Weird sander problem...

[Kevin Beitz]

Today i had a strange problem... I put down a new floor in my home and I was using a belt sander to sand the floor. I had this great idea of hooking my my central vac to the exit to the dust bag on my sander. When I turned the sander on it would not run with the vacuum turned on. Made no sense to me. if anything it should have run faster. Even if I turned on the sander first then the sander it would stall the motor right out. Any ideas?

[Ole Anderson]

Running a 12 amp vac and a 6 amp sander on the same circuit could be the problem. Try running the vac on a different circuit.

[John K Jordan]

Today i had a strange problem... I put down a new floor in my home and I was using a belt sander to sand the floor. I had this great idea of hooking my my central vac to the exit to the dust bag on my sander. When I turned the sander on it would not run with the vacuum turned on. Made no sense to me. if anything it should have run faster. Even if I turned on the sander first then the sander it would stall the motor right out. Any ideas?

A universal motor or an induction motor? Is it possible the vacuum on the impeller blades is strong enough to pull the motor out of phase with the stator windings, enough to mess with the rotating magnetic field? I can't say I've ever even imagined that possibility. I'd have to ask my friend Joe, he knows everything there is to know about motors.

[John Goodin]

Could there be a trigger switch to prevent people from using the sander without the bag in place?

[Kevin Beitz]

Not a voltage drop... Every time I pulled the hose away from the sander to motor would pickup speed. The vacuum would pull down the sanders motor dust fan. But you would think that the fan would be turning the same way as the vacuum pull.

[Carl Beckett]

Try putting it on the blower side of a shop vac and see if the same thing happens?

Some impellers (wondering if your sander has impeller vanes) have a full backing plate for manf (most smaller ones). When a pressure differential is across this (from inlet to outlet sides), it creates a thrust force. Often pushing against a thrust bearing.

But wondering if the vacuum on the outlet pulls it the opposite direction, thus not having a thrust bearing to support it in the axial direction, and stalling out.

(dreaming up stuff so take it with a high dose of skepticism...)

[Kevin Beitz]

Universal motor... No ​trigger switch... The motor is stalling...

[Bill Dufour]

Does the motor rotate under vacuum with no power? Try it both ways with the vac.

[Jim Andrew]

What brand and model is the sander?

[Kevin Beitz]

No blower side... Central vac... The blower side is out side of the house...