Go Back  R/C Tech Forums > General Forums > Electric On-Road
brushes and the springs >

brushes and the springs

brushes and the springs

Old 08-26-2004, 04:15 PM
  #1  
Tech Regular
Thread Starter
 
Join Date: Aug 2004
Location: Dallas,Texas
Posts: 459
Default brushes and the springs

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.????
mtc3od is offline  
Old 08-26-2004, 04:22 PM
  #2  
Tech Elite
iTrader: (22)
 
mafiaracers's Avatar
 
Join Date: Mar 2004
Location: West Linn, Oregon
Posts: 3,759
Trader Rating: 22 (100%+)
Default

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.
mafiaracers is offline  
Old 08-26-2004, 04:26 PM
  #3  
Tech Regular
Thread Starter
 
Join Date: Aug 2004
Location: Dallas,Texas
Posts: 459
Default

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.
mtc3od is offline  
Old 08-26-2004, 04:34 PM
  #4  
Tech Elite
iTrader: (22)
 
mafiaracers's Avatar
 
Join Date: Mar 2004
Location: West Linn, Oregon
Posts: 3,759
Trader Rating: 22 (100%+)
Default

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.
mafiaracers is offline  
Old 08-26-2004, 04:35 PM
  #5  
Tech Champion
iTrader: (13)
 
Korey Harbke's Avatar
 
Join Date: Oct 2002
Location: Redmond, WA
Posts: 6,169
Trader Rating: 13 (100%+)
Default

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
Korey Harbke is offline  
Old 08-26-2004, 04:40 PM
  #6  
Tech Regular
Thread Starter
 
Join Date: Aug 2004
Location: Dallas,Texas
Posts: 459
Default

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.
mtc3od is offline  
Old 08-26-2004, 04:45 PM
  #7  
Tech Elite
iTrader: (22)
 
mafiaracers's Avatar
 
Join Date: Mar 2004
Location: West Linn, Oregon
Posts: 3,759
Trader Rating: 22 (100%+)
Default

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.
mafiaracers is offline  
Old 08-26-2004, 04:50 PM
  #8  
Tech Regular
Thread Starter
 
Join Date: Aug 2004
Location: Dallas,Texas
Posts: 459
Default

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
mtc3od is offline  
Old 08-26-2004, 04:58 PM
  #9  
Tech Elite
iTrader: (22)
 
mafiaracers's Avatar
 
Join Date: Mar 2004
Location: West Linn, Oregon
Posts: 3,759
Trader Rating: 22 (100%+)
Default

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.
mafiaracers is offline  
Old 08-26-2004, 05:00 PM
  #10  
Tech Regular
Thread Starter
 
Join Date: Aug 2004
Location: Dallas,Texas
Posts: 459
Default

wow, that is almost like running a 12th scale motor. What kind of brushes you use?
mtc3od is offline  
Old 08-26-2004, 05:32 PM
  #11  
Registered User
 
ritchie's Avatar
 
Join Date: Oct 2001
Posts: 2,044
Default

as the comm gets smaller there will be a increase in rpm therefore you should drop a tooth on the pinion
ritchie is offline  
Old 08-26-2004, 05:34 PM
  #12  
Tech Regular
Thread Starter
 
Join Date: Aug 2004
Location: Dallas,Texas
Posts: 459
Default

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.
mtc3od is offline  
Old 08-26-2004, 07:46 PM
  #13  
Tech Master
iTrader: (1)
 
Join Date: Nov 2003
Location: Florida
Posts: 1,154
Trader Rating: 1 (100%+)
Default

This is where the use of a good dyno comes in handy
Joe B is offline  
Old 08-26-2004, 07:49 PM
  #14  
Tech Regular
Thread Starter
 
Join Date: Aug 2004
Location: Dallas,Texas
Posts: 459
Default

Ya, a dyno would be nice but it's not something that is practical for me to get. College gets most of my money.
mtc3od is offline  
Old 08-26-2004, 08:46 PM
  #15  
Tech Master
iTrader: (1)
 
Join Date: Nov 2003
Location: Florida
Posts: 1,154
Trader Rating: 1 (100%+)
Default

yea...Iv'e Been there
Joe B is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.