kd-12 timer motor surgery

[soberleaf]

i was asked to post pics of the kd-12 timer motor as it looked after i took it apart using my dremel to grind off the 4 points where it was riveted together. here they are. i was going to try to rewire the little motor but a friend on this site has a timer for me so i can forget that idea. the wiring is extremely fine, varnished wire, and although it is probably available out there somewhere i'm not going to pursue it at this time.

at least i now know what a timer motor looks like on the inside! i will put it's parts in a plastic bag and keep them as a reminder that although i did not succeed in fixing this motor i learned from it. besides, it would seem almost sacrilegious to throw away a kitchenaid part!

first pic, timer motor before surgery, showing the raised "bumps" that i grinded off using a dremel and a cutting wheel.

 

[soberleaf]

timer motor in halves

here are the two halves of the timer motor after i made the cuts with the dremel. the motor winding unit just popped right off.

 

[soberleaf]

all the parts

here are all the parts to the winding unit, the winding itself, they all came out easily with the help of an extremely small and sharp pointed screwdriver.

 

[soberleaf]

try that again

picture please!!! where the hell is the pic??? oh here it is!!

 

[soberleaf]

the coil itself

here is that little tiny coil, bet rewinding that would be fun! have no idea how to do it but if i could wire that small i think i would try anyway!

 

[soberleaf]

coil housing

coil fits in here. note lack of wire leads on above pic of coil itself, i broke them off long before that pic was taken. so much for trying to get that coil to work again!

 

[soberleaf]

gear and stator

guess this is called the stator, correct me if i'm wrong here guys, it's not an armature, anyway it's a gear on a magnetic disk that gives the timer motor it's ability to turn anything!

 

[soberleaf]

another part

the above mentioned gear/magnetic disk whatever fits inside this part.

 

[soberleaf]

kinda back together

here it is with the gear disk back on the shaft surrounded by the above mentioned part. i have no idea what any of these things are called and i even left out a part, that little round cover with all the holes in it. could not get it to fit back in properly but it basically mounted directly over the coil before the 2 gear parts went on.

so anyway that's how to rip apart a kd-12 timer motor if you don't care about ever using it again! i wanted to see what it looked like inside and already had a back up plan for a timer so i said what the hell, no guts no glory!

 

[gansky1]

A Singer sewing machine bobbin. Who knew?

 

[jetcone]

Yes Greg

A bobbin for sure. That spikey disc is the stator field coils, the field being induced into it by the coil below. That will cause a rotating field in the stator which will cause the rotor& gear to turn. No field no turn OR no lube no turn.
Thanks for posting I have always wondered what was inside, I had looked at patents but they are way more detailled than this little motor.

 

[fltcoils]

Very nice, thanks for posting.

Most likely the coil is simply a circular winding. So it could be rewound the same way. Circular turns around the bobbin. But I'm only guessing.

My weakness is curiosity about coils, since I design DC solenoids. Lots of visions of magwire and turns dancing in my head.

If it moves it is the armature.
If it is stationary it is the stator or pole piece.

syncronous motors are fun because they don't need the numerous separate windings that one finds in an induction motor. I think that's how it is, and certainly that's how the picture appears. The breaks in the "fins" of the pole piece plate, stator plate and armature will work with the AC flip flopping magnetic field out the coil ends to make it turn around.

So a fix for this might be to find the coil magwire size, if it is bad (check with ohm meter), and rewind the coil with simple circular turns (I think it's that simple for this one). There are AWG charts showing wire diameter vs standard sizes, drawn from drill sizes I believe.

But you earlier said that the coil was 1000 ohms, which means that it is still good....

 

[fltcoils]

Syncronous motor design, cool

The trick is how the stator has regularly spaced fins, but the armature has irregularly spaced fins. That allows the simple "bar magnet" 60 hz magnetic field from the simple bobbin wound coil to induce a torque. A Tesla thing I suppose. simple Genius.

My point in all this is that the electrical side of things is very simple. The failure in this piece is mostly a mechanical problem. worn armature bearing (that brass extruded gear stock piece) and lub that's gone.

Lesson:
Don't throw out timer simply because motor is kaput.
with fewer suppliers repairing these we might be able to find a way to repair them.. with care.

If we want these to remain "automatic" appliances, then we probably should get good at lubricating these armatures and gears in the motors. Rewinding these simple circular-around-a-spool coils would also be helpful.

Thanks again, Peter, for a good lesson.

 

[soberleaf]

thanks

i'm gonna keep it, filed away in a baggy in my dishwasher repair room, alias extra bedroom. it's a dishwasher heaven in there, motors, racks, pumps, control panels, you name it. i'm sure heaven will be like that too, hydrosweeps and power towers and streets of harvest gold abounding!!!! and ofcourse hell will be full of "energy savor" and "energy star" dishwashers! frigidaires too!

i can't even find where the wire leads came off at, i broke them off the first nite i started taking it apart. and i agree if i could find some super fine wire i could probably rewire that little bobbin of a coil. if i ever find it i will actually try.

i have contacted several timer motor places i found on e bay. one, a feisty fellow in arizona never returned my e mail but he seems like the type who would do that, from his web postings about not "wasting his time" etc. oh well, life goes on!

the other company i had high hopes for but they say they have no timer motors with an output gear like mine, which is 10 teeth and about 3/16 in diam and 3/16 in length. i was surprised at that one. i told them i thought a 50-60 rpm motor would do and i was sure they would come up with something for me. they didn't.

i have got various old timers off old dishwashers i have long thrown away (non kitchenaids ofcourse) or otherwise found and one of these nites i will pull a few motors off them to see if i can get one to fit this kd-12 timer. this timer may live yet!

and again if not my friend "gansky1" on this site has contacted me to tell me he has a timer from a kd-12 for me! i am very appreciative of that and can't thank him enough, so if you're out there gansky1, thanks again, you are wonderful and if i can ever help you with your collection please ask! i do have a lot of stuff myself. just weak in the kitchenaid timer area.

thanks

pete