70 replies to this topic

[havlicek]

I had the lams for this laying around, and figured I should do something with them.  By actually doing it again, I now remember why I don't do them until after it's been so long that I forgot why I don't do them.    The lams are from a motor manufacturer in China that does train motors, and are originally assembled in an extreme skewed manner...so, undoing all that becomes necessary.  Here, the shaft was no bueno, and that makes re-shafting necessary.  On top of that, the 5 pole coms I have, are for the larger FT36D shaft, which means sleeveing the inside of the com bore, a difficult thing in itself.  *You can't be sure of how well a sleeved com has come out until after you try cutting it.  Here, it only took a couple of light cuts...whew!  After all that, I could finally space, wind, epoxy the arm...torture.  I did 34 turns of #29 awg per pole, which should be (*according to my non-existent meticulous notes) a nice wind, not particularly hot...but very nice.  

The arm is just over .560", which happens to be very nice for a regular-old Parma D motor with the very sturdy EPX magnets.

[Geary Carrier]

Now this is down in the trenches and grinding it out...  

[Jaeger Team]

A real nightmare passed in the best way...

[SlotStox#53]

A sequentially wound thing of beauty looks great John!

[Mark Johnson]

I want a 5 pole pitman wound like that !!!!!!

[havlicek]

Hi guys, and thanks!  These things are a real PITA in so many ways, I won't be doing another for a long time.  I don't have the resources to really flesh-out all the possibilities with them, so they are more of a "collector" kind of oddity than anything.  They tend to run very smooth and use relatively little current...but it's hard to compare current usage with a three pole, because the winds are completely different, even when winding them this way.  ***I settled on a ballpark by adding-up the total number of turns I might wind on a three pole, then dividing that by five to come to a starting point for a five pole wound this way.

Sooo, an "average" or "usual" wind on a three pole #29 wind would be something like 50 turns.  That makes 150 turns total.  Divide that by five, and you get 30-ish turns on a five pole.  Here, I went a little beyond that and did 34 turns, and kept the timing advance very low at around 5 degrees...just to be safe    I know I know, it may sound stupid, but I had no other way to figure these things because no one I'm aware of wound these this way.    I had done a couple as hot as #27 wire, probably around 23 turns or so, and those ran pretty danged fast.  This one should be a little safer, and probably even good on higher voltages.

For the setup, I'll use the small brush (FT16D size)  Mura hardware mounted on the Parma end bell since I have a set with the tabs still on there.  I've done these before using large (36D) "modern standard" brushes, but even with these coms being fatter than the norm, the segments wind up fairly small.  I figure the smaller brushes are a better bet.

[Dave Crevie]

What are you smoking, man? When I was doing magwinder drag cars, I did a lot of big Pittmans and Rams with five-pole

arms. I even tried a few double and even triple winds. Anything to win! 

[havlicek]

What are you smoking, man? 

 

Nothing illegal, I assure you! (* I prefer bourbon straight up, or a nice VSOP)

[Dave Crevie]

I love that you are not afraid to attack a project. Maybe I will rewind some of my old "smoked" big drag motors. They will

most likely be run on 12 volts rather than 36 now, so I will have to decide on a wind. And they probably will never break

a second again. But I still want the cars to be fast.

[havlicek]

...and here's the setup for the arm:

[Dave Crevie]

Awaiting the results with baited breath. Do you have a tach to check RPM? 

[havlicek]

Awaiting the results with baited breath. Do you have a tach to check RPM? 

 

Hi Dave,

     The arm will need to go out for grind/balance before spinning it up.  I have no need for a tach anyway though, because I already know *about how it will run and the only test that matters to me is the one that happens after it's installed in a car and on the track.    I've done maybe a dozen or so of these things using my rough "equation" above, and performance seems to pretty much hold.  So this motor should run something like an average three pole 50/29...but different. 

[Alchemist]

I really like that "hue" of green John!

 

It's appropriately "festive" this time of year - LOL!

 

Very unique as usual.

 

Had you left the armature lams in the skewed position,  would it of made a difference (smoother) in performance?

 

Thanks for sharing John!

 

Ernie

[havlicek]

Hi Ernie

 

 

 

Had you left the armature lams in the skewed position,  would it of made a difference (smoother) in performance?

This could take a while...so hang in there.    Skewed-lam armatures tend to soften the response of the motor, and they cut way down on "cog".  I like them, but I think they work better for slots with 3-pole lams that have typically narrower crowns (*wider gaps between poles).  The model train application for DC motors is way different from slots.  There, what's needed is the smoothest power delivery from zero RPMs (stop) up, and from running speed back down to stop.  The last thing you'd want there is a train that jumped and burned rubber...or...metal.    So it's smooth power delivery, torque and low RPMs.

With slots it's possible to have too much instant torque and RPMs with the hot three poles we run.  Some call it the "lightswitch effect", where the car becomes hard to drive, and people will try to regulate that using the special controllers and chokes available today.  Skewed-lam three pole armatures can be wound hot and still make for a somewhat softer torque curve, but still have the top end.

Five pole armatures, when skip-wound (*the "normal way), most often have a boatload of thinner gauge wire on there.  You would think that all that iron in the 5 pole lams wouldn't leave enough room for a lot of wire, but skip-winding makes that possible since the coils are much larger than the size of the poles.  A lot of skinny wire = a lot of torque and lower RPMs, and the five poles means very little cog.  These motors, can also do OK with higher voltages, which may be why the drag guys still use them, and be able to produce higher RPMs.

Five pole skewed-lam armatures take all this even further away from the "ideal" for slot cars, and I don't think (*although it's impossible to remember for sure after doing so many armatures and motors) I've ever done one for slots for that reason.  Besides, these things are hard enough to wind as-is.

***So, winding a five pole for slots the same way (*sequentially, one pole at a time) as you would a three pole makes for a "different" kind of performance.  It ups the RPMs from what you'd expect for a five pole, smooths out the torque curve and seems to make for an efficient, cooler running motor.  These things are really curiosities, because the investment in time, money, tooling to try and make the best five pole armatures for modern slot cars is way beyond what anyone in their right mind would spend.  That's even more true because there's no way of knowing whether that investment would ultimately even be "worth it". 

[Phil Smith]

John, it seems you had to skip a com segment when connecting each pole. I.E., a pole is connected to com sections 1 and 4, the next pole to 2 and 5, then 3 and 1, 4 and 2, then 5 and 3.

 

And then I hit my mouse with my arm and that somehow erased the rest of a long post I had written. @#$%!

[havlicek]

 

 

And then I hit my mouse with my arm and that somehow erased the rest of a long post I had written. @#$%!

 

I hate when that happens (*every day).    There's also a thing here at SlotBlog, where I type stuff and see a correction I need to make.  I go back to the sentence or place and start typing, but part of the new typing winds up at the end of the paragraph.  Weird, and it means I actually have to watch what I'm doing.  I hate that too!

[Alchemist]

Hi John,

 

Thank you so much for taking the the time to answer my inquiry!

 

By the way, have you done any "skewed" 3-pole motors?

 

I don't recall if you had in the past.

 

Thank you again John!

 

Ernie

[havlicek]

 

 

By the way, have you done any "skewed" 3-pole motors?

 

Many.

[Dave Crevie]

I think John has done everything. I used to take skewed arms and straighten them out. For slot racing you don't need the

skewing, which is done to lessen the "cog" effect, like you do for model railroading. Nor do you really need 5, 7 or even

9 pole arms. Those are for very low RPM performance. We ran those motors geared with very (numerically) low gear ratios,

2 - 1 or less. When set screw wheels came out, we even mounted those directly on the 1/8th inch arm shafts of the big

padlock motors. With good magnets and the right wind, they made good drag cars set up that way. 

[havlicek]

 

 

I think John has done everything.

 

Well...not everything Dave.  I had thought about doing a "star wind", but then figured I'd wait and let someone ask for it, to let them do the experimenting on their dime.    From what I've read, they didn't work all that well.

 

 

For slot racing you don't need the

skewing, which is done to lessen the "cog" effect, like you do for model railroading.

 

Not so fast there Kimosabe   On hotter winds, the skewed-lam stack can make for a more "driveable" motor; a motor with softer torque curve that makes choking the motor down less or unnecessary.  Barney Poynor (*I think it was Barney) posted something years ago here about running a Greenaway-armed motor with a skewed-lam arm that he was stoked about.  His take was that the car ran great (*like a freight train), accelerating along the entire straight, amd was very "drive-able" through the rest of the track.  After winding many of these, I believe that they are worth a look for everything from #27 through #24 winds, and that they never gained traction with slotters *might* be partly due to their being a pain in the keister to build and wind.  It sometimes can pay to go back and look at what the racers from the 1960's and 1970's were trying, because things were more "open" then.

 

[Dave Crevie]

I am thinking star, or what we called a progressive, wind works best with more poles. Field bleed-over from pole to pole

has less effect. If I understand what you mean as a "star" wind.

 

That softness that you get from skewed lams is what makes train motors so smooth. And it will certainly mean the

motor will be less "punchy" in a slot car. Not a bad thing for us dinosaurs.  

[havlicek]

If I remember correctly (*and that is not at all a certainty, since I never did one), the star wind has one of each pole's wires tied to the com segments, and the rest of them all joined together in a pigtail...or something weird like that.

 

 

That softness that you get from skewed lams is what makes train motors so smooth. And it will certainly mean the

motor will be less "punchy" in a slot car. Not a bad thing for us dinosaurs.  

 

To be sure, but it's not really a noticeably soft thing like a train motor.  With no load, the motors just sound and feel...er..."smooth", but still spin-up and down fast.  I think the optimum for these might be a hot #25 wind.  Then, a person who can mess with gears and the actual rest of the car (chassis, body etc.) could figure out the way to get the most out of it.

[SlotStox#53]

When set screw wheels came out, we even mounted those directly on the 1/8th inch arm shafts of the big
padlock motors. With good magnets and the right wind, they made good drag cars set up that way. 

Having done this with medium results, can you remember the kind of wire/wind you had results with? It's such a cool idea mounting the wheels on the arm, who needs gears

[Dave Crevie]

John; Your discription of "star wind" is probably correct. When I was doing big Pittmans in the early sixties, I tried progressive 

winds on a couple of motors. Winding two poles together should have cut down on the poles fighting each other as they passed

the "center" of the magnetic field, causing those poles that were energized to pull harder. Anyway, it didn't work the way I wanted.

 

The last several Ram 857s I did were double winds of #24, and triple winds of #30. I don't remember the number of turns, but I

should still have the "logbook" I used back then. I just need to find it. These were 36 volt motors.

[SlotStox#53]

Cool! Thanks for the info

Would be neat to see your logbook data for the big locks. Have a 7 pole RAM arm waiting for some wire, just gotta work out how best to do the comm connections.

The strip we run our vintage drag proxy has a max of 30volts available so we could get close!