Replacement Unisaw Motor

[Dennis Hellon]

I'm new to Sawmill Creek so hopefully I'm doing this correctly!

Just assembling my used Unisaw for the first time from a complete tear down, rebuild, restoration (1979 model so not to terribly old). Some parts were missing, such as the dust shield in front of the blade, some tapped holes were damaged and had to be helicoiled but all in all just very dirty.

When I went to start up the saw for the first time the overload assembly on my motor starter keeps tripping. Testing the motor one motor leg is pulling 100 amps while the other is only pulling 16 amps as the tag says it should. Checked the wiring it is correct and neither lead is jumping to ground. Could take the motor to work and have the leads Megger'ed but figure no point since pretty sure it's shot anyways. So now I'm looking for a new motor but where is a good source - good quality motor for a good price?

I can find a Leeson Unisaw motor on Ebay for $350 with shipping but I've never cared for Leeson motors, in industrial plants I've always found them to be CHEAP motors that don't last long and run hot. Any other sources?

[Mike Henderson]

I believe the Unisaw has a special mounting so you can't use a standard motor. Why not get the existing motor re-wound? It might even be less expensive than a new motor.

Mike

[Jamie Buxton]

Plaza Machinery offers a Baldor 3 hp single phase for the Unisaw for about $400 including shipping. http://www.plazamachinery.com/

[Rollie Meyers]

I bought a 3 HP 1Ø Leeson for a little bit over $300.00 and a unisaw motor has a uncommon mounting means.

http://www.electricmotorsite.com/pc/sglwood_unisaw/120728

[Bruce Page]

Dennis, Mike’s suggestion of getting the existing motor re-wound is probably your best option. The Unisaw motor mounts are unique so your replacement options are limited. Expect to pay ~ $300-400 for a new one. I have seen them sporadically on Craigslist & Fleabay.
BTW, I have 3 Leeson motors in my shop and have never had a lick of trouble from any of them.

[Rollie Meyers]

I prefer OEM but do not like paying for OEM:mad: although Baldor was used as a orig.equipment motor on unisaws before , I dispise Baldor motors as they take a dump too quick for my tastes, I chose Leeson for that reason, but if one were to do a little research you would find that Baldor & Leeson share some common heritage.


Rewinds can be costly do some research on new VS rewind.

[Dennis Hellon]

I forgot to mention that the keyway on the shaft was a little worn out. The previous owner told me that every week he had to tap the key back into the keyway on the drive sheave. When I tore down the saw I found both set screws missing on from the keyway on the sheave. That couldn't have been a problem you think?? I did replace the set screws but since I'm just firing up the saw for the first time now I have no idea if they will hold in the key.

So the question is, should I still consider rewinding the motor?

[Bruce Wrenn]

Price the rewind, and while shell is being rewound, take shaft to a machine shop and have them cut another key way. Takes longer to support armature and find center of shaft than it does to cut key way. I have had this done on several motors over the years. If you can scratch the shaft with a file, then an end mill can cut a new key way. Do a search in the classifieds here and on Woodnet and see if someone has a take off 3 phase motor.

[Greg Sznajdruk]

I'm new to Sawmill Creek so hopefully I'm doing this correctly!

When I went to start up the saw for the first time the overload assembly on my motor starter keeps tripping. Testing the motor one motor leg is pulling 100 amps while the other is only pulling 16 amps as the tag says it should. ?

Bruce:

The 100 amps got my attention right quick; I'm assuming that this is a typo.

Greg

[Pete Bradley]

What do you mean by one leg and the other leg in your measurements? It sounds like this is a single phase motor, there should be two leads with one path through the motor.

I'm assuming you've checked the obvious, like the motor turns freely when installed in the machine?

This motor sounds pretty beat on, I think it's borderline for a rewind.

Pete

[scottj owen]

I have a unisaw that had some shipping damage, I think the motor is in excellent shape, if your interested email me at sowen@platinum.ca and I can give you more info. Thanks Scott

[Dennis Hellon]

The motor turns free, no issue with the bearings that I can tell. As far as the amperage, I took my clamp on amp meter and put it on the T1 lead of the motor. Next I hit the start button, the motor began turning but not at full speed and the amp meter showed 100 amps just before the overload assembly dropped out the holding contact on the starter. Double checked this measurement several times and it is correct. Then I checked the T2 lead of the motor and it pulled 40 amps initially before dropping down to 16 amps again just before the overload assembly dropped out the holding contact. The FLA of the motor is 16 amps. Again double checked the amperage off the T2 lead several times and it's correct.

Kept thinking about this one and it hit me, this is a capacitor start motor. Basically the cap dumps it's charge into the motor windings when the motor starts up so that the motor doesn't pull so much amperage when starting up. If the cap is bad the motor will pull high amps. So I yanked the capacitor off the motor, discharged it, and sure enough it tested bad. I'm thinking I should be able to find a new cap for fairly cheap.

As far as the shaft, I'm going to see if I can do some horse trading at work and get a new keyway cut into the shaft 180 degrees off of the existing one. Good idea Bruce! Like you said it will take longer to set of the mill and chuck up the armature then it will to cut the keyway.

[Dan Marcus]

I also bought a 3 HP 1 phase Leeson as a replacement and the cord has a white, black and green wire. I am confused as I expected a red, black and green. I am unsure how to wire this motor. Can anyone help me out?
Dan

[Matt Hutchinson]

I recently did some research into replacement motors for my Unisaw. Jamie's link to Plaza Machinery (http://www.plazamachinery.com/) has the best deal I could find on new Baldor Unisaw motors. Plus he also has a bunch of used motors for a lot less.

I have no connection or affiliation with him, nor did I even purchase from him. I got lucky and found a used motor locally.

[Jason Neal]

Hi Matt, please note Dennis's original post was almost 3 years ago. Hopefully he has it sorted out by now ;)

[Matt Hutchinson]

Whoa! Lol, I missed that. Never mind then. :P