Mark V just cleaned and now blows breaker?

[bgstraughan]

My Mark V started to hum again so I took it apart, blew out all the dust, put it back together again and it worked for about 20 seconds then it blew the breaker. It usually only blows the breaker during the wonter if I have forgotten to reduce the speed before shutting it off last time. Any ideas from you would be appreciated. Thanks

[beeg]

when was the last time ya Oiled it? Your knot using an extension cord are ya?

[JPG]

Explain what you mean by hum 'again'.

If that is a recurring problem and the 'humming' is for longer than a few(less than 5) seconds, the run windings may now be bad.

When it 'hums' does the shaft turn?

What was it doing for 20 seconds?

Blowing it out may have put crud in the start switch.

What did you 'blow out'? Headstock? Motor?

[bgstraughan]

Thanks for your reply. You are right about the extension cord. I've always used an extension cord with no issues so didn't think of it. Unfortunatly a cord is necessary in my garage. Might have to try a shorter one. The motor has permanently sealed bearings so other than oiling the pully areas not sure what you mean. This is a brand new issue in a machine that has been used a lot in the last 30 years.

[bgstraughan]

Explain what you mean by hum 'again'.

If that is a recurring problem and the 'humming' is for longer than a few(less than 5) seconds, the run windings may now be bad.

When it 'hums' does the shaft turn?

What was it doing for 20 seconds?

Blowing it out may have put crud in the start switch.

What did you 'blow out'? Headstock? Motor?

Thanks for your reply.
It was humming because it was not turning but electricity was getting through to the motor.
I blew out everything and it took a while for the dust to stop coming out of the motor. Kept moving it around and changing the direction the air was coming from so I could get as much out as possible.
When it was on for the 20 seconds it was turning a small drill bit in drill press mode.
Added a little white lithium grease to the top of the motor, where you remove the black head so you can get to the inside of it. The old grease was looking pretty used up.

[beeg]

Might have to try a shorter one. The motor has permanently sealed bearings so other than oiling the pully areas not sure what you mean.

Use a 12-3 gauge extension cord. Ya need to oil the motor sheaves and the control sheaves about every 10 hours with 6/8 drops of oil.

[JPG]

Explain what you mean by hum 'again'.

If that is a recurring problem and the 'humming' is for longer than a few(less than 5) seconds, the run windings may now be bad.

When it 'hums' does the shaft turn?

What was it doing for 20 seconds?

Blowing it out may have put crud in the start switch.

What did you 'blow out'? Headstock? Motor?

Thanks for your reply.
It was humming because it was not turning but electricity was getting through to the motor.
I blew out everything and it took a while for the dust to stop coming out of the motor. Kept moving it around and changing the direction the air was coming from so I could get as much out as possible.
When it was on for the 20 seconds it was turning a small drill bit in drill press mode.
Added a little white lithium grease to the top of the motor, where you remove the black head so you can get to the inside of it. The old grease was looking pretty used up.

Grease? Black head? Old grease?

Do realize that 'humming' with no rotation is destructive.

Shorter extension cord is 'good', but bigger wire size(#12) is better.

It is possible it did not get up to normal running speed in 20 seconds and that caused the tripped breaker.

[beeg]

Just thought of this. What was the temp in storage?

[john_001]

I don't know much about motors, so I'm just shooting from the hip - could the OP's motor have a shot capacitor? I had the same symptoms with a window A/C - humming, dimming the lights and taking a long time to start and eventually not starting at all - and it was a bad cap.

[beeg]

I don't know much about motors, so I'm just shooting from the hip - could the OP's motor have a shot capacitor? I had the same symptoms with a window A/C - humming, dimming the lights and taking a long time to start and eventually not starting at all - and it was a bad cap.

VERY Doubtful! Out of hundreds of check/replace the capacitor, only TWO was the problem. Have ya cleaned up and oiled the SS, and blown the dust out of the motor? What gauge of wire to the outlet and your knot using an extension cord. What else is on that circuit?