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Electrical Motor issue - need some guidance

Duker

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Sep 25, 2010
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Livingston, TX
I have a Powermatic 1150 drill press that was running fine when I moved it to temporary storage to clear some floor space while working on some projects. I loaded it back in to my truck and brought it home and now all I get when turning it on is a hum from the motor. I tried to be careful but I may have knocked something loose.

I checked that I have full power to the switch and since that seemed to be OK I then hooked up power directly to the motor leads and get the same hum. I am thinking that it might be a capacitor issue but this far from my expertise so wanted to see if I might be missing something else.

If it is the capacitor, is this something I can order easily and if so any recommendations where to order it from.

I have included a picture of the capacitor if it is of any help.
 

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12ozd

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at the kegerator
I had to replace the one on my lift motor, I got it from graingers.
They were the most expensive, but it was in stock and I got it the next day.
IIRC about $25.00?

The flash wiped out the rating no's.
Can't see them.
 
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Duker

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OK was surfing through Grainger and here is what comes up when using the 216-259 code.

http://tinyurl.com/llol9hb

I don't know if physical size in a capacitor makes a difference (yeah I could see the jokes coming...) but when I limit to the 110-125 capacitors they are all smaller than what is on the drill press. The capacitor on the motor now is roughly 4 3/8" x 2 1/4" which matches closer to the 220-250V ones. This is new territory for me so trying not to buy the wrong one.
 

lametec

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Could be the centrifugal switch is stuck or corroded as well.

If you turn the spindle by hand when the motor is humming, does it start turning by itself? And if so, do you hear a slight click from the motor as it spins up, and another one as it's about to come to a stop?

Most likely it'll be the capacitor, but checking the centrifugal switch for proper operation is free.
 

TractorJeff

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Physically moved it, to storage, then back?
For $8, I would change the Cap also.
If not, then try spinning motor shaft to get it rolling.
As the centrifugal switch could have jounced a spring or corroded and stuck.

I recently changed a cap on a drill press motor.
It was running, stopped, changed bit.
DONE! No worky!!!! Seriously!!
Luckily being a hoarder, I had a spare in stock on the shelf, just had to thoroughly troubleshoot first to verify it was the Cap.
 

G_P

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You can run a higher voltage cap if thats what you find. The voltage rating on a cap is just its maximum voltage.
 
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Duker

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Guys I appreciate the help. Unfortunately it appears it is not the capacitor. I bought both a 120 and 240 volt capacitor (figured it would come in handy if I switched the drill press to 220.) I tried both capacitors in case one was bad and the get same hum from the motor. I am referring back to your other suggestions but need some more help as I have no idea what a centrifugal switch is on the motor nor where to find it. I have googled it but I am not sure if I need to pull the motor apart to see it nor to try and fix it. When it comes to electrical motors I am a total noob.

Could be the centrifugal switch is stuck or corroded as well.

If you turn the spindle by hand when the motor is humming, does it start turning by itself? And if so, do you hear a slight click from the motor as it spins up, and another one as it's about to come to a stop?

Most likely it'll be the capacitor, but checking the centrifugal switch for proper operation is free.

Lametec - The motor will not start even if I turn the spindle while turned on. I can't hear any clicking noise however.


Physically moved it, to storage, then back?
For $8, I would change the Cap also.
If not, then try spinning motor shaft to get it rolling.
As the centrifugal switch could have jounced a spring or corroded and stuck.

I recently changed a cap on a drill press motor.
It was running, stopped, changed bit.
DONE! No worky!!!! Seriously!!
Luckily being a hoarder, I had a spare in stock on the shelf, just had to thoroughly troubleshoot first to verify it was the Cap.

TractorJeff - yeah it was in a storage unit for a for a couple of months and I moved it laying down in the bed of my truck.

You can run a higher voltage cap if thats what you find. The voltage rating on a cap is just its maximum voltage.

GP thanks I bought two capacitors just in case I decide to re-wire it to 240 which it has the schematic for on the drill press.

If its the cap. It might start if you give the spindle a spin by hand after turning it on.

Yep tried that and no luck.

I may be over my head in this one but am willing to give it a shot if the fix is fairly simple. I have another drill press but it is jigged up for another project and I hate to tear it down to drill the holes I need for my current project.
 

lametec

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Have you removed the belt form the motor to see if the motor spins on its own?

While the belt is off, make sure the motor actually spins freely.

If it does spin freely, and if it still just hums, you can try giving the pulley a spin in either direction to see if it gets going.
 
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Duker

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Livingston, TX
Have you removed the belt form the motor to see if the motor spins on its own?

While the belt is off, make sure the motor actually spins freely.

If it does spin freely, and if it still just hums, you can try giving the pulley a spin in either direction to see if it gets going.

OK, took the belt off and sure enough it starts up and runs. I put the belt back on and the minute any tension is applied from the variable pulley it bogs down and stops. I am at a loss as to what changed or why it wont run as it did.
 
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Duker

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Well .... problem solved.

I could not figure it out... with the belt off everything turned freely. In fact when the motor turned off the drive pulley would spin after power was off for over a minute. Which by the... kudos to the line worker at Powermatic in TN who did a nice job of balancing the pulleys.

I finally decided to pull the motor off and start to tear it apart which considering my motor expertise is akin to saying I am throwing in the towel (and I am only doing this to justify buying a new motor), but I figured what did I have to lose. I pulled the plate on the bottom of the motor and noticed that one of the wires was off kilter to the connector. Upon closer inspection I found that it was attached to the connector with just 1 little strand of copper the size of a thread. So, after putting on a new connector and checking every electrical connection again.... I now have a running drill press.

Lesson learned. Check connections all the way through to the terminals next time versus just the leads.

Thanks again to everyone for your suggestions and help. It was great quick education in electric motors. I will be a little more prepared for when I have to rebuild my Delta 17 which needs new bearings and a complete overhaul.
 

TractorJeff

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Elkhorn, WI
Well?
Congratulations!
Sometimes we ALL do that!
Instead of thinking simple, we ask and get a million opinions/suggestions.
Follow those and get frustrated because the problem isn't cured!
I'm a thinking everyone "***-u-me" that the connections were ALL good!
Including me!
 
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Duker

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Livingston, TX
Well?

Congratulations!

Sometimes we ALL do that!

Instead of thinking simple, we ask and get a million opinions/suggestions.

Follow those and get frustrated because the problem isn't cured!

I'm a thinking everyone "***-u-me" that the connections were ALL good!

Including me!


TractorJeff, I think I am extra guilty of that!

Duker you are going to take our jobs. Good work !


Rookie, no fear of that. I burned a few hours of a vacation day that I had planned to use on another project trying to solve that issue an I am am sure a good electrician would have found and fixed that problem much much sooner. I think I will stick to my day job! :)

The bright spot is that it is fixed and it was a beautiful day here in Houston to work in the shop!

Again, a big thank you to everyone who took their time to respond.
 

MixManSC

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Jan 6, 2014
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Location
South Carolina
Good to hear you figured it out. Having worked on computers for many years - I became "that guy" that friends and family would call all the time with any sort of trouble. I found the best solution was to put them off - tell them "too busy right now, it will be a day or two but in the meantime try googling what you just told me". 98% of the time they call me back happy to brag that they got brave and looked in the device manager or whatever, figured out the problem and fixed it themselves.

Point is - given a bit of time and enough gumption to dig in one will very often find that something is not as complicated or intimidating as it might seem. Of course with electrical a measure of caution is also in order.

If you do ever suspect a starting issue - spinning a motor by hand gets it going.... the centrifugal starting switch is a spring loaded device that cuts power to the start capacitor (or start windings if its a self starting motor) when the speed of the motors rotation overcomes the strength of the springs which in turn opens the circuit. It will generally be on the electrical connection end of the motor attached to the end of the shaft. Just have to remove the one end cover on the motor and you can usually see right there on the end of the shaft.
 
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