Thread: How do you slow down an electric motor?

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sounds like the same belt sanded like i have .i do not run the disc sander any more after having the same thing happen to me .there was a sound coming off the sanding disc look over and BANG 80grit sanding disc to the face hit me so hard it look the the safety glasses off my face hit me in the lip and teeth so hard i was thinking i open my lip up. it was stringing could not tell at first . but i did not do any thing to my good looksbut i did get very sick looking at the safety glasses .if i did not have them on i would not have the use of that eye . you can not slow it down to much with out hurting the tq of the sander the ac motor needs to run at max rpm for tq if you cut it down with a speed controll it may not work as good . i have a ac motor machine with a frequency drive on it did not work that hot step it down with pulleys .it still needs more tq .with a dc motors work better with a controller and you can turn up the tq at low rpm i have used the baldor and the danfoss drives

find any electric motor service company--they will know what wires to couple to change speeds or voltage

I also have a 6x48 belt sander with 12 in disc (belt driven) but I don't use the disc anymore---too many times a slight change in where you are sanding will change the force direction and you'll lose your hold on whatever your trying to sand/grind. And the belt sands in a straight line vs circular for the disc--makes it easier to control finish of what ever your working on

That might be the thing, just forget that the disc is there and use the belt only. Even that part is a little intimidating because it whips around pretty fast too. But at least if the belt breaks (which has happened twice already......but that is because the top roller bearings are loose and letting it wobble a little at max speed) it won't do the damage the flying disc will. I really would like to get this thing working right as it removes metal like right now.

I thought of calling an electric motor shop as you suggested and asking them what can be done to the motor to slow it down.........I think I'll try that. Funny part is, the 76 year old man I bought it from earned his living using it for the past who knows how many years. Maybe he just ducks faster than we do.

Don