Saving the 5HP Kinamatic DC Motor

[Phil in Montana]

When you are done with the undercutting use some of the purple scotch brite to polish... works real well...Phil

 

[rabler]

When you are done with the undercutting use some of the purple scotch brite to polish... works real well...Phil

Thanks, I’ll give that a try.

 

[9100]

The armature has more commutator bars than slots, so it has some form of multiplex winding, which is used to give more smaller increments to torque. If convenient, see if the brushes are exactly 180 degrees apart or shifted half of one commutator bar from each other. That is the difference between taking steps with one foot at a time instead of jumping with both together. One more way to make a smooth running motor.

Bill

 

[Phil in Montana]

Bill have you ever worked on a dc motor or rewound one?? What you just wrote is from the outer-limits...Phil

 

[DDoug]

I see the stator is varnished on the outside, and the end bells still have grey paint.
Someone has been inside this motor before, maybe just dunked the stator
in varnish, maybe more.

 

[rabler]

The armature has more commutator bars than slots, so it has some form of multiplex winding, which is used to give more smaller increments to torque. If convenient, see if the brushes are exactly 180 degrees apart or shifted half of one commutator bar from each other. That is the difference between taking steps with one foot at a time instead of jumping with both together. One more way to make a smooth running motor.

Bill

I was wondering about the winding. (I know nothing about motors from an engineering perspective). I did pull out my Fluke meter to test the resistance between adjacent commutator bars, thinking that would be a good way to verify I'd cleaned up between the commutators reasonably. Adjacent bars seem to be about .2 ohms, increasing by about that much for each bar. Thinking about it, it makes sense to have some sort of staggered winding that gradually steps the current between windings rather than cutting one off and the next one on.

 

[rabler]

I see the stator is varnished on the outside, and the end bells still have grey paint.
Someone has been inside this motor before, maybe just dunked the stator
in varnish, maybe more.

That someone gets my award for being a total asshat. This is the cooling fan rotor. Note the ding on the upper right, and one the bottom there is a fairly good bend. Someone obviously pried the back end off by prying against this fan rotor. It is about 3/8" out of true. Not sure how I'm going to fix that but I'm sure that isn't helping the motor's balance.

 

[Phil in Montana]

The whole winding is in series, probably 3 coils per slot, it could be progressive or regressive but make no difference unless you are going to rewind it... I would leave the fan alone, not much could be gained unless you replace the fan, with the belt drive on the ee I don't think you will tell the wobble is there Phil ...Phil

 

[DDoug]

That someone gets my award for being a total asshat. This is the cooling fan rotor. Note the ding on the upper right, and one the bottom there is a fairly good bend. Someone obviously pried the back end off by prying against this fan rotor. It is about 3/8" out of true. Not sure how I'm going to fix that but I'm sure that isn't helping the motor's balance.

That's not very nice.....The fan mangling might have come later.
The fact that the stator has been re-varnished (either plain dunk or VPI) shows it went
to a real motor shop at one time.

 

[9100]

Bill have you ever worked on a dc motor or rewound one?? What you just wrote is from the outer-limits...Phil

I have worked on lots of them, beginning in 1951 when I got a summer job in the P. E. Chapman Electrical Works at 1820 Choteau in St. Louis. I got a basic education, really basic. Penrose Embry "Pappy" Chapman was a crazy old coot, but a smart and extremely penurious one. Their product was armature winding, taping and soldering machines. They didn't sell motors and transformers as products but made them for their machines. Chapman salvaged old transformers and cut the laminations down by hand. My first job was cutting them on a square shear. Besides being oily, the pieces had bad burrs and my hands were masses of little cuts. I then graduated to painting machines, stacking laminations, and prepping armatures, fitting paper in slots, etc. Because I was 15 and Missouri law required a powered machine operator to be at least 18, I never got to actually wind an armature but saw it done and worked on the machines.

I had a Kabar lock back knife that I learned to open with one hand, useful when I had wires in my left hand needing stripping. Unfortunately some folks thought the skill belonged in West Side Story rather in a factory. As Chapman said when he regretfully told me that I was not invited back the next summer, they objected to "my penchant for dangerous weapons and dexterity in their use." We stayed friends, though.

The experience has been very useful since. I have rewound lots of electrical items, mostly transformers and DC motor field coils, and have a vapor pressure inpregnation chamber. I treated a lot of locomotive fuel transfer pump motor armatures. They would absorb moisture and flunk a megger test. I would bake them and leave them in a vacuum overnight to remove virtually every trace of moisture, then let transformer varnish in to cover the armature and let in air pressure to force the varnish into every space, then bake them to cure the varnish. That usually would bring the megger reading to infinity.

So yes, I have worked on a few motors

Bill

 

[rabler]

Is it worth trying to revarnish anything? My inclination is not to mess with it more than necessary, but it is apart now, so this would be the time to do any other work on it. Still haven't ordered in new bearings, need to pull the reduction gear apart to see what is in there that might need to be replaced before doing that.

 

[rabler]

Well shit. This DC motor is going to take a bit of work to get it reliable. First, the large reduction gear from that gearbox. Obviously that gear is not far from complete failure.

Second, the wiring inside the motor is in rough shape. If you look closely at the lead with the eyelet, the insulation is cracked from heat, and at the tie the underlying copper is exposed. That copper is pretty badly tarnished. Someone had been in there with electrical tape trying to patch up some of that. Since these are the brush leads, I figured they'd be easy enough to replace. They should just run straight out as the armature leads, A1 and A2.
Not so, those leads are wired with the two smaller field poles in series, then the brushes. F1 and F2 go to the larger laminated poles, as do S1 and S2, as well as leads labeled 2 and 3, which are interconnected in the peckerhead. Total of 4 leads to each larger pole. Haven't completely mapped out how everything interconnects yet.

This is enough of a mess that I'm going to have to step back for a while and decide if I want to keep pursuing this route. Nothing insurmountable, just more than I was hoping to have to deal with as far as the motor and gearbox. I've already turned the commutator and replaced most of the bearings

 

[texasgeartrain]

You sure seem to break a lot of stuff lately.

Hey, if it was easy, it wouldn't need you to fix it.

Not sure on the wiring, I'd have to lay an eyeball on it. But the gear, you could have a ring gear made. Turn the teeth down on current gear. Then press ring gear on.

What's the mating gear look like ?

 

[TBJK]

You can heat shrink the wiring. That’s probably what I would do after cleaning it up. To clarify the good heat shrink.

 

[rabler]

You sure seem to break a lot of stuff lately.

Obviously I need to buy more tools to have the things to fix them, right?

Hey, if it was easy, it wouldn't need you to fix it.

Not sure on the wiring, I'd have to lay an eyeball on it. But the gear, you could have a ring gear made. Turn the teeth down on current gear. Then press ring gear on.

What's the mating gear look like ?

Mating gear is in good shape. This ones not very hard.

 

[rabler]

You can heat shrink the wiring. That’s probably what I would do after cleaning it up. To clarify the good heat shrink.

Given the corrosion in the wiring, I'm thinking I'll cut out that section, solder splice in a new wire, and heat-shrink over the splice.

 

[Cal Haines]

I think I would first see what a local shop would charge to redo those leads and maybe re-varnish the coils while they're in there. Then you'll basically have a new motor.

Cal

 

[rabler]

I'm going to keep my eye out for a spare 5HP Kinamatic DC motor for these. I'm going to fix this one up eventually, but at this point having a spare seems prudent.

 

[rabler]

I think I would first see what a local shop would charge to redo those leads and maybe re-varnish the coils while they're in there. Then you'll basically have a new motor.

Cal

Haven't done anything with this one in a while. It has sat on the bench. I'm going to take it to a motor shop near me when I get a chance (the long round-to-it list). In retrospect I should have dealt with the DC motor first before tackling anything else in the drive system, but not having a working DC controller got me started down the wrong path. Hindsight, a VFD conversion would have been more straightforward, and not really any more money than I will have into this when done.

 

[rabler]

Update:

Just located a couple of new GE 5 HP KinaMatics... plus a few more, used.

Could be cheaper than motor shop? Surely less cost than a stout VFD + AC motor would run?

email me?

Bill,
I’ll email, and a compatible replacement would be great! Just remember we’re looking at a custom built Kinamatic in the 10EE with the integrated gearbox, in addition to RPM and armature voltage. Sure, all of those can be worked around, but that takes time. I’ve already passed the effort level that *to me* would justify having just gone with an induction motor and vfd if I were starting from scratch. I’m not, and have invested considerable effort in an improved front end for the Parkers, so I’d like to try to see that to completion.

Sure, cheap electrolytic capacitors will die after a few years. A better vfd with decent capacitors should last 10 years under my usage. At which point a replacement vfd is pretty easy to drop in, if I’m still around to do it. If not me, it’s pretty straightforward for anyone with a bit of programming skill. Certainly easier than diagnosing any problems with a custom DC controller, which even the basic Parker approach is as far as the 10EE. I haven’t given up on getting mine running with the DC motor and gearbox, but I’m trying to be clear to other forum participants that it may not be the ideal approach for them. Especially as many of them may not have electrical engineering degrees or mad scientist inclinations.