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Post by phil on May 2, 2012 11:44:52 GMT -5
Hi all. When a motor gets old and loses it's torque, is it fixable or is t something like the core has lost it's magnetic strength? Could it be as simple as new brushes? Or??? Anyone have any experience in this area? New motors are so darn expensive I'd like to salvage this one if possible. Thanks! Phil
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Post by digdug on May 2, 2012 11:53:22 GMT -5
Phil if it sounds like its sparking or arcing and losing power, chances are more then often its your brush that is to thin or worn down. Sometimes they just end up really dirty in there and perform with same problem and a good cleaning can take care of it. Remember one thing really important.... If you remove the brushes to clean or check for wear, make positivly sure you put them back in the same direction and slot.
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Post by jakesrocks on May 2, 2012 12:14:23 GMT -5
If it's a brush type motor. take it apart being careful to keep all of the thrust washers in their right order. Clean the armature with fine sand paper and scrape out any crud between the segments with a sharpened piece of wood or plastic. Don't use metal for this. Put the motor back together. Put in new brushes, and give each end bushing a couple drops of oil. Hook it back up and run it. Those old motors will live forever with the right care.
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Post by Rockoonz on May 2, 2012 20:39:51 GMT -5
Could also be a capacitor if it's a capacitor type motor, if it has a cover on the outside with what resembles a large flashlight battery. Needs to be replaced with the same mf rating.
Lee
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Post by johnjsgems on May 3, 2012 11:11:30 GMT -5
There used to be motor repair shops everywhere. They could replace bearings and start switches very reasonably. Rewinding on small PSC motors commonly used on lapidary units is generally cost prohibitive. One thing that doesn't hurt is to occasionally blow out the motor to keep dust/dirt from building up inside.
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Post by phil on May 3, 2012 16:39:57 GMT -5
Thanks. I don;'t know what kind, just that it's a dayton 1/2 hp, 1725 rpm motor that came on our covington 10 inch slab saw. It just doesn't have any guts to cut much of anything anymore. Runs, but then comes to a dead halt with the slightest pressure. Does that help?
Thanks again, Phil
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Post by johnjsgems on May 3, 2012 21:11:30 GMT -5
Does it hum or trip the internal overload when it stops? If not it could be the belt slipping or a loose pulley. Also dress the blade. A dull blade can stall a good motor.
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quartz
Cave Dweller
breakin' rocks in the hot sun
Member since February 2010
Posts: 3,352
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Post by quartz on May 3, 2012 21:26:15 GMT -5
Sounds to me like it's running dry. Assuming a sleeve bearing motor: If relubable [most Daytons are], give it about 20 drops of good quality 20 wt. oil at the oil hole on each end. If not relubable, it can be disassembled and oil added to the wicks in the bushings. If a ball bearing motor, the bearings need replaced. The terms "sleeve" or "ball" bearings will be on the motor tag. Some years ago, my wife found a Lortone tumbler in a shed at an estate sale. It wouldn't run; the gentleman running the sale said probably "cold belt". She got it cheap, brought it home, and with a little oil in the lube holes it runs great.
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Post by jakesrocks on May 3, 2012 22:11:26 GMT -5
Try oiling it after cleaning it out real good. If that doesn't help, It might be cheaper to buy a good used motor. 1/3 HP should be plenty for a 10" saw. Any AC&R shop should have a pile of take out motors from old AC units that are still good.
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Post by phil on May 4, 2012 22:19:44 GMT -5
Thanks all! Not arcing or sparking. Runs, no hum. Not dry, no oil ports. Not the bearings/bushings so no false loading. Blade is brand new sintered one. Sooo... I talked to a few places that rebuild, estimates were $120 to $190. Talked to another shop who will sell me a new one for $84. Then talked to the manufacturer who said the motors are designed to last only five years or so. This one is 6 years old.... so I guess we'll buy the $84 one and hope it lasts another 5 years. Appreciate the advice..... I AM going to take the old motors apart to see why they died and to see what I can figure out.... Thanks again! Phil
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quartz
Cave Dweller
breakin' rocks in the hot sun
Member since February 2010
Posts: 3,352
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Post by quartz on May 6, 2012 8:52:36 GMT -5
Phil, Please do, put up your findings on the worn out motor, or motors. We can all learn from it.
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