work fine other then it getting hot.

Any hope for these?

Josh


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## genec (May 9, 2014)

the centrifugal switch is welded shut.


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## Tutt (May 9, 2014)

Thanks for the reply!  Are you referring to Motor 1?  Is it likely that i can fix the switch or does it need to be replaced?


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## John Hasler (May 9, 2014)

Tutt said:


> I purchased two drill presses at an auction and neither of them have good motors.  I would like to try to repair them, but i don't know jack diddley about motors.  I have looked for a trouble shooting guide online, but i haven't found anything good.  Perhaps y'all can help me out.
> 
> Motor 1:
> 120V 1PH
> motor buzzes and will not start even if spun by hand.  motor spins freely when off



Without knowing what sort of motor it is, I'd guess a bad start capacitor or possibly a bad centrifugal switch.  Try spinning it up with a pull rope.  Capacitors are easily replaced and the switches are often just stuck.



> Motor 2:
> 220v 3ph
> starts and works, but pulls over 2x the current it should according to my VFD.  It also gets very hot.  Seems to have good torque and work fine other then it getting hot.



Internal short, most likely.  Needs to be rewound.

Any hope for these?

Josh[/QUOTE]

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genec said:


> the centrifugal switch is welded shut.



If that were the case the start winding would be energized all the time (unless the start capacitor was also blown).


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## coolvilleshop (May 10, 2014)

Motor one, as the others said, capacitor bad , I really doubt that the motor would have start switch being on a drill press.  Motor two, check that the motor is wired correctly for 240 volt, sounds like it is a dual voltage motor that the leads are wired for 480 volt.


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## videotrack (May 10, 2014)

coolvilleshop said:


> Motor one, as the others said, capacitor bad , I really doubt that the motor would have start switch being on a drill press.  Motor two, check that the motor is wired correctly for 240 volt, sounds like it is a dual voltage motor that the leads are wired for 480 volt.



Re: Single Phase Motor:
If it's a single phase motor, then it's absolutely probable that it will have start winding _and _a run winding, and a centrifugal switch to open the start winding once the motor has started. It may also have a capacitor in the start winding circuit which is used to change phase angle between the two windings and thus provide a higher torque during startup.

There is a relationship between the placement of the start and run windings, and this is what causes the motor to start in the same direction every time.
With power disconnected, I would take the end cover off the motor which usually exposes the centrifugal switch. make sure the insulated sleeve can slide on the shaft, that the spring returns on the counterwights aren't stuck, and that the contacts are clean and open/close freely.

If it has a capacitor, you may be able to make a simple test with a multimeter set on ohms, connect to the capacitor and the displayed resistance value should gradually increase, revers the leads and it should show low resistance which will then gradually increase again. Make sure that your hands aren't touching the leads/probes as this will affect the readings.

testing for shorted tuns is much more difficult, and usually required specialized equipment.

The fact that is buzzes but will not start is a bit puzzling, usually if the start winding is O/C it will start if you give it a bit of direction (e.g. spinning by hand).

Hope this helps


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## Tutt (May 10, 2014)

Thanks for all the help so far!

I took the end cap off motor 1 today and snapped a few pics.

i tried the pull cord trick with no luck.

the centrifugal switch seems to be working also.  It slid free and the weights were free.  The contacts looked pretty clean.  There was a bit of discoloration from arcing, but they were smooth.

i also put an ohm meter on the cap.  Testing it both ways the resistance settled in at about 4 ohms.  It started at about 22 most of the time but seemed to vary every time I did it.

here some pics of it.


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## videotrack (May 11, 2014)

Tutt said:


> Thanks for all the help so far!
> 
> I took the end cap off motor 1 today and snapped a few pics.
> 
> ...



There'sa 5.6K Ohm bleed down resistor across the cap, you would need to have that disconnected, and the leads into the motor disconnected when testing, so the only thing you are measuring is the two capacitor terminals. The 4 ohms measurement you see is likely to be the winding resistance, unless the cap is short circuited (and that's another possibility, except you would not expect to see 22 ohm reading in that case)

Is there a value on the side of the capaqcitor, like 4 mfd or 4 uFD (micro-Farad), if so, do you have access to a meter that measures capacitance?


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## John Hasler (May 11, 2014)

videotrack said:


> There'sa 5.6K Ohm bleed down resistor across the cap, you would need to have that disconnected, and the leads into the motor disconnected when testing, so the only thing you are measuring is the two capacitor terminals. The 4 ohms measurement you see is likely to be the winding resistance, unless the cap is short circuited (and that's another possibility, except you would not expect to see 22 ohm reading in that case)
> 
> Is there a value on the side of the capaqcitor, like 4 mfd or 4 uFD (micro-Farad), if so, do you have access to a meter that measures capacitance?



Just stick a piece of paper between the contacts of the centrifugal switch.  That will open the start circuit.  You should then read an initially low value across the capacitor which should rise to 5.6K.


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## dwdw47 (May 11, 2014)

The single phase motor has a open start winding or the centrifugal switch contacts are dirty and making a connection. The run winding is shorted to its self. Chances are from the motor left on when the start switch or winding failed. Toss it! cheaper to buy a 1/2hp than rewind one.

Three phase motor good chance its wired for the wrong voltage, shorted winding or one parallel windings is backward. The most logical is the motor or not a candidate for VFD, Square wave is hard on many 3 phase motors.
Just a thought without much information this is the many leads to follow. Good luck!
dwdw47


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## Tutt (May 13, 2014)

i was able to bring the capacitor up to work and measure it.  it says 400-440 MFD on the side.  we deduced that actually means 400-440 mFD.  it measures in the nFD range. The terminals are not dead shorted to each other.  So i guess the capacitor is bad?

the wires the hook to the capacitor measure 4 ohms without the capacitor hooked up as you guys predicted.

Is there anything else i can check before I buy a capacitor?  Am i right in thinking that if the capacitor is the only thing wrong, then it probably should have started with the pull cord?


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## John Hasler (May 13, 2014)

Tutt said:


> i was able to bring the capacitor up to work and measure it.  it says 400-440 MFD on the side.  we deduced that actually means 400-440 mFD.  it measures in the nFD range. The terminals are not dead shorted to each other.  So i guess the capacitor is bad?
> 
> the wires the hook to the capacitor measure 4 ohms without the capacitor hooked up as you guys predicted.
> 
> Is there anything else i can check before I buy a capacitor?  Am i right in thinking that if the capacitor is the only thing wrong, then it probably should have started with the pull cord?



The capacitor is bad, but it should start with a rope.


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## videotrack (May 14, 2014)

You can try the capacitor replacement, but as I and others have said, if the start winding is the only problem, then manually turning the shaft should start the motor in whatever direction you spin it.

You cannot rule out a burned out winding, shorted turns etc. 

Presumably you get some magnetic "hum" noise when power is connected, even though the motor doesn't spin? If not, then maybe the run winding is open circuit?

Have you checked that the power cord correctly supplies power all the way to the terminal block on the motor?

Is there any burnt insulation smell that might be an indicator that it has overheated due to shorted turns?

Hope these clues assist.


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## dwdw47 (May 14, 2014)

Before you spend money on the capacitor, take it out of the picture and tie the leads that were on the capacitor together. If the capacitor is bad the motor will start but with a small amount of torque it doesn't need the capacitor to start it only gives it an extra boost.
dwdw47




Tutt said:


> i was able to bring the capacitor up to work and measure it.  it says 400-440 MFD on the side.  we deduced that actually means 400-440 mFD.  it measures in the nFD range. The terminals are not dead shorted to each other.  So i guess the capacitor is bad?
> 
> the wires the hook to the capacitor measure 4 ohms without the capacitor hooked up as you guys predicted.
> 
> Is there anything else i can check before I buy a capacitor?  Am i right in thinking that if the capacitor is the only thing wrong, then it probably should have started with the pull cord?


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## Tutt (May 16, 2014)

Good stuff.  I'll try tieing the wires together and take a closer look for burnt windings tomorrow.  I've learned a lot so far.


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## CluelessNewB (May 17, 2014)

dwdw47 said:


> Before you spend money on the capacitor, take it out of the picture and tie the leads that were on the capacitor together. If the capacitor is bad the motor will start but with a small amount of torque it doesn't need the capacitor to start it only gives it an extra boost.
> dwdw47



The capacitor is not in the circuit to give it "extra boost".   The capacitor is there to change the phase angle between the start and run windings so that starting torque is developed.  No capacitor, no starting torque.  

Those Howell motors are nice running motors and worth fixing if it's only a bad capacitor, dirty starting contacts and/or bearings.   Howell was somehow connected with Kingston-Conley who made motors for Atlas, Walker Turner and others.


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## Tutt (May 17, 2014)

I didn't get as much garage time as I had hoped today.  About all I did was look for signs of a winding getting hot.  One winding is a lot darker than the other.  What do you guys think?


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## videotrack (May 18, 2014)

Tutt said:


> I didn't get as much garage time as I had hoped today.  About all I did was look for signs of a winding getting hot.  One winding is a lot darker than the other.  What do you guys think?



The darker color could just be because of a different insulating varnish on the wire. Is there any burning smell?

Does the motor 'hum' when power is connected?

If you measure resistance across the power plug terminals, do you have a very low reading, e.g. 1 or 2 ohms?


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## Tutt (May 26, 2014)

No burnt smell, but there is only 1.1 ohms between the power terminals.  I measured that without the capacitor hooked up.


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## Tutt (May 26, 2014)

I did some measuring on MOTOR 2, the 3 phase motor.  These seemed more encouraging.

All wires to the chassis were in the Mega ohm range

resistance measurements for delta wiring.
3,5,9 to 1,6,7 - 5.1 ohms
3,5,9 to 2,4,8 - 5.3 ohms
1,6,7 to 2,4,8 - 5.3 ohms

resistance measurements for Y wiring
3,9 to 2,8 - 10.8 ohms
3,9 to 1,7 - 10.5 ohms
2,8 to 1,7 - 10.5 ohms
just for giggles I measures from 4,5,6 to the three legs and they all measured 7 ohms.


i am "pretty sure" I ran it delta when it was pulling too much current.  Should I try it Y?


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## John Hasler (May 26, 2014)

Tutt said:


> I did some measuring on MOTOR 2, the 3 phase motor.  These seemed more encouraging.  All wires to the chassis were in the Mega ohm range  resistance measurements for delta wiring. 3,5,9 to 1,6,7 - 5.1 ohms 3,5,9 to 2,4,8 - 5.3 ohms 1,6,7 to 2,4,8 - 5.3 ohms  resistance measurements for Y wiring 3,9 to 2,8 - 10.8 ohms 3,9 to 1,7 - 10.5 ohms 2,8 to 1,7 - 10.5 ohms just for giggles I measures from 4,5,6 to the three legs and they all measured 7 ohms.   i am "pretty sure" I ran it delta when it was pulling too much current.  Should I try it Y?


  Yes.  Take a look at these drawings: http://www.electricmotorshop.net/home/?option=com_content&view=article&id=683&Itemid=340  Does the motor have a connection table on it anywhere?  Sometimes it's on the inside of the junction box cover.


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## videotrack (May 26, 2014)

Tutt said:


> I did some measuring on MOTOR 2, the 3 phase motor.  These seemed more encouraging.
> 
> All wires to the chassis were in the Mega ohm range
> 
> ...



Usually the motor will show if it is supposed to run Delta or Star, with either a triangle or Y symbol on the faceplate. Some motors are required to have a Star-Delta starter for starting, but 3HP is a little light-on for that being a mandatory requirement. The motor will draw less current and produce less HP in Star, but I would definitely try that.

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Tutt said:


> No burnt smell, but there is only 1.1 ohms between the power terminals.  I measured that without the capacitor hooked up.



The motor should be able to be manually started (e.g. by spinning the shaft with power applied), even if the start winding or capacitor were faulty.

The fact that it won't do this, and that the run windings have continuity, is an indicator of shorted turns. 

A good few people have provided a number of worthwhile ideas for testing, checking, and none of these have lead to a resolution. Unfortunately, I would look at replacing the motor...


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## Tutt (May 26, 2014)

I wired up the motor with the Y scheme and it worked perfectly!  I couldn't get it to pull the rated current no matter how hard I pushed the drill press.  The motor barely got noticeably warm to the touch.

i remember looking for a delta or y on the name plate.  I never could find anything.  Now that I look again the frame is "56y".  Is that the designation or just a coincidence?  I figured that was just for the dimensions of the motor.

i agree that we have thoroughly trouble-shot the single phase motor and it's time to find a replacement.  

Thanks again guys!!!  I learned a lot!


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## videotrack (May 26, 2014)

Tutt said:


> I wired up the motor with the Y scheme and it worked perfectly!  I couldn't get it to pull the rated current no matter how hard I pushed the drill press.  The motor barely got noticeably warm to the touch.
> 
> i remember looking for a delta or y on the name plate.  I never could find anything.  Now that I look again the frame is "56y".  Is that the designation or just a coincidence?  I figured that was just for the dimensions of the motor.
> 
> ...



The “Y” that is shown as a part of the frame size generally means that the motor has a special mounting configuration. It's not usually an indicator of Star connection. But if it works as Star then you've solved your problem (well one of them, anyway)

Incidentally, is the center-line of the motor shaft 3.5" from the base of the motor, and the shaft is 5/8" dia? They are often values that 56 frame size motors use.


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