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Dead Motor, Rewind or Replace?

Cannonmn

Stainless
Joined
Jun 25, 2016
Spindle Motor for K&T 2D rotary head mill needs repair/replace. Been lucky so this is first time faced with repair/renewal of a motor. I think I'll be unlikely to find a new or working Doerr 3/4 hp with proper case shape required for mounting in this mill. What kind of money am I looking at to have this Motor rewound, if I can find someone willing? The Motor has 9 wires for connecting to high or low voltage per the diagram, which I mention since it may impact cost of the work. I only plan to run it on 208v./3 phase, if it will run on that with overheating. I think the low voltage it is designed for is 220v/3 phase. I've never had this machine running, I bought it with the bad Motor.

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As-is it states 208-220, not that it does you any good. But it was made to run on 208.

Out of curiosity, what is bad about the motor? (aside from it evidently not running..... I mean shorted, open, bad smells, etc)
 
As-is it states 208-220, not that it does you any good. But it was made to run on 208.

Out of curiosity, what is bad about the motor? (aside from it evidently not running..... I mean shorted, open, bad smells, etc)

Wish I knew. When I bought the mill as a spare parts set for another 2D I'm using, the Motor was disconnected, unbolted, resting in the built-in locker on right side of mill. That all pointed to dead Motor removed pending repair that never happened. No I haven't connected it to power to test it, at least not yet, didn't seem necessary.
 
That all pointed to dead Motor removed pending repair that never happened. No I haven't connected it to power to test it, at least not yet, didn't seem necessary.

Might be a wise move to NOW at least get a meter onto those leads.

Could be in good-to-go shape - removed to get at some OTHER deviltry.

That said..a mere 3/4 HP? For K&T, that was usually a K&T-subsidiary (for a time) Walker-Turner drillpress size. K&T wannabee-but-not-quite "Quartet" mill uses a 3/4 HP for knee traversals, 5 HP horizontal spindle, 1 3/4 HP, 3 HP, or 5 HP for vertical spindle.

You even sure that it IS a spindle motor for your machine?
 
Might be a wise move to NOW at least get a meter onto those leads.

Could be in good-to-go shape - removed to get at some OTHER deviltry.

That said..a mere 3/4 HP? For K&T, that was usually a K&T-subsidiary (for a time) Walker-Turner drillpress size. K&T wannabee-but-not-quite "Quartet" mill uses a 3/4 HP for knee traversals, 5 HP horizontal spindle, 1 3/4 HP, 3 HP, or 5 HP for vertical spindle.

You even sure that it IS a spindle motor for your machine?

Yes, There's an empty space in the machine where it goes, and the unusual bolt pattern on shaft end bell matches hole pattern in the Motor mounting ring. But I'll post the Motor specs from the 2D parts manual and you can compare to the Motor data plate, which I haven't done yet; pls advise if they aren't at least pretty close.

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Yes, There's an empty space in the machine where it goes, and the unusual bolt pattern on shaft end bell matches hole pattern in the Motor mounting ring. But I'll post the Motor specs from the 2D parts manual and you can compare to the Motor data plate, which I haven't done yet; pls advise if they aren't at least pretty close.

?? Seems you could do THAT without need of even an internet connection?

:)

Meanwhile .. a K&T with no more spindle-power than a latter-days Bee Pee round-ram Emm-head, and HALF that of a tiny Burke #4 does seem a bit out of the ordinary.
 
If you get lucky, maybe a Doerr motor with a standard frame can provide a transplant of the center section with the windings to your end bells and rotor. Ask this eBay seller for the length and outer diameter of the center section of his motor.

Doerr Electric S6117J Motor 3/4hp .75hp 1725/1425RPM 28-22/44Volt 3ph | eBay

Larry
Thx Larry, I've sent those questions to the seller. Btw what a collection of high-ticket stuff he's got; always wonder how much stuff high-ticketers like that really sell. I don't even know what some of his stuff does.
 
"?? Seems you could do THAT without need of even an internet connection?"

I think your comment relates to my invitation to anyone to compare manual's Motor specs with those on data plate. To those in the know, I probably sound like the world's laziest A.H., but in fact the reason is that if you have as little knowledge of motors as I do and are just doing word and alphanumeric matching, the manual and the plate do not match. I suspect the apparent mismatches are insignificant, but I can't be sure.
 
?? Seems you could do THAT without need of even an internet connection?

:)

Meanwhile .. a K&T with no more spindle-power than a latter-days Bee Pee round-ram Emm-head, and HALF that of a tiny Burke #4 does seem a bit out of the ordinary.

Anyone wondering about why some design trade offs were made in the model 2D might want to watch this 1955 video by K&T entitled "From Print to Product." Was digitized by member ramsay1 in 2015.

Kearney Trecker 2D Tool and Die Mill Jan 14, 1955 16mm Film - YouTube
 
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That said..a mere 3/4 HP? For K&T, that was usually a K&T-subsidiary (for a time) Walker-Turner drillpress size. K&T wannabee-but-not-quite "Quartet" mill uses a 3/4 HP for knee traversals, 5 HP horizontal spindle, 1 3/4 HP, 3 HP, or 5 HP for vertical spindle.

You even sure that it IS a spindle motor for your machine?

The rotary head has a very small spindle with equally small collets, IIRC 3/8" max ?
 
The rotary head has a very small spindle with equally small collets, IIRC 3/8" max ?

Collets for the 2D rotary head mill go up to 3/4 inch. A few different-size collet-holders are used between spindle and collet, so someone who bought a used machine with only the smallest of those holders remaining might have told people that the machine only takes up to 3/8", but that person would have been incorrect.
 
I worked for an outfit that rewound motors. Cost to rewind was around half of new cost, down to a certain HP (3-phase,2 HP, I believe). It doesn't matter what frame type or voltage. That said, if it is old and irreplaceable, then price probably doesn't matter much! Smaller motors weren't economically feasible to rewind, for the most part.
 
I worked for an outfit that rewound motors. Cost to rewind was around half of new cost, down to a certain HP (3-phase,2 HP, I believe). It doesn't matter what frame type or voltage. That said, if it is old and irreplaceable, then price probably doesn't matter much! Smaller motors weren't economically feasible to rewind, for the most part.

Thanks, after reading that I called my local rewind shop and asked if he could give me a gross cost range est and he agreed to try doing so from the photos, so I should have that info today. You are correct about "old and irreplaceable" so given what I have in the machine and my plans for it, I have a threshold of pain of about $500 in mind. My other 2D is at home, and this one is in the shop, and it'd be nice to have working 2D's at both my metalworking locations.
 
Ok, shop responded with ballpark $1500., about what the whole machine cost, but everything in this area is expensive so not too awful shocking. But they also gave me test procedure I can do with my ohm meter, which I'll paste here in case some other poor bastard wanders onto this thread some day wanting to check same motor or another one with 9 wires:

"OHM Test readings should be the same value
1-4 Circuit together, but nothing else
2-5 Circuit together, but nothing else
3-6 Circuit together, but nothing else
7-8-9 Circuit together, but nothing else
NONE circuit to ground or casing"

So I'll plan to test it today. I have a bad feeling that the light brown dust around the casing joint in the Motor is burned insulation but forgot to ask repair guy about it.
 
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Messy test record. It passed everything the rewind guy said to check including that no wire had a circuit with any other except as specified in his list. So now I'll make the connections for 208/3 and test-run it. If all's well there I'm back to wondering why he pulled the Motor out and cut the wires And Lost A small Bushing along the way (grrrr!). If I had it to do over again I'd thumbtack or staple every wire to a strip of plywood, in numerical order, and write numbers clearly on the wood. All those connections needed in the test can be confusing otherwise.
 
Ok, shop responded with ballpark $1500., about what the whole machine cost, but everything in this area is expensive so not too awful shocking.

Yeah, I was thinking that 3HP break even point sounded a few years out of date. I bought a used air compressor a year or two ago that turned out to have a bad motor, 10HP, and the local motor shop flatly stated that he couldn't be competitive on motors 10HP and less. That was pricing against new catalog price for the replacement. I lucked out with a new-old-stock Baldor motor off fleabay for $150, but that was a common motor.

Dennis
 








 
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