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Post by pceng on May 20, 2014 11:05:22 GMT -7
Could not find thread on break-in of brushes. Have seen posts about or referring to it at times. Remember seeing things about time, voltage, one brush vs. another, even chassis types.
Ran cars going to NZ (is that right) for 15 mins. today. First 5, then 10 min. Had messed with brushes and pressure, was reason. X - Traction and 4G. Ran both at 9v's, X - traction benefited more than 4G. Got me wondering if there was a time frame that works for different chassis.
Figure everyone that runs cars for break-in will have different techniques to do so. If all chime in, with their technique. We could compare. Perhaps time frames, voltages and so on that work best would be apparent, and help all......
....................... Peter
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Post by pceng on May 24, 2014 13:18:44 GMT -7
Could not find thread on break-in of brushes. Have seen posts about or referring to it at times. Remember seeing things about time, voltage, one brush vs. another, even chassis types. Ran cars going to NZ (is that right) for 15 mins. today. First 5, then 10 min. Had messed with brushes and pressure, was reason. X - Traction and 4G. Ran both at 9v's, X - traction benefited more than 4G. Got me wondering if there was a time frame that works for different chassis. Figure everyone that runs cars for break-in will have different techniques to do so. If all chime in, with their technique. We could compare. Perhaps time frames, voltages and so on that work best would be apparent, and help all...... ....................... Peter Sooooo....... maybe nobody does break-in's any more...... must be behind time again......... what's the new secret ? |
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Post by AJR on May 26, 2014 8:10:55 GMT -7
Peter....right or wrong I don't break in my brushes for very long. I haven't even been lapping my gears lately. I'm sure there is a certain amount of break in that is needed. What I have been trying to do on the last few builds is give them more pre race track time for break in. Maybe 10 to 20 full power runs. I know that lapping gears is beneficial, but I have not had much luck with it. I just try to make sure everything is smooth when I put cars together.
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Post by Hemi Hunter on May 26, 2014 9:18:13 GMT -7
An old trick I learned from the FRAY Racers was to hold the brush with a set of metal needle nose and heat it up a little with a lighter. Then wipe clean with a damp paper towel and it should be good to go.
They did this to JB brushes and said it was a quick way to remove flash from the brush and breakin without stressing the motor. I have done this back in the day but didn't really notice any performance gain.
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Post by pceng on May 27, 2014 17:41:41 GMT -7
I think that the breaking in of brushes has become an after thought for me.......... messin around with stuff other than race prep has had me neglecting this.
Did not like the way brushes were wearing when I looked at cars before race. Increased pressure then ran at 9v's. 5 then 10 mins.......each time X-trac had noticable increase in speed or rpm......not so much so with 4g.
Remember when first joining site & proxy racing, that those members who spent time with this process. Were the most successful when it came to racing.
Think this is more important with pancakes than inlines. The brushes being larger in diameter have a greater chance of being off so to speak. The face of the brush should contact the comm with as much possible surface area as possible. But being sprung and messing with pressure tends to alter the way a brush will contact comm.
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Post by AJR on May 27, 2014 18:04:40 GMT -7
I remember the same thing about when we first joined. I've gone back and read through some of the races and I recall some of the guys talking about their methods and length of time tuning. I do spend a lot of time on most of my builds. These kinds of questions get me to thinking about stuff. I should probably spend more time in those areas. A builder has to put the time in for the speed in all areas IMHO. I do polish the comm when allowed to make sure it is smooth and I sand each of the brushes on a piece of 600 to 1000 grit sandpaper for flatness. So I kind of consider that pre break in. Haven't noticed any abnormal wear or odd wear patterns.
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Post by pceng on May 29, 2014 8:22:02 GMT -7
Hey guys, "Seating"........was the word I was looking for. More important with pancakes than inlines due to size and shape of brush and comm. Being smaller and having a curved face brushes for inlines break in and seat themselves pretty quickly. They are also more fixed or locked into position than the floating brushes in a pancake.
Seating the brushes in a pancake, so that as much brush as possible contacts the comm. Will smooth operation, and get timing as equal as possible between poles. Every pole may ohm the same, but if your brushes are passing different amounts of current due to varying size contact patches your timing is off.
Have seen articals by Fray guys who test arms by running in both directions. Iff an arm runs better in rreverse they adjust brush contacts on chassis so brush is tilted slightly and there is less pressure on leading edge of brush. Artical went into electronic theory and loading and unloading of poles on arm. Felt like school.again....... oh, should mention if alot of build up is found betweem two comm plates and not the others, comm plate is probably warped whether visible or not. Had a stock arm go up in smoke because of this. Two races, changed tires first test run and smoke........... gap between arms was filled with brush shaving and plates welded together..........
Have to try and find artical again, was half awake..........
................ Peter
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Post by pceng on May 29, 2014 13:10:57 GMT -7
AM radio, could not remember before........... plug radio into same outlet as power supply....... tune to none station....... static....... run car at constant............. static on.radio will change as brush pressure is tested. Least amount of static is close to best brush tention.....
NEVER TRIED THIS ......... but will give it a try one day.....
................. Peter
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Post by dave632 on Jun 8, 2014 18:52:45 GMT -7
What you are talking about is RF noise, never heard of the AM radio method but is sounds like it would work.
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Post by pceng on Jun 8, 2014 20:17:23 GMT -7
Kind of like - a poor man's audio oscilloscope......... AM is amplification modified......... any change in current source will change static heard.......... or any change in draw on source does same.......
One good thing about it is...... you can sort through brands of brushes without having to re-assemble, go to track, then tear down & start over........ in the case of a pancake arm - just remove idler gear & run w/different brushes.........
Truth is, I just do it by ear........ (without radio)
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