OT---Electric motor

Jiles · Apr 25, 2014

I have a drill press with a new looking 1 HP GE motor. The motor has a plate on the rear end with instructions for changing rotation.
I have a start problem and it will rotate fine in whatever direction it decides to.
Upon starting, sometimes it will just hum and then it will start.
It will not start at all with belt hooked up.
It looks to have a governor of some sort in the rear of the motor but I haven't torn it apart. Motor has not been used in many years but spins free and is clean.
Buy a new motor or could this be a simple fix?

Dick2 · Apr 25, 2014

Most common problems are: 1) Corroded contacts on the centrifugal switch. Mark the position of the end bells to the frame on both ends (with different marks on the opposite end). then take the end bells off on the switch end. Sand the contact points and re-assemble.

2) Faulty capacitor (if motor has a capacitor). CAREFULLY remove the capacitor cover, then short a screwdriver across the terminals of the capacitor to discharge the electrical charge.

Momentarily plug in power cord (2 seconds will be sufficient), then use the screwdrive across the terminals. If there is a good spark, the capacitor is good; it there is no spark, the capacitor is dead. DO NOT touch the terminals until you have discharged the capacitor. Some people have suffered heart attacks from the jolt from a charged capacitor.

Other possible causes could be a burned/shorted starting winding, but you should have smelled that if it happened. Bad bushings could also be a cause, but you should hear a growling when it tries to start if the bearings are worn.

John T · Apr 25, 2014

I agree with Dicks good suggestions. A single phase split phase motor does NOT know which direction to spin if voltage is applied to the run winding so it may just sit there n HUMMMMMMM. The separate out of rotational phase start winding gets it initially spinning subject to how its wound and then its disengaged via the centrifugal switch contacts which are initially closed until X RPM at which time they open so its out of the circuit. If the switch contacts are burned or not closing that can cause no starting and HUMMMMMMMM so Id check that fer sure. As far as a start capacitor (discharge it first), to straight steady DC it should appear as an open circuit once charged up but it initially conducts current until charged...The connections on those can get loose and burned and carboned also even with a still good capacitor....

John T

jennifer408 · Apr 25, 2014

(quoted from post at 11:27:18 04/25/14) Most common problems are: 1) Corroded contacts on the centrifugal switch. Mark the position of the end bells to the frame on both ends (with different marks on the opposite end). then take the end bells off on the switch end. Sand the contact points and re-assemble.

2) Faulty capacitor (if motor has a capacitor). CAREFULLY remove the capacitor cover, then short a screwdriver across the terminals of the capacitor to discharge the electrical charge.

Momentarily plug in power cord (2 seconds will be sufficient), then use the screwdrive across the terminals. If there is a good spark, the capacitor is good; it there is no spark, the capacitor is dead. DO NOT touch the terminals until you have discharged the capacitor. Some people have suffered heart attacks from the jolt from a charged capacitor.

Other possible causes could be a burned/shorted starting winding, but you should have smelled that if it happened. Bad bushings could also be a cause, but you should hear a growling when it tries to start if the bearings are worn.

question, first you say touch the terminals with the screwdriver, then you say don't touch the terminals, discharge it first. when you touch the screwdriver on the terminals the second time it discharges the capacitors, right ? so when you say, DO NOT TOUCH THE TERMINALS, do mean like don't touch it with your tongue ? discharge it with the screwdriver first ?

Zachary Hoyt · Apr 25, 2014

I think a screwdriver with an insulated handle is assumed in this
case.
Zach

TomH in PA · Apr 25, 2014

"so when you say, DO NOT TOUCH THE TERMINALS, do mean like don"t touch it with your tongue ? discharge it with the screwdriver first ? "

I am intrigued by your comments and would like to subscribe to your newsletter. Also, stay away from electric fences...

Dick2 · Apr 25, 2014

DO NOT TOUCH the terminals with any part of your body until you have crossed the terminals with an insulated screwdrive. That jolt can be a very unpleasant experience - if it doesn't kill you!

If you doubt yourself, take the motor to an experienced repairman.

Jiles · Apr 25, 2014

I took the motor apart. Everything looks new and from the looks of the new aluminum step pulley, I dought it has run 30 minutes.
It does not have a capacitor---so I didn't even have to worry about touching my tongue to it--- LOL.
Contacts looked new but I cleaned a little with 400 grit paper.
Same problem but I let it run for about 15 minutes and there was no overheating or burnt smell.

Frank 41 · Apr 25, 2014

I thought all 1P motors have capacitors.

Jiles · Apr 25, 2014

(quoted from post at 03:00:13 04/26/14) I thought all 1P motors have capacitors.

This motor is stamped 1 HP I don't believe it is correct because I have never encountered a 1 HP motor this small with 1/2" shaft. Also it is about the size of a large coffee can??????
I would guess it is closer to 1/4 HP ??

Jiles · Apr 25, 2014

Here is a little additional info:
MAX DEV HP 1.0
5XBJ00C D HP SPL

Anyone know what I have?

Dean · Apr 26, 2014

No.

There are multiple single phase motor designs. Some use capacitors while others do not.

Dean

Geo-TH,In · Apr 26, 2014

If motor has a hot smell, you should always measure the amp draw. You can get good cheap ammprobe at HF, I have one, better than old analog.

If your current is in specs, and you have a humming problem, check for scratches on rotor. Usually scratches indicate bad bearings, however I've seen cheaply made motors where the rotor is out of round. Put it in lathe and true it up.

It's also possible you have short in windings, windings will be black. Or it may not be wired right.

buickanddeere · Apr 26, 2014

Looking isn't going to accomplish very much.What is needed is an ohm meter and trace the start circuit out. To ensure it is in the circuit when the motor is initially energized. Then the start circuit is opened when the motor reaches approx 70% of rated rpm.
Reversing is achieved by swapping the polarity of only the start windings.

Jo Bird · Apr 26, 2014

Neighbor has one like that we just give it a spin in the direction we want it to go. It's second nature now, been that way for about 10+ years, still waiting for it to quit completely.

OT---Electric motor

Jiles

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Dick2

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John T

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jennifer408

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Zachary Hoyt

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TomH in PA

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Dick2

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Jiles

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Frank 41

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Jiles

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Jiles

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Dean

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Geo-TH,In

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buickanddeere

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Jo Bird

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