mtc3od

Through my limited testing of racing, maybe 35 weekends total, I have always raced a stock motor, in this case a monster, and then replaced the brushes and cut the commutator after 2 runs. It seems to me that if I run the brushes longer I loose a lot of power even with a cut comm and the brushes are broken in again. Is there anyway to create more power with out going through the brushes such as create more spring tension or lighten the spring. I realize that the harder the springs are the more like a disk break the brushes become. Or is it when the serrations are gone I should gear up for the new found torque. Or should I just buy a brush serrator and not worry about it.????

mafiaracers

iTrader: (22)

You should always replace the brushes after you cut the comm. I don't think that cutting brushes is nearly as good as a new brush. That could be why you're losing power. You may have a new face, but the brush material itself may be shot. Try just replacing the brushes every time you cut the motor and see how that works. Then if you're looking for more speed, just run lighter brushes. However, you should always run a slightly stiffer spring on the posative side, this keeps the efficiency up. Maybe your magnets are going out.....it could be one of many things on why you're losing power.

Thats strange because generally, the smaller the comm gets, the more power you will have. Just do some experimenting.....if push comes to shove, buy a new motor.

mtc3od

Ok,
The motor goes right back to its previous capabilities as I replace the brushes. I am just wondering if I should just keep replacing the brushes after 2 runs or is there still just as much speed in the motor just I have to gear it diff.

mafiaracers

iTrader: (22)

That just means that it is really consistant. as long as it isn't getting slower, then just go about your normal routine and you'll be set. You could definetely try gearing, but if you're keeping pace, then leave a good thing be.

Korey Harbke

iTrader: (13)

Well, actually, the smaller the com gets you will have more brush overlap. That causes to be much less efficient and have much higher operating temps. The brushes and comm with start to wear out faster as well. I recently had a monster stock that was ballistic, and it had a com size of .292. I started using it more then it started to loose it's bottom end rip, even after zapping the can. I'm going to try some other things to make it runa bti better soon.

-Korey

mtc3od

When the comm gets that small, from what I conclude, is that you should cut the brush to where it "decreases" the timing to give you back that low end.

mafiaracers

iTrader: (22)

Yeah, you can remove material from the outermost edges and this will reduce cogging "overlap" and compensate for the smaller comm. Bigger comm and smaller brushes=more off power free spin so I always cut the edges of my brushes.

mtc3od

when you cut off the edges of the brush do you loose power and how much percentage wise and do you also run a stiffer springs such as trinity purples, reds or do you leave the motor with the red green combo

mafiaracers

iTrader: (22)

I like the Red+ and Blue- combination. I don't feel too much of a loss of power. The motor actually stays more consistant throughout the race with smaller brushes. I also get more time between cuts because of the reduction in overlap.

mtc3od

wow, that is almost like running a 12th scale motor. What kind of brushes you use?

ritchie

as the comm gets smaller there will be a increase in rpm therefore you should drop a tooth on the pinion

mtc3od

good point. It is hard to tell where you should be geared at when you change different motors unless you have documented the use of them.

Joe B

iTrader: (1)

This is where the use of a good dyno comes in handy

mtc3od

Ya, a dyno would be nice but it's not something that is practical for me to get. College gets most of my money.

Joe B

iTrader: (1)

yea...Iv'e Been there