391 replies to this topic

[MSwiss]

You just don't get it.

My flat track has never "killed" a 4002FK. The car just doesn't go.

On 28 amps/12v, the other cars are affected.

On 200 amps/13.1v, they aren't.

But on the heavy-wired King, they either, pop( sometimes with a tiny bit of smoke) and still run fine, they pop and run at about 80%, or the least common, they melt the endbell, like you showed, and IIRC, always on the back side.

[swodem]

Pop?

[MSwiss]

The noise from an electrical failure.

And your comment,"Yes, the motor could be OK-fast..."

You made that statement based on what? Experience with running an eliptical comm before?

You wonder why I've been less than polite in this exchange? You're making outrageous statements, with zero data to back them up.

[Zippity]

"the backside"?

 

Nearest the axle? North or South magnet?

 

(We wire our tracks with positive on the left hand braid in the direction of travel.)

 

[MSwiss]

Towards the back of the car, like in the picture in post #1.

What I see as the positive on a stock 4002 FK.

[swodem]

The noise from an electrical failure.

And your comment,"Yes, the motor could be OK-fast..."

You made that statement based on what? Experience with running an eliptical comm before?

You wonder why I've been less than polite in this exchange? You're making outrageous statements, with zero data to back them up.

 

Mike, if you don't want to be polite don't participate in my thread. I haven't been rude to you.

 

Any comm that needs truing is by nature elliptical.

 

Have I had motors with a blown stack? Yes, they didn't run too bad, in fact I have considered running these in an FK F1 flat track car to stop the chattering axle bounce.

 

The theoretical motor as I described that may have a low point on the leading edge of a comm segment simply has a pole that's more retarded. Nothing stopping it being fast. It's possible the early stages of this exhibit push starting, and as the comm arcing in the course of running continues could create a build-up that eventually bridges two segments, causing the melting short? Who knows? I don't, thats why I have raised it and thats what I am trying to uncover.

 

I haven't made (m)any statements, only suggestions.

[MSwiss]

"That's not getting brush contact on one comm segment when it should - hence no short."

I clearly debunked that in post #21.

Dozens of times, on the low amp supply, a motor didn't start, and each time it affected the power on the other lanes.

IOW, opposite your theory, the brush is making contact.

If you can't figure out by my experiences running a raceway for 12 years, and using every version of a cheap Chinese motor for at least some length of time, that I'm certain the common denominator, is the heavy cogging neo magnets, accentuated by the small comm and tall brushes, there is nothing more I can add to this.

PS: Find a "push-start" 4002FK. Install a ceramic mag can on it. I guarantee the "problem" will go away.

[swodem]

I might also 'introduce' terribly awry brush hoods, and see if this makes for a push-start.

Have you tried the ceramic magnet thing? I went to install F7 magnets in one once but they're thicker and needed honing...

[MSwiss]

No, on the ceramic mag thing, but before the Hawk 6 and Proslot 4002FK, the only motors I've ever seen that need a push start are ones with a dead pole, or possibly ones with out of spec timing (50 degrees +).

[MSwiss]

I might also 'introduce' terribly awry brush hoods, and see if this makes for a push-start.

 

Now you are thinking clearly.

With some of the dissected, failed motors, guys have commented, despite aligning the hoods, how out of whack the curvature of the brush face is.

Good night.

[swodem]

Well, I can understand that, I have seen it too, as the hoods typically are not snug fitting and the arm is pulling the brush face along with it as it rotates. Many of my old brushes are longer on one edge, until I started blueprinting the hoods.

Proving I can't leave a bone alone, I have no life, and four hands, I set about understanding exactly what is going on at the comm face

Attached images speak volumes - no short-circuit with new, well aligned brushes due to the cut off extreme edge.

But... no way getting around a short-circuit with 'run-in' ones though....

New unused:




Well used

[Zippity]

Great photographs, Steve.

[NSwanberg]

I think you may have the brush on the right reversed in the well used photo. The trailing edge of both brushes usually gets pulled around the commutator.

[swodem]

NSwanberg, the brushes are not off that motor.
 
Indicative only, but makes the point, aye?
 
Neither set-up pics were perfect.

[gotboostedvr6]

That comm is clearly an indicator of a curmudgeon. If I've never seen one before, and trust I haven't, that example is of one.

[Pablo]

Swodem may find my post #82 HERE of interest.
 
I'm no electrician, but I do know it does funny things sometimes.
 

 
The solution to the problem came to me at 2 in the morning:

- A clove of garlic tied to your controller handle with catgut.
- A sprig of parsley wrapped around the positive lead wire.

No more push-starts.

[Richard G With]

I think Steve's picture tells the story, for what I've experienced anyway.

 

I recently pulled a car out of storage and hooked it up to a power supply to check it.

Initially, it wouldn't start at 5 volts and I observed black gummy deposits on the comm. Shot it with WD40 (not suggesting that as a tip, it was handy). Motor began working normally.

 

My conclusion in this case is that I'm over-oiling the comm bushing. Had similar problems with a car that I sent to Dallas. It never stopped, just ran slow.

[swodem]

I wouldn't put WD40 on the comm...

[MSwiss]

My conclusion in this case is that I'm over-oiling the comm bushing. Had similar problems with a car that I sent to Dallas. It never stopped, just ran slow.

 

When a motor is new, after oiling the pinion end, without resqueezing the bottle, I touch the end of the needle to the comm side, and let capillary action draw the tiny bit on the outside surface of the needle, to that junction of the shaft and bushing.

I might repeat, once a race, tops.

[Richard G With]

I wouldn't put WD40 on the comm...

 

WD40 is the fallback when duct tape won't do the job. IMHO.

[Zippity]

Can't remember when I last put duct tape on my comm.  

[swodem]

Zip, when was the last time you even saw your armature? Hahahahaha.

[gotboostedvr6]

I knew Zip was a curmudgeon.

[Zippity]

Ran an even faster time tonight with my new C43 and 4002 motor

 

No push starts either...

[swodem]

What lap times?