speaking of vibrations... from my motor

[Steve Tiedman]

My 22 year old Vicmarc VL200 (mamma bear model) uses a 1.5hp, 180 volt output (240 volt input) Leeson DC motor and Minarik DC controller drive, the typical Vicmarc/Woodfast setup for many years from Craft Supplies USA. It's always been a casual/hobby use machine. But some vibes I feel through the machine I've isolated to the motor, to the point that not only the belt is off, the motor pulley is off and the motor vibrates a bit, enough to feel it easily through the machine.

Motor mount is tight and secure in all aspects.

This is a brush-type motor. Could wearing brushes be the cause of motor vibrations? Although I can't discount shaft bearing, they sure feel good.

Could I be feeling the armature entering and exiting the magnetic fields?

I'm not even a motor novice, and I realize DC has not been discussed here in forever thanks to 3-phase VFDs. But if anyone with good motor experience can share some nuggets of wisdom, I'd appreciate it. Thank you!

 

[Don Wattenhofer]

The simplest check would be to look at the brushes to see if they are worn down to a point where they don't have enough spring pressure to keep them in contact with the commutator or they are so short they are tipping in their guides. The other thing to check would be the edges of the brush the leading and trailing edges should have a nice clean edge, but if it shows signs of arking then you may have shorted coils in the armature. The brush caps are usually accessible without dismantling the motor.

 

[Steve Tiedman]

Thanks Don, I'll look into these things.

 

[Steve Bonny]

I would also check the lathe is sitting correctly - all 4 feet evenly loaded. Any vibe issues can be exaggerated if the lathe is sitting on 3 feet.

 

[John K Jordan]

vibes I feel through the machine I've isolated to the motor, to the point that not only the belt is off, the motor pulley is off and the motor vibrates a bit,

I'd be taking it apart to examine, look for anything unusual, check the windings. If nothing obvious, there are electric motor shop all over the country.

 

[Steve Tiedman]

I would also check the lathe is sitting correctly - all 4 feet evenly loaded. Any vibe issues can be exaggerated if the lathe is sitting on 3 feet.

Great point, and it is. I have a floor that is anything but placed in one plain. Everything in my shop has to be very carefully leveled and loaded after being set in place.