Strange Hybrid of Sorts

[sherifx]

On a whim I decided to take a Stage 1 armature, spinbrush can with magnets, Xmod endbell and put them togeather, but the different thing about this setup is the windings. I wraped the wire 28 turns. I also used a thicker gauge wire, for top end power. All I can say is wow, I'm only breaking in the motor and the thing really creates some power, especially on the top end. One main concern I have is how hot the thing gets. After 5min at 1/2 throttle, the thing was incredibly hot. Not excessive, but surprisingly so, enough for me to mention it. Any explanations as to why? Also, with such a low turn #, do you think I'll run in to problems with current draw and risk burninating my esc etc? Thanks for your input!

sherif

[neurokinetik]

With that few turns, you will almost certainly burn your ESC. The PN Racing S03 runs 37 turns or so, and it requires a FET upgrade or turbo on the Mini-Z.

You will probably find, like I did with my 25 turn motor, that though the motor seems incredibly fast on the bench with no load, that it doesn't have enough torque to be useful in a car.

[sherifx]

yeah I saw exactly what you were talking about. I just thew it in my skyline (awd) to test and it most definetly was useless. I see in your windings findings thread that you mentioned the Stage 2's are 49 turns, while the S03 is 37 turns but requires a turbo or fet upgrade. This leaves me to question where is the middle ground of low turns w/o needing a new ESC? Will the turns vary based on the gauge of wire you use? Thanks alot man


sherif

[sherifx]

I just thought of something. What about going with higher windings, say like up to 60, but using 22 or 26 gauge wire. Wouldn't that produce alot of torque at high(er) rpms? Thanks again!

sherif

[neurokinetik]

Maybe if you are winding a 540 armature, but there is no way you are getting that much wire on a 130 armature. I doubt you could even fit 60 turns of 28 ga, though I could be wrong.

I noticed when looking online for magnet wire just how much difference the guage makes in terms of the length and thickness of the wire. They generally sell magnet wire by the lb, and not by length. For example, a pound of 28ga gives you 1989 feet, while 30ga gives you over 3000 feet, and 32ga gives almost 5000 feet!

I've got two spools of wire coming (28ga and 30ga) so I'll be doing plenty of experimenting in the coming weeks.

As for what is safe on the FETs, the only way to get an idea is to measure the current draw of the motor. Remember that we still don't know the specs on the stock FETs. When I get a chance, I will connect up various motors directly to a set of batteries and start measuring current draw. That'll give us an idea of where the stock motors fall, and what will be OK for the FETs. I could probably even include NML's Stage 10 motor in the chart, as one of my friends has one.

[cyrc]

i dont know about winding motors but could you just cut the same amout of wire frome each thing

[neurokinetik]

Originally posted by cyrc
i dont know about winding motors but could you just cut the same amout of wire frome each thing

Yep. That certainly does work. It's even better with the timing advance...

[sherifx]

What is cyrc suggesting?

sherif

[neurokinetik]

Instead of totally rewinding the motor, try this:

Looking at the top of the armature with the commutator facing toward you (like this pic)



Cut the wire to the left of each commutator contact. Unwind about 5 turns from each pole, then resolder the loose end back onto the contact. Try it with a stage 2, for example, changing it from the stock 49 turns to 44. It makes a big difference.

[sherifx]

Cool, thanks!

Now we've been discussing current draw and all that, so I picked up a multimeter to get an idea of whats going on, and I tested a stage2 motor & then my 28T motor and the stage2, peaked at about 5Volts while the 28T motor peaked at about 4.85Volts at full throttle. Now I tested the current coming from the ESC itself, and that was coming out at a max of about 5.35Volts at full throttle. Maybe I'm approaching this the wrong way, but that doesn't seem to make sense.

Hopefully you can enlighten me as to whats going on.

is it possible that the current draw from the stage2 is ~0.35volts, where as the 28T is ~0.60volts. Anyways, I really shoulda taken some classes stuff .


thanks
sherif

[arch2b]

Originally posted by neurokinetik
Maybe if you are winding a 540 armature, but there is no way you are getting that much wire on a 130 armature. I doubt you could even fit 60 turns of 28 ga, though I could be wrong........

i look forward to your findings. you've posted some very informative motor information.
my experiences are limited to replacing magnets and brushes but i'd like to find a way to increase the speed of my monster a-bb motor with drac's neo magnets. i'm assuming this can only be done by finding the perfect number of winds.

btw, have you seen atomics new end bell caps? i have an atomic modifed motor and the new end caps are very nice. they fit much better than audley's in my mini-z's.

i just got an xmod last night but haven't had time to touch it but i have several motors i would like to test such as;
mini-zracer a-bb
mini-zracer o-bb
atomic modifed motor
pn speedy
pn s01
chaser rc m'z stock motor
chaser rc m'z modified motor

i though i had read the xmods can handle more current draw than the mini-z's is this so or will i have to mod it to handle some of these motors?

[TypeZer0]

sherif, what you measured is voltage. current is measured in amps and milliamps.

normally (according to my physics and circuits classes) the ammeter should be placed between the esc and the motor in the circuit so that it's in series. this will tell you the current being drawn from the esc. my radioshack $19.99 digital multimeter, which can't handle more than 200mA, will only measure current when it's in parallel with the element. i guess it depends on what multimeter you have, i jsut found it odd that my multimeter behaved like that. so bascially, i would measure current the same way you would measure current, touch the leads on the two motor contacts. it's much easier this way than trying to wire my multimeter in series but it just goes against what i learned in class. heck, the ammeters in my labs required it to be wired in series. oh well, makes it easier for me. but now i need a multimeter with a wee bit higher range.

*Edit*
sorry for rambling on like that lol

[neurokinetik]

Mine can handle 20A... I just need to wire it in series to do my testing.

As TypeZero mentioned, you generally have to break the circuit and put the ammeter in series in order to use it. It's a pain, unless you either have a clamp-on ammeter (which really only works with AC, not DC) or you have the ESC out of the car already so that you can disconnect one of the wires to wire in the ammeter. (Which I have, since I have a spare car)

[sherifx]

If I'm not mistaken, you can convert Volts in to Amps here -> http://www.onlineconversion.com/electric_current.htm

I see what you guys are talking about in regards to metering system. I too have a $20 Rat shack meter and can only test the system at the motor (where I took my above measurements from). So what are we supposed to do now ?!


sherif

[neurokinetik]

Originally posted by sherifx
If I'm not mistaken, you can convert Volts in to Amps here -> http://www.onlineconversion.com/electric_current.htm

sherif

:lol: That doesn't work... without knowing the impedance of the motor, you can't calculate current from voltage. It's called Ohm's Law.