humming motor

a1gutterman · Post by **a1gutterman** » Sun Jan 24, 2010 10:58 pm

buck50bmg wrote:You do know that its "not" and not "knot" right......just trying to help.

buck50bmg wrote:Thats "cute".

Wow you people need to steep back from the computer and use your shopsmith some more.....

I guess I can knot spell. So sorry.

pickarni · Post by **pickarni** » Sat Sep 11, 2010 10:08 am

------------------------ wrote:Okay! So after I checked all the wires (connections were good) I flipped the motor in the mounts and looked inside the wiring compartment in the tail of the motor, I noticed that the contacts were about 1/8" away from each other, so I took a small screwdriver and bent the stationary side until the gap was about 1/32". gave it power and it fired up nice with no hum. I let it come to a stop and flipped the switch and it fired again perfectly. After doing it about 10 times, I called my humming motor fixed. Thanks guys! Now what have I done wrong????
Mark

I have the same problem that you had with the humming motor. I recently bought a 1987 Mark V 510. It worked probably for 30 starts and then I was using the drill press and it just loudly hummed when I tried to start it. Can you explain how you flipped the motor in the mounts? What all did you have to take off in order to get to the motor? I am not as mechanically inclined but am hoping it is only the gap of the contacts like yours so I don't have to send my whole motor in to Shopsmith. Any help would be much appreciated.

dusty · Post by **dusty** » Sat Sep 11, 2010 10:29 am

pickarni wrote:I have the same problem that you had with the humming motor. I recently bought a 1987 Mark V 510. It worked probably for 30 starts and then I was using the drill press and it just loudly hummed when I tried to start it. Can you explain how you flipped the motor in the mounts? What all did you have to take off in order to get to the motor? I am not as mechanically inclined but am hoping it is only the gap of the contacts like yours so I don't have to send my whole motor in to Shopsmith. Any help would be much appreciated.

If your motor is humming and not smoking it is doubtful that it needs to go to Shopsmith. Besides, Shopsmith does not do motor repair. If anything, they will send it to a motor shop which you can do. The best thing about that is getting it repaired at a local motor shop eliminates a lot of time delay.

Blow it out, check to see if it has lubricating holes, if it does give it a couple drops of oil and put power back on it to check it out.

pickarni · Post by **pickarni** » Sat Sep 11, 2010 10:46 am

dusty wrote:If your motor is humming and not smoking it is doubtful that it needs to go to Shopsmith. Besides, Shopsmith does not do motor repair. If anything, they will send it to a motor shop which you can do. The best thing about that is getting it repaired at a local motor shop eliminates a lot of time delay.

Blow it out, check to see if it has lubricating holes, if it does give it a couple drops of oil and put power back on it to check it out.

I just adjusted and aligned everything prior to this happening. Do I have to take off the sheaves and belts and everything?

dusty · Post by **dusty** » Sat Sep 11, 2010 12:40 pm

pickarni wrote:I just adjusted and aligned everything prior to this happening. Do I have to take off the sheaves and belts and everything?

Most probably not. Removing and reinstalling the drive belt is not that much trouble and it does not effect alignment.

If you have not done so already, I recommend that you view at least Sawdust Sessions #21 thru #24. These lessons give you the basic knowledge required to do this task.

http://www.shopsmithacademy.com/Sawdust_Sessions.htm

Just take your time. Be constantly aware of power. In other words, unplug it!

pickarni · Post by **pickarni** » Sat Sep 11, 2010 12:42 pm

dusty wrote:Do not start the process by replacing the motor. In fact, if you still have it, you should probably drag it back out for a check up.

Readings between the lines, I think that your motor is good. At least it is neither shorted nor are the field windings open.

The failed Shopsmith motor that I have experience with was visually defective and you could smell it as well. The field windings overheated and shorted out.

My approach would be:

Remove the drive belt from the motor. This removes all mechanical drag and instantly eliminates the mechanics of the Mark V as the cause.

Blow all the dust out of the motor. This can best be done with the motor running but that may not be possible. The dust, if it is the cause of your symptoms, is in the contacts of the start switch which prevents power from being applied to the start capacitor and start windings. Dust in the motor will not otherwise cause it to not start. I have worked on some really dirty, dust impacted motors than ran fine. Being excessively dirty reduces the flow of air thru the motor and subsequently causes it to over heat and maybe burn out.

Check the power cord for general condition and measure the voltage across the black and white wires where they connect to the motor. Insure that all power connections are secure. Excessive voltage loss can occur as a result of loss connections (at the switch, at the motor, at the plug).

It is now time to plug it in and turn it on with the drive belt still removed from the motor. It should turn on and come to run speed very quickly. You should be able to turn it off and then back on repeatedly and repeatedly experience the same quick start.

Now turn it on and let it run. It should run with no detectable variance in speed. The speed control does not work with the belt removed. No not change the speed control setting now as doing so can cause serious mechanical damage.

After doing all of this, you should be able to declare whether or not the motor is in need of repair/service based on the observations made.

NOTE: It is possible for a defective on/off switch (high resistance contacts) to cause the symptoms that you are experiencing.

Where do I find the contacts of the start switch so I can know if they are what is causing the problem? Thanks.

dusty · Post by **dusty** » Sat Sep 11, 2010 4:21 pm

pickarni wrote:Where do I find the contacts of the start switch so I can know if they are what is causing the problem? Thanks.

Other than to tell you they are inside the motor I can't help you. The motors are not all the same and I don't know where except on my own motors.

JPG · Post by **JPG** » Sat Sep 11, 2010 4:43 pm

pickarni wrote:Where do I find the contacts of the start switch so I can know if they are what is causing the problem? Thanks.

Which brand motor do you have?

pickarni · Post by **pickarni** » Sat Sep 11, 2010 4:45 pm

I have an Emerson 1 and 1/8th Horsepower. I thought I read in another post that you have an Emerson.

JPG · Post by **JPG** » Sat Sep 11, 2010 5:06 pm

pickarni wrote:I have an Emerson 1 and 1/8th Horsepower. I thought I read in another post that you have an Emerson.

Yes! The contact is barely discernable. The motion is very small. The contact is shaped like a bell which makes it impossible to actually 'see' the contact area. The contact is on the terminal board under the wiring access plate. It may be possible to check the 'made' condition of the switch with from there. It has been a while since I had mine apart, but the parts that move are visible(not easily so) so you should be able the find ohmmeter contact points to check the switch(one of the capacitor wires is connected only to one side of the switch). Since the contacts are concealed, and if the contacts are NOT made 'at rest', then blowing them or vibration may be the only thing to try.

I realize this is vague, but I do not think I took any pix when I had mine apart.

Shopsmith Forums

humming motor

More Info Please.