Mod motor question

[johnbull]

Hi friends. Greetings from Malta.

I have been playing with mod motors for years but still get caught out frequently with something I cannot explain. Can anybody help.

We ran 10 x 1 motors in our touring cars last season, and 8 x 1s this season. When assembled the armature always gives a nice strong kick when cranked.

We tried some 7 x 1s recently and again the armature is hard to crank and gives a nice healthy kick.

We also tried a 6 x 2 recently and the armature spins easily when rotated with your fingers. No healthy kick.

I thought it was a can with soft magnets so I assembled 3 or 4 different armatures in the same can. Again, all the singles felt strong. The 6 x 2 felt feeble.

On track this is reflected also. Let off into a corner with any of the singles and it's like you have drag brakes, you almost don't even need to help it with the brakes. Do the same with the 6 x 2 and the car just keeps rolling.

This was also translated into lap times. The 7 x 1 was quickest, much quicker than the 6 x 2.

Can anyone explain?

Oh, by the way all these motors are from the same manufacturer.

Regards

Joe from sunny Malta.

[MattW]

Joe, Although they are from the same manufacture, do you konw if they are wound on the same blank?? This has quite a bearing on this.

I'm just wondering if the 6x2 is wound on a "Torquier" (thicker web) blank. If it is then it would explain what you are seeing.

[DA_cookie_monstA]

Matt, you beat me to it, the construction of the blank will affect greatly the amount of 'kick' it gives, also how close to the magnet it runs affects this too. It can't be due to the windings, as these are only in effect with power going through them. Out of curiosity, does it rev harder than the rest, more RPM?

[johnbull]

Hi friends. Greetings from Malta.

MATT & STEVE> thanks for replies.

Taking the 7 x 1 and the 6 x 2 as examples, both appear to be wound on identical blanks. I have them here in front of me, with my calipers too. The single is obviously wound with thicker wire but the double fills the armature more - obviously. Both armatures are of the same external diameter (22.1mm), and both are hand wound and epoxy balanced in the same way.

I realise that the wire itself should not have anything to do with the "kick". This is why I am so "foxed" by the whole thing.

As far as revs are concerned, both rev over 50,000 at 7 volts - that's free revs, but in the car, on the track, the 7 turn motor is visibly faster....balistic in fact.

Since my previous contribution I have tried another 2 armatures ( a 7 and a 6) both with the same results as before - much more kick with the 7 x 1.

I'm wondering if it is a peculiarity with this particular manufacturer. I've got a load of 12s, singles, doubles, triples. I'll try them all in the same can too and see what happens.

Any more ideas are more than welcome.

Regards

Joe from sunny Malta.

[MattW]

Joe, It's the web thickness that is more relevent. If the 6 fills the arm more, then that further suggests that it might be on the thicker web.

I suspect i may know the manufacture you are using ;) :cool: and i think the vast majority of there motors use the thin 4mm arm (at least they used to), that said i also know that they do some on the 5mm. It can be difficult to see what thickness the web is, sometimes you can get in there and see it, sometimes not.

If this is the case then you are probably running the 6 undergeared. I know i usually work on 2 pinions difference between motors of the same wind with the different arms. i.e 2 pinions higher with the thick web.

[DA_cookie_monstA]

Well John, if the blanks are the same, can is the same, the only thing else that is different is the wire itself, maybe they have used a different style/type of wire that does amplify the magnetic field from the magnets in the can, that can be the only answer, if everything else acts the same. It got to be the wire, the only thing I can think of, is that the wire on the other arms maye have a higher steel content in the wire (can't see it being pure copper, too expensive and soft), and the six, due to it's design uses a different wire with a higher copper content??

Matt, if the six uses a thinner web, then that would give the results, but a thicker web would exagerate the affect of the magnets?? wouldn't it??

[johnbull]

Hi friends. More greetings from Malta.

The motors in question are Corally. We have always used them, almost exclusively.

The only differences I can see are that the 7 x 1, which is their GOLD (high torque) spec motor has black dots on the armature, whereas the 6 x 2 is the SILVER (high speed) spec motor which has black square patches on the armature.

Is this of any help?

I must say Matt, the 6 certainly sounded as though it was running out of steam very early in the straight as you said, whereas with exactly the same gearing the 7 just kept accelerating. So yes it is quite possible that we were undergearing the 6, but all this still does not explain the different feel, the kick on the armatures with 7s and 8s.

Generally speaking motors with a "big kick" seem to work alot better on our track.We have tried the quad magnet Reedy too and it just doesn't seem to have the UUMFFF. Orion Core and V2 motors don't produce a kick either, though their armatures are thinner - more gap between armature and magnets, so there is an explanation.

The plot thickens, doesn't it!

Regards

Joe from sunny Malta.

[MattW]

Joe, I have spent a lot of time playing with the Reedy Base motors (Fantoms). The older "Fury" based motors had the 4mm blank (which is believe is the same one that Corally use most of the time) These have a lot of "Cogging" - the stiff feel when you turn them. These have higher RPM and hence need gearing on the low side. The later Ti based motors use the 5mm blank. These have much less cogging and the magnets feel soft, just as you describe. These motors have more torque, but less RPM, and hence need gearing up a bit. Even assuming you use the 2 different arms in the same can the feel and effect is still the same.

Now, as far as i am aware Corally use the 4mm arm for most of their production motors. I haven't actually bought any of their hot stuff so it's not personal experience, but this is what i am given to understand, I do know that the 12's do use the 4mm arm.

Like i say i'm no expert in their range, but i believe that the difference between Silver and Gold is in the wire guage when comparing like winds, i think the arms are still the same.

The orions are interesting. The older Chrome used a thinner blank where as the Core used the thicker one. However like you say the diameter is different so there is another variation to add into the mix!!

The Quad mags of the Reedy KR kill the cogging and that is why they feel the way they do. They also generally need gearing lower to get the grunt out of the corners.

Personal experience tells me that Above 10 turns (12 etc) and the thinner arm seems to be the way to go. Below 10 and the thicker blank has more grunt and mid range and hence seems better. I am sure there are others out there that will disagree, but this is just what i have found with the assortment of arms that i have had over the last few years.

[johnbull]

Hi Matt.Good morning from Malta.

Thanks for your very interesting and informative reply.

I suppose really Mike Smith needs to be reading this. I'm sure that if anyone knows the answers about Corally motors, he does.

So here's the question Mike, or rather the questions - plural.

Do Corally Gold and Corally Silver motors use the same armature blank?

If they do, is it the 4mm or the 5mm.

If they don't which uses which.

Comments from the many other motor gurus who read these threads are more than welcome.

I'll give Constant a ring in Holland this morning if I get the chance, and see what he has to say.

Regards

Joe from sunny Malta.

[Joost van Leeuwen]

The gold en de silver series are wound on different blanks as one is a revvy arm the other is a torque arm. (Silver = high speed, gold = high torque)

Stay away from the silver arms and get the gold ones.

[johnbull]

The gold en de silver series are wound on different blanks as one is a revvy arm the other is a torque arm. (Silver = high speed, gold = high torque)

Stay away from the silver arms and get the gold ones.

Ok. That's just how I figured it out too.

Now can somebody tell me which is which. Does the thicker stack give more torque and more kick, or vice versa.

We have always preferred to use the GOLD motors. Just find them so much more suitable to our track.

Regards

Joe from sunny Malta.

[MattW]

Joe, It's in my huge post above :cool: However to attempt to summerise

Generally speaking the thicker stack will give more torque, although in the can it will feel like it has the weaker "pull" on the magnets. The thinner stack has more RPM but has the strong pull when rotating in the can. I generally gear the thinner stack 2 pinions lower.

This certainly works for Yokomo arms wound by Fantom.

[Joost van Leeuwen]

Yokomo Arms by Fantom :D :D

They'll kick a V2 in the pants anytime :eek:

[MattW]

Yokomo Arms by Fantom :D :D

They'll kick a V2 in the pants anytime :eek:

LOL, I don't tend to suffer for speed :D :cool:

and i don't think i have ever had, or even seen, a reliability issue with them.