Tuning motors with brushes
03-25-2004, 09:14 AM
#16
It felt flat because you took away the part of the brush that supplies the majority of the power. Current flows around the outside of anything. On a brush, it flows directly across the furthest edges of the face. When you shave those away, the current has to find a new path, this new path will cause the motor to feel a little soft. In Mod racing, this is great because the brush will seat itself much quicker and you'll notice the effects much sooner and they will be far more prevelant.
-Chris Woods
-Chris Woods
03-25-2004, 10:17 AM
#17
I think thats why motors feel best when there are still slight serrations on the brush. Because the electrons flow over the outside, there are more paths for the electricity to take.
03-25-2004, 01:02 PM
#19
I am reffering to the condition of the brush where its broken in, as in it is countored to the comm, but there are still valleys of serrations left. Probably a negligable difference in pressure per square inch. But that could be it. Why not then does the motor perform on the track that way with a stiffer spring.
03-25-2004, 03:33 PM
#20
how do you guys 'tune' your bushings, i heard polishing them will help, is this rite? and wot else can i do
Cheers
Stew
Cheers
Stew
03-25-2004, 06:41 PM
#21
Tech Rookie
HMMMMMMM
KMMMMM....Silver brushes wear down faster than copper ones for all you rookies who didnt know.
CATS
CATS
03-25-2004, 06:46 PM
#22
Tech Rookie
ANOTHER THING
It helps to spray "power shot" (motor cleaner) on to your comm every few runs before you run your car, it will help you brushes last longer. You can get these kinds of cleaners at: www.towerhobbies.com 
03-25-2004, 07:03 PM
#23
Bushings are the most important part of a fast stock motor. The freeier you can get the arm to spin, the faster and cooler it will run.
Take the bushings out of the motor with a nail punch-out. Take 800 grit sandpaper and roll it up small enough to fit into the bushing hole. Put one end of the sandpaper into a drill and spin it for a minute or so. Then spray it out very well. Next, take some 2000 grit sandpaper and do the same thing as the 800. Then spray it out very will. Next, take "Blue Magic" chrome polish and put it on a q-tip...a ton of it. Insert it as well as possible into the bushing and chuck the other end into the drill and set it spin for about 30 seconds. It will turn very black. Repeat this process until it is no longer black. Spray out the bushing after every time with the blue magic. Now the bushings are like bearings.
Next, take one of the motor shafts and polish it. Take the 800 grit and while holding the arm in your hand, turn it. The shaft will become very "not shiny" and the sandpaper will have silver on it. Spray it out. Next take the 2000 grit and do the same thing. Spray it out. Lastly, dip the arm shaft into the blue magic and take an old while t-shirt and spin it in the same fassion as you did with the shaft. The shirt will turn very black like the bushings. Spray it out very well.
The key is to take your time, this is generally a very long process and if done right, your motor will run like its using bearings. Good Luck!
-Chris Woods
Take the bushings out of the motor with a nail punch-out. Take 800 grit sandpaper and roll it up small enough to fit into the bushing hole. Put one end of the sandpaper into a drill and spin it for a minute or so. Then spray it out very well. Next, take some 2000 grit sandpaper and do the same thing as the 800. Then spray it out very will. Next, take "Blue Magic" chrome polish and put it on a q-tip...a ton of it. Insert it as well as possible into the bushing and chuck the other end into the drill and set it spin for about 30 seconds. It will turn very black. Repeat this process until it is no longer black. Spray out the bushing after every time with the blue magic. Now the bushings are like bearings.
Next, take one of the motor shafts and polish it. Take the 800 grit and while holding the arm in your hand, turn it. The shaft will become very "not shiny" and the sandpaper will have silver on it. Spray it out. Next take the 2000 grit and do the same thing. Spray it out. Lastly, dip the arm shaft into the blue magic and take an old while t-shirt and spin it in the same fassion as you did with the shaft. The shirt will turn very black like the bushings. Spray it out very well.
The key is to take your time, this is generally a very long process and if done right, your motor will run like its using bearings. Good Luck!
-Chris Woods
03-25-2004, 07:18 PM
#24
Tech Elite
Guys;
Really there becomes a point of diminishing returns for all of this and I surely would NOT recommend using Sandpaper (even 800 grit) inside the Bushings.
All that is needed is some Chrome Polish on the Armature Shaft and Bushings the first time you break the Motor in (You're going to disassemble the Motor ANYWAYS). The normal contact of the Metal parts coupled with the Polish, will do the Job.
Afterwards, disassemble and flush everything out with Motor spray.
Really there becomes a point of diminishing returns for all of this and I surely would NOT recommend using Sandpaper (even 800 grit) inside the Bushings.
All that is needed is some Chrome Polish on the Armature Shaft and Bushings the first time you break the Motor in (You're going to disassemble the Motor ANYWAYS). The normal contact of the Metal parts coupled with the Polish, will do the Job.
Afterwards, disassemble and flush everything out with Motor spray.
03-25-2004, 07:22 PM
#25
Yeah Pops I agree...
I used toothpaste and an armature shaft for about 30-40 seconds and it made my bushes too loose on the armature, motor runs far less efficiently.
I have found there to be a difference polishing the armature shaft and also polishing the face of the bushing. You are far more likely to get good power from the right set of brushes and springs etc.
I used toothpaste and an armature shaft for about 30-40 seconds and it made my bushes too loose on the armature, motor runs far less efficiently.
I have found there to be a difference polishing the armature shaft and also polishing the face of the bushing. You are far more likely to get good power from the right set of brushes and springs etc.
03-25-2004, 07:39 PM
#26
03-26-2004, 02:36 AM
#27
Tech Master
Originally posted by PitCrew
NO. Electricity FLOWS FROM negative TO positive. You fall asleep in science class?
And he is correct about the spring tension, but he had the wrong description of why it is that way.
You ever hear about how they plate parts with say...cadnium? They hook the anode to the part (thats positive) and they use the cathode to apply the material (cathode is negative) The electricity flows from negative to positive, carrying with it particles of cadnium, adhereing them to the part.
Same with the brushes. If the brushes didn't wear out due to friction, the brush on the positive terminal would eventually be covered with copper because the electricity is pulling the material from the comm, trying to deposit it onto the positive brush.
Please, ask anybody that acctually knows something about electricity. negative to positive.
NO. Electricity FLOWS FROM negative TO positive. You fall asleep in science class?
And he is correct about the spring tension, but he had the wrong description of why it is that way.
You ever hear about how they plate parts with say...cadnium? They hook the anode to the part (thats positive) and they use the cathode to apply the material (cathode is negative) The electricity flows from negative to positive, carrying with it particles of cadnium, adhereing them to the part.
Same with the brushes. If the brushes didn't wear out due to friction, the brush on the positive terminal would eventually be covered with copper because the electricity is pulling the material from the comm, trying to deposit it onto the positive brush.
Please, ask anybody that acctually knows something about electricity. negative to positive.
actually electrons dont flow they charge each other.
i suppose i should put my diode the other way round?so the positive side is on the negative?
lol.i think you fell asleep!
03-26-2004, 11:18 AM
#29
TRF
Man dude, do some investigation before you speak up.
Do you even know why the diod is on the motor???? I'll tell you later after you flounder a little.
Man dude, do some investigation before you speak up.
Do you even know why the diod is on the motor???? I'll tell you later after you flounder a little.
03-26-2004, 11:43 AM
#30
what chrome polish do you recommend pops? I am thinking of trying this with my stock motors since it sounds alot easier that the other methods that I heard of.
So basically summing it up, you put some chrome polish ( how much? ) on the shaft, the bushing ( inside and bottom racing the comm? ) and run the motor for 40 seconds on X ( how much? ) volts and it will do the polishing for you?
Thanks!
So basically summing it up, you put some chrome polish ( how much? ) on the shaft, the bushing ( inside and bottom racing the comm? ) and run the motor for 40 seconds on X ( how much? ) volts and it will do the polishing for you?
Thanks!
