sander woes-part two

larry merlau

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18,741
Location
Delton, Michigan
well when i had peter here, we diagnosed the ROS sander that dies on me.. we have come to the conclusion that its the winding.. so here is what it does.. you start it up and winds up to speed ok. but as soom as you place on the wood it has no power, this is a 2 amp motor and the other one is a 1.7 amp motor and they both have alot of hours on them but the 1.7 actually has more as it was the first one here.. so you sparkies out there what gives a motor power and is this fixable? the armature and brushes look ok got a little blacking on the armature but peter said it was normal..
 
Larry, I don't believe it's a motor problem. The sanding pad rotation is free-floating. The sanders motor has no direct connection to make the sanding pad spin. The sander motor turns a counter-weight (eccentric housing), which the sanding pad is attached by a ball bearing (or bearings on some models). That bearing is mounted off-center to the axis of the counter-weight. As the motor rotates the counter-weight, the center of the sanding pad moves in a small circle around the axis of the counter-weight. The sanding pad is free to rotate on the ball-bearing, in reaction to friction created between the pad and the work piece. Some models also include a pad brake feature to limit maximum pad speed. This brake consists of an o-ring that provides resistance to pad rotation.

I've fixed 2 different brands in the past by simply replacing the belt{actually an o-ring imo}, they stretch due to use &/or heat {usually caused by too much applied pressure during use}, and occasionally dust build-up on the ring can cause them to glaze over and allow slippage. Anyways take this with a grain of salt until those with more experience chime in.
 
well ken i have replaced the belt and the pad and it still wont work.. i will bring it along next time i am in your area, which looks like the wknd of the 7th. and you can see if yu can get it working..
 
my problem rob isnt that i need to have this sander running its that i got paper for it and its brother i already have a couple bosch sanders that i use regulary but this sander is good for job site use..
 
Sorry Larry but I'm confused after re-reading this thread...
When you say "you start it up and winds up to speed ok. but as soon as you place on the wood it has no power," are you implying that the motor has no power or that the sanding pad has no power? Just trying to clear my head on which end is the likely culprit.
 
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