3573 replies to this topic

[Alchemist]

The first com lost a plate (did you hear the cursing???)

I heard a slight ringing in my ears - but remember I'm on the other side of the "island" - LOL!!!

Thanks for offering to put up the pix - I really do enjoy the photos.

Ernie

[havlicek]

Here you go Ernie. I have no idea if this is good...correct...ugly...stooooopid, but it seems OK? To all you out there waiting for 5 pole rewinds, call somebody else



-john

[Alchemist]

Wow! Looks robust!!

That obviously looks like it took a while to do. It doesn't look as "svelte" as the usually 3 pole arm. Any idea on how powerful it will be?

Thank you for the pix John, they're always appreciated!

Ernie

[don.siegel]

Looks excellent John - and I hear they're looking for rewinders at the Pittman factory... Let us know how it "sings" when you power it up...

Don

[havlicek]

That obviously looks like it took a while to do.

Yes, it took a while to do "overall" Ernie. I tried to figure out some workable methods ahead of time, so I wound a few poles of the motor probably 3 or 4 times before actually winding it. When I finally did wind it "for real", that only took about an hour or so, but I had to leave off the com an install it afterwards which was difficult and took as long as winding the motor.

It doesn't look as "svelte" as the usually 3 pole arm.

Yes, they are chubby sonofaguns, having a larger diameter than even a 36D arm. Since I have no clamp large enough to hold this size arm, that meant holding it in my hand to wind it which made things even more difficult.

Any idea on how powerful it will be?

Not even the slightest clue Ernie:blink: Stock, these motors and similar (Pittman) are complete slugs but were once fitted in many old slot cars, so they still have appeal today for their historical significance. You really can never make these things into "screamers" so it's not worth the effort to go in that direction. Best to try for smooth torquey-ness. While I could have fit (squished) more wire on there, this wind shouldn't be at all "hot", but I'm in uncharted waters here.

Looks excellent John - and I hear they're looking for rewinders at the Pittman factory... Let us know how it "sings" when you power it up...

Thanks Don...Pittman can keep their job:) The only way for me to test this thing is to disassemble a working Kemtron sent along with the parts. I'm not sure whether I even want to do that...but maybe:unsure:

-john

[Jeff Buyer]

John,

That arm looks absolutely beautiful. What did you end up with in number of turns or length of wire?

JB

[don.siegel]

If you ever decide that you really liked the experience after all John, I've got extra parts.

Tomorrow: 7 poles!

Don

[Prof. Fate]

Hi

I hope this isn't my fault or that I forgot. With this type of leaf com, you start with rebuilding the com first, epoxying down the leaves and end piece first.

How fast?

Hmmm.

My surviving Kemtron in a Dynamic frame is a a 11 second/lap car at BP's king. All my STOCK 36d AMTs run low 9s and high 8s!

The 704 and DC65s are better on a lot of tracks than any of the Kemtrons and big pittmans as well. The primary success for these motors was in the drags at 36 volts!

Fate

[havlicek]

That arm looks absolutely beautiful. What did you end up with in number of turns or length of wire?

Hi jeff...and of course I'm most pleased you like it :-) The wind is "based around" 40T of #30. Of course, one turn on this arm (both because of the size of the arm as well as because you're going around two poles at a time) is probably somewhere near two turns on a 16D arm. So while the wire length is probably a little less than 80T of #30 on a 16D...it's still up there. When I say it's "based around" 40 T/#30awg It starts off at 42 for the first coil, then goes to 40 for the next three coils and finishes at 39 for the last coil. My theorey here was to try and use both the length of wire as well as the number of turns since equal length is important, but so are the number of turns since the strength of an electromagnet is proportional to the number of coils or turns. I'm going to install the arm in the Kemtron you sent to see how it all works.

If you ever decide that you really liked the experience after all John, I've got extra parts.

Tomorrow: 7 poles!

Don

I'm not sure this one will work Don...and even if it does, how long it will last since these coms are really spooky. Of course, if you need something repaired, I would always try and help. It's a lot less worrisome to go for the fix if the arm is fried in the first place...then there's nothing at stake;)

I hope this isn't my fault or that I forgot. With this type of leaf com, you start with rebuilding the com first, epoxying down the leaves and end piece first.

???I don't know how something here could be your fault Rocky. In any case, the second com has been epoxied at the top and tied at the bottom so I think it will stay together...maybe.

-john

[Afterburner Boyz]

John,
They look awesome! But seems to be more work than it's worth.

[havlicek]

Hi Andrew,

Once again, it was great meeting you last weekend (the sopressata only lasted about a day). The work is pretty steep on these things, but the good news is that I just got back up from the sanctum sanctorum after having installed the arm in the Kemtron setup I have here and it runs very nicely indeed. I only ran it at 6V, but it spins very smoothly and trying to stop the shaft with my finger gave me a friction burn...so I think the torque thing is fine too. The only hitch I ran into was that there is very little room for the com tabs to clear the brush tubes and I was as neat as possible soldering off the wires. I wound up having to put washers underneath the brush carrier/"endbell" thing. It would have been nice to have a couple more of the extra plate-spacers" , but this worked fine. The only thing that bothers me here is that I don't like having a motor run well when I have no idea why it does:laugh2: The com timing is really bizarre, but it seems to work...much better in one direction than the other.

-john

[havlicek]

I finished up Kemtron 5 pole arm #2. This one has a couple of turns extra on it...why?...I don't know, it seemed like a good thing to try:blink:



-john

[Prof. Fate]

Hi

Well I go on and on and on in these forums and if I forgot to mention something as basic as rebuilding the com FIRST...my fault. I am supposed to share.

With modern cheapo plastic car motors, the com thing is something I usually do as well if I am going to race the gullldarned thing.

Fate

[chaparrAL]

If only the lams where skewed ,then it would look like a windshield wiper arm. Nice work John!

[havlicek]

If only the lams where skewed ,then it would look like a windshield wiper arm. Nice work John!

...or a dishwashing machine arm Thanks Al.

So that I get a handle on these things, or at least a better handle, what it appears is going on with the com timing is that the position of the com tab relates to the TWO poles the coil is wrapped around as a single pole. That being the case, the timing would be heavily advanced towards clockwise rotation. That would account for the way the motors I wound seem to prefer to run, but the stock Kentron didn't seem to favor one direction as much as the ones I rewound. If anyone here is into the theorey and details of these arms, I would appreciate any information regarding com timing. I may have a whack at even a 7 pole if that ever comes up and someone has a motor that they're willing to experiment with with no guarantees (Don???)

-john

[don.siegel]

Have I got an arm for you!

Don

[havlicek]

Okey dokey Don. If you need my contact info again, just shoot me a PM. This will no doubt be a real adventure

-john

[Alchemist]

HI John,

Very unique armatures!

I have been meaning to ask what is the process for balancing an arm please? I'm aware you put the arm on razor blades and then you drill balancing holes/marks. But how do you determine why/where and how deep to drill please?

Thank you for your time.

Ernie

[don.siegel]

Okey dokey Don. If you need my contact info again, just shoot me a PM. This will no doubt be a real adventure

-john

Will do John: do you want just the arm, a complete motor, or various parts - or a different combination of all of the above?

Don

[havlicek]

Will do John: do you want just the arm, a complete motor, or various parts - or a different combination of all of the above?

Hi Don,

Just the arm is fine as long as it's still intact. I'll need to look at it for a while to try and figure out what's going on before I strip it and ruin...er...rewind it. Besides, I have a feeling that the motor that goes along with such an arm would weigh 5 or 6 lbs and the shipping fees would be prohibitive I'll just take some measurements of the arm and note the position of the com beforehand so I have a snowball's-chance-in-you-know-where of putting it all together correctly afterwards. Then I can feel good that when I send it back to you, it will at least fit in the motor.

But how do you determine why/where and how deep to drill please?

Hi Ernie,

For me, the position of the holes in the horizontal plane is simple, I try and get the holes centered on the poles since that's where the most metal is. That allows me to drill with less fear of going too deep and either weakening the stack (been there done that) or hitting the coil (been there also...I think it was the same trip)...or both. In the vertical plane, I just start at the top of the stack and work my way down as necessary. With static balancing, you don't get visual "feedback" precise enough to really know if the arm can use weight-reduction in a precise spot on the pole other than just a particular pole. So the object is really just to improve the arm and hope that the improvement is significant...sometimes I get pretty lucky in that regard.

As for the depth, that's a tough one. The inner profile of different arms (web) can be VERY different...so the width and depth of the balancing holes can vary a lot and still be "safe". I try and look carefully at the arm before I wind it and use that to determone how I'll later drill it, but it's all guess work. I suppose I've gotten a smidge better at that part of all this, because I haven't ruined an arm in a while. I still keep coming back to the truth though that the greatest imbalance seems to come from shaft problems, even with drill blanks. Of course, the worst problems are most often with the soft shafts. Some of those you can actually bend easily with your fingers...at least if you're a carpenter (as I know you are!).

-john

[HarV Wallbanger III]

Wow beautiful John!
Hey I have 5- 7 pole arms for you to wind now!

[Alchemist]

Hi John,

Thank you for the explanation. After you have "machined/drilled" the balancing marks, do you place the arm back onto the blades to see if it still has the "lop-sided" tendency; or, as in music, "syncopation"? I'm not sure what term to use, so please pardon me.

Thank you John!

Ernie

[68Caddy]

John you know that I will post on this sooner or later about building motors, I could not use any thing of this build ups due to the fact that what I race is a spec motor.
SO what do you guys do with all this great motors of yours, and what type of racing do you guys do? Or is this just what you can do with a hot set up of motors?
92 pages of cool motors to race and to blow up but what classes do you race it with?
I love hot motors but where and what class can I use the motors you build?
Or is this a post's just about how much fun it is to rewind motors and set the gap on magnets ..... then its all good but I wish I could use this little monsters on the track to burn some rubber of the wheel.



Nesta

[havlicek]

Hi John,

Thank you for the explanation. After you have "machined/drilled" the balancing marks, do you place the arm back onto the blades to see if it still has the "lop-sided" tendency; or, as in music, "syncopation"? I'm not sure what term to use, so please pardon me.

Thank you John!

Hi Ernie,

Yes, you keep drilling a little and then putting the arm back on the blades to check where the weight is and do that until there's no obvious "heavy" pole.

John you know that I will post on this sooner or later about building motors, I could not use any thing of this build ups due to the fact that what I race is a spec motor.
SO what do you guys do with all this great motors of yours, and what type of racing do you guys do? Or is this just what you can do with a hot set up of motors?
92 pages of cool motors to race and to blow up but what classes do you race it with?
I love hot motors but where and what class can I use the motors you build?
Or is this a post's just about how much fun it is to rewind motors and set the gap on magnets ..... then its all good but I wish I could use this little monsters on the track to burn some rubber of the wheel.

They can be used in the same racing class as those that use Rick T's chassis Nesta. Then again, you'd have to ask Jeff Buyer what classes he runs his Kemtrons in, or Maximo what classes he runs all those beautiful motors of his in, or Joe Lupo what classes he runs all those amazing vintage cars of his in, or Don Siegel what classses he runs his cars in, or Jairus what classes people race his amazing builds in, or Dennis Sampson, John Dillworth etc. etc. etc. After all I don't build cars for people and only do motors for a small number of slotters. Before there were "spec" motors (ie...throwaways), people had to learn to rewind or at least to build motors as well as chassis. I'm trying to help those who still want to do that...keep the craft alive, and have done it all for break even only a few times, but almost always at a loss and even many times for free with my parts. I also just like slot cars and this site, doing my small part to participate and support both. By now (as you said...92 pages) and after having said so countless times, I'm puzzled you could ask....unless you really already knew all that

Hey I have 5- 7 pole arms for you to wind now!

Thanks Barney!

-john

[Kim Lander]

Nesta,
You can do what I do with my HONDO-ROCKETS....put them in a chassi and enjoy and amaze others when they find out what you are running, then put them on whatever you display what I call "History Cars"....I put them on a shelf and let anyone look at them , the motors "not" in a chassi is what catches the eyes of people then the cars. I still love to rewind but love showing off my stable of Johns motors even more. Nuff said I guess.....just my opinion of what to do with these beasty motors....................Kim