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JeremyC
2010.01.03, 09:15 PM
I acquired a spare Atomic Standard BB motor to attempt a hand-wound project motor. I unwound the Standard BB and found that it was a 50 turn motor, for anyone wondering.

I am going to rewind it, and am trying to figure out how many turns I should put on. I'm thinking either 40 or 45 turns, but am trying to get an idea of how much a change that will make. Please anyone chime in.

blt456
2010.01.03, 10:45 PM
Uh it depends what you want it for...5 turns makes a lot of difference esp. with the added torque. Also a tip: don't solder the bare wire the the comm tabs to reduce weight..5 turns can be seen with the same gear ratio but I think different ratios will make a bigger difference as far as stock motors (generally 50t+). For motors under 40t, you can start to see how just 2 or 3 winds affects the motor's performance...

JeremyC
2010.01.03, 11:29 PM
Uh it depends what you want it for...5 turns makes a lot of difference esp. with the added torque. Also a tip: don't solder the bare wire the the comm tabs to reduce weight..5 turns can be seen with the same gear ratio but I think different ratios will make a bigger difference as far as stock motors (generally 50t+). For motors under 40t, you can start to see how just 2 or 3 winds affects the motor's performance...

Luke,

Thanks for the thoughts.

So, are you suggesting that I try 45 turns rather than 40? My goal is to build a motor that is slightly quicker than the Standard BB; something about as fast as the Stock yellow label.

I'm not sure what you mean by "5 turns can be seen with the same gear ratio"; do you mean that I'll need to change gear ratio to feel the difference?

-Jer

blt456
2010.01.04, 12:22 AM
What I meant was that close results with stock motors I think gear ratios play a bigger role than 5 turns... I have never driven a atm yellow stock motor so I cannot say. Less turns = more rpm

JeremyC
2010.01.04, 09:22 AM
What I meant was that close results with stock motors I think gear ratios play a bigger role than 5 turns... I have never driven a atm yellow stock motor so I cannot say. Less turns = more rpm

Ah.. Ok.

The Yellow label seems to have more torque, and slightly more RPM. Essentially it accelerates faster and seems to end up with a higher top speed on a 25 foot straight. (NYRC) I generally run 44/10 for a final drive ratio of 4.4, if I could get a bit more RPM I might be able to swing a 44/9 at 4.9. This might get me more acceleration due to the gear change, and possibly more on the top end.

With the Standard BB 44/9 seems much too slow on a big track, but I'll run it on small tracks. 44/8 always seems too slow...

If it doesn't work, well, at least I tried to build a motor. :P

blt456
2010.01.04, 11:45 AM
Have you tried the PN 64p gears? The spurs last forever and I think you will gain a lot from your car...I ask since you are talking about stock gear ratios

JeremyC
2010.01.04, 12:17 PM
Have you tried the PN 64p gears? The spurs last forever and I think you will gain a lot from your car...I ask since you are talking about stock gear ratios

I had 64p on my car for a bit, and it was nice to have a finer grain control of gear ratio. I'm planning on going to 64p when my spur/pinion is worn.

I'm not convinced that there 64p is any more efficient than 48p though. Assuming your spur is true 48p. Back in the days of the gear diff with whatever strange teeth on it wear was a major problem. But with 48p gears on both spur and pinion I think the wear is comparable to 64p. The biggest benefit of 64p is the ability to change ratio in smaller increments.

rocketman
2010.01.05, 04:47 PM
I would say that my experience with 64p at this scale that the differences are less noticeable than with larger scales but still present. Mechanically there are more teeth to propel you forward and there is a finer gear mesh, therefore less backlash, meaning higher speed and mechanically more acceleration. But for me, you point out the real difference I find at this scale and that is the finer adjustment in ration allowing a more precise tune of rollout making the car easier to operate. I also like Reflex Racing Spurs and while some have had issues with them, I think they are the best made for speed and I like their durability. JM2C but the gear stuff probably should be for another thread

Felix2010
2010.01.05, 05:28 PM
Jeremy, the thing about rewinding a machine-made motor like the Atomic Standard for example, is that the gauge or thickness of the wire used is thinner(higher#) the higher the winds the motor has. So a 50t Atomic Standard motor shouldn't have the same thickness gauge wire as say an Atomic T2, which is around 35t I think. When you remove some wire/winds from a 50t motor, the armature actually will lose some of its power because the wire isn't large enough to handle the current that would make it a faster motor. I am not good at explaining things, so I hope you can understand what I mean. :o

Basically, you can reduce the # turns an armature has, but I would not reduce beyond 5 turns of the original.

Hope this helps:)

JeremyC
2010.01.05, 06:06 PM
Jeremy, the thing about rewinding a machine-made motor like the Atomic Standard for example, is that the gauge or thickness of the wire used is thinner(higher#) the higher the winds the motor has. So a 50t Atomic Standard motor shouldn't have the same thickness gauge wire as say an Atomic T2, which is around 35t I think. When you remove some wire/winds from a 50t motor, the armature actually will lose some of its power because the wire isn't large enough to handle the current that would make it a faster motor. I am not good at explaining things, so I hope you can understand what I mean. :o

Basically, you can reduce the # turns an armature has, but I would not reduce beyond 5 turns of the original.

Hope this helps:)

I understand what you are saying. If I use a thicker enamel wire would that compensate for it?

-Jer

rocketman
2010.01.05, 10:57 PM
I think this is one of the most interesting issues in RC cars. I am not an EE but have been told by very knowledgeable people that the energy flows generally on the outside part of the wire, so the larger diameter the wire (smaller gauge#) the more energy can flow and therefore the more power could be had. Back in the hayday of 10th and 12th motor winds were becoming more and more of a black art with multiple twists of wire of the same gauge, then there was the multiple twists of different gauge wire, and we went from straight stack armature like we have in mini-z to skewed stacks, like Felix2010 talks about and all kinds weird sorts of stuff. Mini-z is the last of the breed in that it uses technology that is generally not used anymore in other competitive classes and I think that is a good thing because it keeps the costs down. I was looking at a motor a month ago for an 8th scale brushless buggy and it costs 750.00 and I think that didn't include the ESC. So for around 30 bucks you get a nice PN/Atomic motor and if you spend around 50.00 you can buy a really nice custom wound motor or as you wish do some surgery on an old motor and try some winding on your own. Balancing and a trued com is really important, but I am sure you'll enjoy it.

Felix2010
2010.01.06, 03:45 AM
I understand what you are saying. If I use a thicker enamel wire would that compensate for it?

-Jer

Most definitely:D

The thing is, you can only go up a step i gauge, like say from 31gauge to 30 gauge, because you will run into problems fitting the winding on the armature cleanly. My buddy Flashsp-2 (Ouch, my foot!.... dropping names:D) has done sick patterns and I believe he fit a 43t single-patern-wind using 28-29gauge on an Auldey armature. Again, all manufacturers use parts that I don't know what brand/manufacturer they use, and this comes into play also. You mainly need to see what works by trial & error. But what I've said is basically a good ballpark estimate to start.

Also, if you are just winding the arm with no consideration to the pattern, you might be able to fit a few more winds on the arm (Just look at the PN 38t machine-wound arms, they use wicked-thick gauge and are stuffed to the max). But then again, a good pattern usually makes better use of available arm space. Now that I think about it some, You could start with a pattern-wind, then fill up the rest of the open space using any available space there is for max winds/armature.

Felix2010
2010.01.06, 03:47 AM
Iím new here and in fact this is my first post; so here goes..Do you guys know what the gauge of wire that PN 70 turn stock motor has and what the PN 07 BB stock motor has?

Thin and less-thin, respectively:D I'd guess 31-33 gauge for the 70t, and maybe 30/31 for the 50t.... Just a guess though.

mk2kompressor
2010.01.06, 05:26 AM
also a pattern wound has more or less equal lengths of wire on each pole,making the motor more efficient;)

MINI-D
2010.01.06, 09:20 PM
Hi Jeremy,

this is old info. but GREAT info. :D hope it helps :)

http://www.slotmonsters.com/simco-slot-car-armature-rewinding-instructions.ashx

http://www.ncphobbies.com/rewind.html

http://www.freewebs.com/slotcarbuilder/page5.htm

D