I have a early 50’s uni-saw that if I remember is 1.5hp motor, I have had it for 18 of it’s years and has done quite well. In the last few months when I have found time to use it some times it will not start up like a bad start capacitor. But I don’t remember seeing any capacitors on the motor, has motor cover and to much of a pain to pull off to look.
Can hear the “hmmm” so turn off give the blade a push with stick, then hit power and away it goes. Guess could be a bearing, would need to remove belt tension to check that out though. Thoughts or comments
KK
Replies
Not a bearing. Could be a starting capacitor, but that would typically give you problems every time you started. The most likely cause is a bad starter switch which could cause intermittent problems.
The switch may just need cleaning up or it may have to be replaced, not that expensive in any case. Deal with it soon, those dead starts are tough on the motor.
John W.
If it's the "bullet end" motor it doesn't have a start cap. It's a repulsion induction motor that has four motor brushes under the outboard end bell. It could be a dirty commutator, worn brushes, brush holder moved out-of-time or a worn out spring that retains the copper "chicklets" for the start swich.
It's more than likely a Marathon motor. Good luck trying to find anyone at Marathon old enough to help. A few years back I contacted them for info about the same motor, was looking for a switch spring. They looked up the model number on microfich and said the slide was number 3, only 2 slides were older. It was faded and unreadable so they could not help except to say "buy a new motor". I was able to cobble up a new spring and all is well. A motor like yours is on eBay, will more than likely go for $200.
Dave Koury
Thanks for the reply Dave, It's been quite a few years since I had the motor cover off but think it is the bullet end. But I have slept several times since then also. Didn't think it had a capacitor, but I wasn't looking for one the last time was in there. will have to go out and open it up and take a look.
Hey dave, Got the old Marathon motor pulled out and tore down, Mine only has 2 brushes. Or I guess I should say should have 2 brushes, mine had a very small chunk of one and the other one was just in the form of dust! Called Delta and they said nope, find an old motor shop and you may be able to find something. Or they would sell me a new motor for $700!
Well I went to an auction yesterday and got an 82' Uni-saw with Biesmeyer and in like new shape for that same $700! But still gonna try to get some brushes and get this old dog back to barking!
Marsh
You could also buy a 3600 rpm motor, and replace the motor sheave with the smaller one, along with shorter belts.
http://woodworker.com/cgi-bin/FULLPRES.exe?PARTNUM=130-877
http://www.electricmotorwarehouse.com/woodwork_motors.htm Go halfway down the page to what they call "contractor saw" motors. They are really Unisaw motors, with the special mouting ears.
There are other sources that don't come to mind right now. Note that besides the special mounting, Unisaw motors have 3/4" dia shafts, which are non-standard.
Be seeing you...
Edited 11/1/2004 6:31 pm ET by Tom Kanzler
Only two brushes, are you sure? A four pole, 1725rpm repulsion motor has four brushes. The brushes are connected in pairs and sit in the holder. The holder can be rotated 180 degrees around the commutator. The brushes are a common size avalible from most any motor shop. Just don't purchase a harder grade brush. While it's apart, clean up the commutator and change the bearings, should be 204 bearings.
Dave Koury
Forgot to mention that I have a '48 Unisaw with that Delta $700 replacement motor. Paid $450 for the saw at auction. That's a special motor made by Marathon for vintage Unisaws with the oval motor opening. The motor is 10" long and 11" in dia. so the motor san be tilted into the cabinet base. A standard single phase Baldor 3600rpm motor is tooooo long to tilt past 15 degrees without cutting the cabinet.
DJK
Hi Koikid... If the saw has a 'magnetic start switch' check all the wires at the switch. Make sure all the screws are tight. Next, take an air hose and blow out the six years accumulation of sawdust within the switch. Take the air hose and blow out the same six years of sawdust from the motor. That cures 75% of starter problems. Many times, that is all that is needed. If the saw has a standard 'wall' switch SPST (single pole single throw) or heavy duty (DPST) (double pole single throw) replace the switch. It is far cheaper to replace a switch than a motor. SawdustSteve
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