3573 replies to this topic

[Victor Poulin]

Ernie,
Measuring air gap is just using simple mathamatics. Hole size , minus arm dia , divided by 2 = air gap

Lets say you have a 530 hole, and you install a 518dia arm, that will give you a .006 air gap.
18 from 30= 12 then divide by 2, and that gives you your .006

[havlicek]

Hi Vic,

I don't know what the stock springs are like, but if you have anything heavier I would definitely try them and monitor changes in performance. Next time I play with those Emovendos...I think I'm going to start with a big hole and then shim if it seems like a good idea. If they weren't so strong, .525" would be nice and tight...but I'm thinking there's just too much there for all but a flat out open wind. Crazy stuff!

That came out the nuts John !! I wanted to ask you how you dye your endbells?

Thanks Vic...this one really came out sweet and it would be great to see it wind up in a "period" type car or Thingie. I dye the endbells with fabric dye like "Rit". It works well as is durable when done...plus it adds that little je ne sais quoi. Plus, with all the original parts (except for the arm blank which is the visual and functional equivalent of a short stack Mabuchi), it's all pretty much what could well have been done back then.

-john

[Victor Poulin]

John,
So your thinking maybe I went to tight with my gap for the strength of these mags?

Vic

[GearBear]

Vic,

Remember that a GP27 and a GP20 are the same wind. The only difference is the GP20 has to be .513 in diameter and the GP27 is often much smaller in diameter. I've got one from the early '80's that is .459" in diameter and I recently purchased one in a .490" diameter.

I would try Camen Regular springs on that puppy. I'm sure they will do the job! We use them in our Eurosport/Cobalt motors.

In our Cobalt motors, we typically run a .480" arm in a .490" hole. On my C-Can Group 12 motor I'm running a .540" diam arm in a .565" hole. So it all depends on how you decide to set things up. I built a TOP Gun C-Can drag motor with a .513" diameter GP20 arm with a .520" hole. It had BB's on both ends, some quad magnets, and shunt wires. That motor screamed!

[Alchemist]

Ernie,
Measuring air gap is just using simple mathamatics. Hole size , minus arm dia , divided by 2 = air gap

Lets say you have a 530 hole, and you install a 518dia arm, that will give you a .006 air gap.
18 from 30= 12 then divide by 2, and that gives you your .006

Thank you very much Vic - I appreciate it!!

Ernie

[havlicek]

John,
So your thinking maybe I went to tight with my gap for the strength of these mags?

Vic

Hi Vic,

Could be is all. The motor I built using these magnets that worked fine is a #25 and I think a #24 might even be better??? We're dealing with a lot of variables in a case like this:

-airgap
-can type
-wind (I don't think so with a #28, but...??)
-magnet field strength relative to the field strength generated by the arm coils
-brush springs...often (but not always) stronger springs will result in more power produced (watts) and more power used (current draw)
-available current (the motor may need shunts if it's starved for current)

...and those are just the bigger issues. Things like the type of brushes, the accuracy of the setup, the condition of the com, arm timing and stuff I'm not thinking about can play a role here. The guys who have more experience with setting up race motors might even be able to make suggestions by just reading all this.

-john

[Victor Poulin]

Thanks John,
I think along with trying a diffetent set of springs, I,ll also try shunts. I figure at this point it can't hurt

Vic

[havlicek]

Hi Vic,

Shunts couldn't hurt, but I would suspect that least of all on that wind. It's always seemed to me that only the "big wire arms" really need them...#26, #25, #24 and...if anyone dares...#23 Because the motor type and the magnets are all unknowns, we're kind of in uncharted waters here...but exploration is fun!

-john

[GearBear]

John,

How many turns of #25 or #24 are you able to use?

I still need to contact Bill and see about getting some arm blanks that can be ground down to .480". I want to wind up a Euro arm and give it a try. I figure I can wind it and braze the wire to the tabs and then send it out for the epoxy, comm cap, and balance. I want to try a 22T24 and a 20T25. If I can get to the point of making my own, I can try different winds a lot cheaper than having to spend over $100 per arm!

[havlicek]

Hi Gary,

How many turns of #25 or #24 are you able to use?

I'm not sure what you mean Gary? If you mean...how much wire can I fit on an arm, forget the old "just squish as much wire on there as you can manage"...that's a load of of you-know-what. If you work at your patterns and get it on there neatly, you can get more wire on about any arm blank than will work well...even the old Mabuchi blanks and those tough Mura thick-web blanks. There are ballpark winds for a given wire size that really haven't changed much and those are all easily do-able.

I want to wind up a Euro arm and give it a try. I figure I can wind it and braze the wire to the tabs and then send it out for the epoxy, comm cap, and balance. I want to try a 22T24 and a 20T25. If I can get to the point of making my own, I can try different winds a lot cheaper than having to spend over $100 per arm!

Absolutely Gary. You can learn to "roll your own" and eventually even make arms that are competitive with what you would buy.

-john

[Victor Poulin]

John,
I wanted to give you an update on the Hawk 27 motor. Here's what I did.
As you know, I thought it should have a little more sack than what it did for everything I did to it. So first, I shunted it and - - no change what so ever !! So then I thought I would try a different set of springs, and tried a set of Koford med springs and - - no change
In a last stich effort, I changed the brushes, still using SBF- II and I tried a new set of Kelly springs that I had kicking around.
This seemed to bring the motor up to where I thought it should be.

Now this motor sounds like a 27 It really winds up !! I let it run at 5volts for about 10mins and it ran well and stayed fairly cool.
The odd thing is that it only pulled 1.9 amps when all was said and done. It has alot of cog, in fact maybe to much but it runs good.
All and all, I'm very happy with it, but I still think I can get equal performance using an X-12 arm in the same set up. However I have to say,, that this was a very fun and challenging build.

Vic

[havlicek]

Hi Vic,

Thanks for posting your results The current draw sounds reasonable and if you could run the thing for 10 minutes @ 5V without it getting unduly warm, that's pretty good too! The springs can certainly make a noticeable difference and it sounds like you lkanded on a good option there with the Kelly's. I still suspect that those magnets would be most happy with a bigger wire arm, but then you're faced with the heat issue...so it's a toss-up. Cool project!

-john

[Alchemist]

Hi Vic,

Sounds like a great motor - any pix please?

Thank you.

Ernie

[Victor Poulin]

Ernie,
Sorry but I deleted the pics from my computer, but I listed the motor on ebay and if you click the link theres a few pics of it on there.

http://cgi.ebay.com/...=STRK:MESELX:IT

Vic

[Champion 507]

Cool stuff you got out there on the bay, Vicster! Good info on the brushes/springs, too.

[MantaRay]

Sounds good Vic.........Are you able to let someone Run it on a King or something similiar

[Victor Poulin]

Cool stuff you got out there on the bay, Vicster! Good info on the brushes/springs, too.

Thanks Doug

[Victor Poulin]

Ray,

No, I really just built it for the heck of it. When I built it, I was thinking more along the lines of a drag motor.Being that I wasn't to to worried about heat being a major factor. As it turned out, after figuring out the right spring+brush combo, it didn't run hot at all.

Vic

[GearBear]

Hi Gary,



I'm not sure what you mean Gary? If you mean...how much wire can I fit on an arm, forget the old "just squish as much wire on there as you can manage"...that's a load of of you-know-what. If you work at your patterns and get it on there neatly, you can get more wire on about any arm blank than will work well...even the old Mabuchi blanks and those tough Mura thick-web blanks. There are ballpark winds for a given wire size that really haven't changed much and those are all easily do-able.



Absolutely Gary. You can learn to "roll your own" and eventually even make arms that are competitive with what you would buy.

-john

Wow, I didn't word that question very well. Sorry about that! What I MEANT to say, is, what is your typical wind when you talk about doing a wind with each of those wire sizes. There can be so much difference between say a 19T #25 and a 23T #25 that it can almost get scary! I was just wondering how many turns you "typically" use for each wire size.

And yes, I WILL wind a few Euro arms. It's just going to take a little bit of time to get the blanks and comms.

[havlicek]

What I MEANT to say, is, what is your typical wind when you talk about doing a wind with each of those wire sizes. There can be so much difference between say a 19T #25 and a 23T #25 that it can almost get scary! I was just wondering how many turns you "typically" use for each wire size.

Hi Gary...gotcha. There is really only a "range" of turns for any wire size because of different factors. For one, the arm blank itself may have a thin or a thick inner "leg" for winding, and the shape of that leg can vary greatly. Many are straight and "end" at an abrupt 90 degree angle where they meet the back of the pole face. Many have a curve at that point as well as either a curve or a "bevel" where they meet the center shaft portion of the laminations. Some have a tapered leg that gets wider as it goes out towards the poles. Some have legs that are thick in profile and some are very thin and even the thickness of the curved outer pole faces varies a lot. This can make a large difference in the length of wire for a certain wind between these even when the number of turns is the same. Then there's also the length of the stack to account for...so imagine the difference in length of wire between a .350" stack and a .460" stack!

Then there's also the track power and the actual motor setup to take into account...as well as driver preference. On an old Mura .007" blank around .440" - .460" long, 21T/#25 awg was a common wind (it's still a great wind)...but some drivers may have preferred 22T/#25. On that same type stack...25-26T/#26 wire works awfully well and is a great compromise between balls to the walls power and a bit longer life. There's also the thickness of the wire's insulation and among regular single build coatings there can be a noticeable difference...let alone the huge difference when you use a double build. You're also doing a balancing act between the wind and the com timing to make things even more complicated! Confused?...me too! Often, I just ask the person what wind they are looking for and if it sounds a little "off" for the arm blank I'll be using, we talk about it a little to decide on a way to go. Specific winds for a wire gauge are not a secret like they may have been in the 60's and spec winds for a group motor are a matter of record...I just ask people what those are since I don't know them by heart. You can take those winds and alter them a little, but they're generally a great place to start. With the big wire open arms...it's a matter of bravery

And yes, I WILL wind a few Euro arms. It's just going to take a little bit of time to get the blanks and comms.

Great! Bill Bugenis has both and they're excellent!

-john

[havlicek]

...speaking of Bill Bugenis, here's a shot from the man-cave of the next batch of Eurosports arms for Bill and Lou Pirro all ready for welding:



-john

[Victor Poulin]

John, I'm drooling

[Don Weaver]

So that's why you haven't posted anything for the last few days!

Don Weaver

[GearBear]

...speaking of Bill Bugenis, here's a shot from the man-cave of the next batch of Eurosports arms for Bill and Lou Pirro all ready for welding:



-john

Let's see, I'll take that one, and oh, gotta have that one. And this one...

Shoot, John, Those all look great!

Did you have to change your method of welding the wires to the comm on the Euro motors? Or are you still using the tungsten electrode with the silver solder paste? Also, have you found that you need to cap the comms on these?

[havlicek]

Thanks guys...as we (Bill, Lou and I) keep developing these things, I'm adjusting a little here and there...but I am falling into a rhythm.

So that's why you haven't posted anything for the last few days!

Nah Don, I did these all last Sunday but figure I should lay back some here and try (at least a little) to tone-down the bandwidth usage

Did you have to change your method of welding the wires to the comm on the Euro motors? Or are you still using the tungsten electrode with the silver solder paste? Also, have you found that you need to cap the comms on these?

Hi Gary,

Not really (I use a carbon electrode made from a C-Cell battery and sometimes a carbon brazing rod cut down), the thing that I had to figure out is that these straight com tabs need a different shaped tip than what I use for "hooked" com tabs. Jeez...tungsten might just work because of it's resistance...but I wouldn't have any idea where you'd even get a piece of tungsten rod. Other than that, I do them pretty much the same. I'm pretty sure Bill has capped the coms on all or at least some of them and he's gotten good mileage out of the arms. His coms are very strong and the segment gaps are nice and tight.

Anyway, before I weld these, I'm going to go over all of them and, if I see any I don't like, I'll dewind and rewind them before welding them. Bill's on a mission to get every little detail right so I want only my best to go back to him. Thanks for looking in guys.

-john

-john