low turn motors (or BL) that are 4s capable

[ultimate_monkey]

like it says, im looking for some lower turn motors 15-19t for my scaled that i can toss in when i wanna really bash it, but they need to be 4s capable, im sure i can get most to work if i gear it super low but wheres the fun in that.

im running a ballistic crawler bl 18.5 t for crawlin, and would like somthing about 2x the speed.

iv burnt up a few cheaper motors real quick, so can any one make some recomendations?

srry for the quick undetailed post, im on a boat headed to work typing on my smellular

[JuziTin]

try getting the castle creations 4600kv motor. 4s capable, but requires BL and 4s capable esc. i would recommend the Mamba Max Pro with CC4600 Motor combo. you would have to gear down SO MUCH THAT it'll be redicoulous. your best bet is to go with theTraxxas VXL motor. and use 2s. its good for gearing up for speed, and gearing down for torque. it is not 4s capable though. it is only 3s capable.

[Blood_Clod]

Maybe go to harbor freight and buy this Bad to the Bone 18v drill: http://www.harborfreight.com/power-t...kit-91396.html $18.99

I think those have a 550 can size and a bit longer than standard motors, so it might take some massaging to mount. I would assume it's a lower turn motor like maybe 12-27turn...?

Other than that you could go brushless, but you know what you need in that department...

FYI, the CC 4600 is not 4s capable.

Input Voltage 12 NiCad/NiMh MAX
3s LiPo MAX

[JuziTin]

BTW, the new ROAR legal one is. the old is not.

EDIT: nevermind, i was pretty sure it was though. but apparently its not. thnx for clearing that up!

[JohnRobHolmes]

The 18.5 motor should take 4s. I know a 21.5 will.

[EddieO]

Any brushed motor will in theory take it....

Be aware though, as you increase voltage, your torque is gonna go down.....add in the fact, as you go down winds, the motor inherently will make less torque.

That being said, I have TONS of 7-19t arms I am clearing out for $5 bucks a pop....PM if you want some...they will fit in any modified can no problem....

Later EddieO

[JohnRobHolmes]

Why would torque go down as you increase voltage? Amps create torque, voltage increases amps if the load is there.

[EddieO]

As you increase voltage, you will oversaturate the arms magnetic field, the moment it eclipses the magnets, torque will go down....

RC drag Racers would have this problem when they used ferrite magnet motors, hence why they all went to Cobalt or NEO mag motors.....and even then, it would still happen with too much voltage......

You can search Big Jims forums on rccars.com and you will see him say it multiple times.....

The question is really, at what point does it happen in our brushed motors.....I do know a lower wind like a 7 turn it will happen a lot sooner than a 55 turn...

Later EddieO

[JohnRobHolmes]

Right. Saturation does happen, but you can't just say that voltage decreases torque. Marginal torque only decreases after saturation.

[EddieO]

Thats the problem, we really don't know when.....it could be before saturation, at least that's the way Big Jim explained it to me....

I am gonna test on it....see what I can figure out.....

Pull out some old dyno sheets if I can find them....

Later EddieO

[JohnRobHolmes]

Temperature has a big effect on magnetic strength too, so really we are working with saturation and second order effects. What we could find out is where the torque drops off. Each wind will show a different amperage for this, but a certain motor construction will be very consistent where the torque slope changes.

Here is a sample of such testing. As you can see the slope of torque changes at a particular value, but until that point the slope is linear. Since the torque does not plateau we can assume that it is not magnet saturation, but another effect that is causing the change.

[indiana mudcat]

Just buy a 12.3mm rotor, your wheelspeed will almost double, 1650KV vs 2700KV same motor, the 13mm rotor will break the difference.

[ultimate_monkey]

thanks for the input guys it seems that i am on the right track, but i was only asking since it seems im burning up motors real quick and im not sure why, nothing binds, nothing gets hot to the touch hell i cooked my 18.5t ballistic today and it wasnt even warm , i shot it with my heat gun and it was cooler then the ambiant out side tempiture,

the only reason im looking for something 4s capable is my 2 and 3s lipos are only 1000mah, and well 5 min of crawling isnt worth the drive i need to make to go any whgere, my 4s are both 2250mah

i figure im just far to awesome for this kinda junk so my motors get sad and quit on me, guess im gonna stock up on some magnetic wire and just carry around afew spare motors when i go out lol