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Swapping Stators on 3ph motor, 1/3hp to 3/4hp? Gorton 1-22 Knee Motor

dalmatiangirl61

Diamond
Joined
Jan 31, 2011
Location
BFE Nevada/San Marcos Tx
The winding leads on the knee lift motor on my Gorton mill are toast, probably from soaking in oil for too long. I have located a similar enough (same mfr, voltage, rpm, frame) used F56 frame motor, but it has a keyed shaft, and is 3/4hp vs the 1/3hp with spline shaft. Can I just swap out the armature? Will it have the power of 1/3 or 3/4hp? I'm thinking it would consume power of a 3/4hp motor, but maybe not have the power of a 3/4hp motor? Shipping the existing motor out for repair + return shipping would cost about the same as a used motor delivered, and take much longer.
 

texasgeartrain

Titanium
Joined
Feb 23, 2016
Location
Houston, TX
The hp will come from the windings. Assuming the armature has the same dimensions, I would think it would work, but I think thats a large assumption without seeing it apart. Any motor will need x amount of hp to start up and run based on its mass, but won't actually be running at full hp, or full amps. Its more of what it is capable of doing. As load is applied, amps rise. The amps and volts will let you know how much hp its pulling.

The amps rating for that motor's switches or contacts may need to be verified as you would be going bigger and start up amps higher, but 3/4hp is not all that big.

My only other concern might be if you crashed or hit a stop of some sort, the 3/4 hp might break more stuff, lol.
 

dalmatiangirl61

Diamond
Joined
Jan 31, 2011
Location
BFE Nevada/San Marcos Tx
The hp will come from the windings. Assuming the armature has the same dimensions, I would think it would work, but I think thats a large assumption without seeing it apart. Any motor will need x amount of hp to start up and run based on its mass, but won't actually be running at full hp, or full amps. Its more of what it is capable of doing. As load is applied, amps rise. The amps and volts will let you know how much hp its pulling.

The amps rating for that motor's switches or contacts may need to be verified as you would be going bigger and start up amps higher, but 3/4hp is not all that big.

My only other concern might be if you crashed or hit a stop of some sort, the 3/4 hp might break more stuff, lol.

I went ahead and ordered the motor today, either its going to be an easy cheap fix, or a $100 lesson. The 3/4hp motor is off some machine, no idea what, but I'm pretty sure it will work. Tearing the gearbox apart for a rebuild today, looks like a wise choice, bearings are crunchy, and found a 3 piece roll pin. Looks like the roll pin is what is supposed to give before the gears.

Edit: The parts donor motor Doerr 60341 F56cz 3ph 3/4hp 1725rpm 208-220/440v-ac Ac Motor | eBay

Edit again: Note to anyone else that finds themselves rebuilding the gearbox. There are 2 bearings in the end of the snout, you cannot just drive them out the front, you have to remove outer bearing first, then remove a snap ring, then remove inner bearing.
 

dalmatiangirl61

Diamond
Joined
Jan 31, 2011
Location
BFE Nevada/San Marcos Tx
Donor motor arrived today, I am now 99% sure this will work, won't know that last 1% till power is applied. Stator case length is the same, rotor dia is the same, visually it appear to be same rotor, only difference is in the shaft and rear bearing (I can use old rear endbell).

Notes: There are 7 bearings in this assembly, 2- 201 bearings, and 5- 203 bearings. A ball joint pickle fork worked quite well for removing the bearing from the intermediate gear cluster.

Bearing question: Dug thru the bearing stash last night and found 2- 6201 bearings, they fit fine. Found 1- 6203 bearing (.625" bore), and 2- 203 bearings (.670 bore), all have the same O.D.. What I need is the .670 bore, according to interweb search, and sellers ads, 203 and 6203 bearings should be the same, what am I missing?
 

johansen

Stainless
Joined
Aug 16, 2014
Location
bainbridge island
there are occasionally special bearings of a standard metric OD and thickness but imperial inner diameter.

A 203 or 6203 bearing is 17mm inner diameter which is very close to what you measured of .670"


as for the motor i'm pretty sure it will work but i would expect it to have high no load losses due to mismatched rotor/stator air gap. but you might get lucky. you can reduce the voltage a bit with some small 24v transformers if needed, but it sounds like this is intermittent use anyways.
 

dalmatiangirl61

Diamond
Joined
Jan 31, 2011
Location
BFE Nevada/San Marcos Tx
Arrrgh, it turned into a $100 education today, and not for a reason I had anticipated. The housing for the stator is correct length, but the windings are too long, in an application where you were using an endbell this would not be a problem, but with the Gorton gearbox it is.

Not finding a 1/3hp motor, got a ballpark quote for replacing leads on my existing motor last week, found a 1/2hp motor, think I'll double down on the education gamble:D.

Of note, the donor motor only had 3 leads, according to data tag that would mean it is 208-220v only. But iirc I have seen some 440v only motors with 3 leads, and considering age, maybe this was a re-wind done for 440v? Is there a way to determine what voltage a 3 lead motor is wound for?
 

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dalmatiangirl61

Diamond
Joined
Jan 31, 2011
Location
BFE Nevada/San Marcos Tx
New 1/2hp donor motor arrived today, looks like its going to fit. This is a 9 lead motor, with 3 extra wires that are not numbered. The green wire was bolted to ground on the case, ohm meter says there is continuity between the green, red, and white wires. Google search is telling me Doerr is dead, and Dumore Motors does not make induction motors. Google search is not showing any results beyond a few "for sale" ads on either the Doerr or Dumore P#s. My WAG is its a thermal switch, debating on wire nutting all 3 together, green back to ground and wire nut red/white together, terminate them individually? There is no continuity between leads 1-9 and the green/red/white leads.
 

dalmatiangirl61

Diamond
Joined
Jan 31, 2011
Location
BFE Nevada/San Marcos Tx
Had to turn a half inch off of each end of the stator and bore to fit end bell pilots, had to tape the wires to the expanding arbor to keep them out of the way. There was another pic, but damned if I know how to resize pics on the cell phone.
 

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dalmatiangirl61

Diamond
Joined
Jan 31, 2011
Location
BFE Nevada/San Marcos Tx
Its back together, just need to paint and reinstall. Had to cut lower edge off the data tag, it was that or remove it and leave the next poor sucker really lost. Last pic is the donor motor data tag.
 

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