Help on rebuilding, and maintaining elec motors...

[bestmaxx]

Could someone here tell me what i should do to maintain my motors speed and acceleration. I dont know exactly what to do to keep it up to par. The only thing i know about electric motors is when to change brushes, and when to spray the cleaner.

[tec_41]

Well, first off....it all depends on what motor you have. If it is a stock motor (27 turn) or a 19 turn motor, you should change the brushes probably every 20 runs or sooner, more often if your racing. The comm should be cut every time the brushes are changed, sooner if possible. This is done on something called a comm lathe. Your Hobby store can probably do it for a few bucks for you. For modified motors (anything from 6-17 turns) the process should be done sooner, like 8-15 runs (15 is probably the MAX). Every time you change the brushes and cut the comm, you should oil the bushings or bearings. Stock motors usually have bushings in them. If we took the time to write a lengthy explanation on motor maintanence, could we please MAKE A STICKY?

[elecracr]

Depending on what type of motor you are running you will probobly want to cut the commutator every 10-15 runs if you are a racer. This will keep it perfectly round and running as good as the day you bought it.


EDIT: I TYPE TOO SLOW!

[bestmaxx]

Ok thats useful info.. I dont think my hobbystore has a comm lathe, do you have any idea how much a cheap one costs.... I run modified by the way, and i race it.

[AlexV2024]

just make friends with aguy that has a lathe. i cut a few of my friends motors, and it really helps to reduce their racing costs. plus cutting comms dosnt take long at all. for mod or stock i just cut before my qualifers start. that way they are nice and fresh for the quals and main. this is usually 8-10 runs which is the perfect amount. but if i could get to pratice it would easily be 12-15 runs, and thats when theres the big drop off. also when you cut also make sure the brush hoods are clean and replace the brushes if they are discolored. if they arn't then you can just reserrate them. my stock motors usually dont get new brushes for at least a month some times 2. integy makes good comm lathes and they are very inexpensive. ive see some older trinity ones go for about $50-60 and thats what my first one was. good starter lathe but now i have an integy tech lathe, so much better.

~Alex

[tec_41]

a CHEAP lathe (brand new) is around $100 i think? Not 100% on that but they are expensive. My hobby shop doesnt have one either but a guy who works there does. He just takes my armature home with him, cuts it, and i get it back the next day for $3. Making friends at the track like posted above though is a definate plus :D

[Flat]

for 27T motors... (and some mod motors)
http://www.motortuningsecrets.com/

I have just one word of caution from this site, be VERY careful when polishing the inside of the bushings. It's not hard to open up the inner diameter of the bushing when using the tips from this page.

That all

Flat.

[highroller]

This subject has been discussed before many times, try search for past posts.
The basic is to get use to the amount of wear you see based on use then use that as when you perform maintenance. The baasic items you need are:1. motor cleaner or automotive brand m electric motor/contact cleaner 2. lubes (3in1, sewing machine/clipper oil, auto synthetic oils) 3. comm/brush cleaning stick (remove the glaze and small pitting) 4. replacement brushes & springs 5. assortment of pinions (gearing motor correctly eliminates most of the wear).

Get in the habit of inpecting motor after each battery pack, then extend the inpection as you become more familar with the wear motor gets based on your type of use. Stop and inspect vehicle anytime you notice a change in how it runs -continuing to run it may do more damage. Motor problems can sometimes be confused with other electrical issues slowing may be confused with a battery dumping. Car stalling needing a push to get going can be confused with a receiver or esc problem generally it's because brush has worn to the point springs can no longer provide proper tension-this interfers with the brushes abitlity to conduct current. Improper gearing where motor get too hot is again confused with battery dumping car will run fast at the start but slow after 1-2 minutes.

Using a lathe to true the comm is almost unnecessary if you use low content silver brushes for bashing, in competitive levels each person has a routine based on wear or what they feel brings back motor performance. Comm gets trued after one battery pack up to 12 (the more runs you put on comm the more material has to be removed leading to shorter armature use), with some changing brush after 1 run, to other changing brushes when significant wear is notice - some will continue to reserrate or clean the brush until it is too short to for springs to provide adaquate tension.

[nitro_newbie]

will the motor in a t4 be needed to be cut on a lathe and replace the brushes if u just bash in the sand or the street or race alittle on the side


thanx

nitro_newbie

[highroller]

Several things would determine if comm turing is really needed: brush compound, brush configuration (serrated or non serrated), motor's power output, and number of cells used. Things that would lead to more wear to comm would be med to high silver serrated silver brushes, high reving motor that's either improperly geared or using springs that are too light, using more than 6cell packs.

Even for bashing by using a spring with the right tension may minimize wear by reducing brush arching and bouncing, staying with low silver or what used to be called Stock Japan brushes (mostly a graphite/copper makeup), staying with 6cell vs 7 or 8 cell packs will reduce comm wear to a minimum sometimes only requiring the use of a comm stick to remove the tarnish and small pitting on comm.

[redheat8]

To properly maintain a motor alot of what has been said is true and very good advise, but I feel that the motor should be taken apart and cleaned not just sprayed , the comm. stick is a very good investment the well pay for it's self over time can be used to clean the comm and brush ends, youll get more run time out of your brushes and comm buy keeping them clean, RED

[bullmastiff]

I think bestmax is right.

For example, I just got into electrics. I own four stampedes, one for me which I am making brushless. Three others , one for each daughter and one for the wife.

There's are brushed. But I have never opened up a motor so I couldn't do work on a motor to save my life.

I've been trying to find a good site that shows in pics on how to do proper motor maintenance.

So far my daughters brand new motors have only about 2-3 runs but I need to know how to work on them.

A good thought out post with all the detailed specs and descriptions of motor taking apart and maintenance would be invaluable. Then make it a sticky.


Bryan

[highroller]

There are a couple of links at the beginning articles with pictures on setting up and maintenance of motors. Stock and 19turn spec those with fixed timing are the easiest to take apart and rebuilb provided you keep everything in the order they were - springs are generally of different tension for the positive and negative terminals, brushes if reused or replaced should also be replaced the same, the shims and washers as need to be replaced in correct order. After that most everything is easy. Motors with adjustable endbells are like stocks motors, except for one thing - you need to reorient the endbell in the correct order or motor may turn in wrong direction or you set it at the wrong timing. First before taking anything apart is to mark one of the endbell retaining screws, with a corresponding mark on the motor can (use a permanate marker but it may come off it sprayed with motor cleaner before you reassemble) you align these marks when reassembling. Now you can remove brush springs, brushes, loosen endbell retaining screws enough to rotate endbell to the point that it comes off, the retaining ring should also slip off (do this over a towel so shims or screws don't get lost). Look inside the endbell, and inside of motor for shims or washers that sometimes comes off and get stuck. If you completely disassemble motor you can use several methods to clean parts: soap and water are the cheapest - also the safest for those with chemical allergies, motor cleaner etc. After cleaning replace the shims in correct oder - some use 1-2 in the output shaft end (where pinion is attached, on the comm end some use a brown (phenolic) washer, then 2-3 metal washers or a teflon/plastic washer goes on the end. Both the Phenolic and teflon washers act as insulators to prevent comm from grounding out against the endbell as aramtures shifts. If you want to get a little more power out of motor additional things can be done.
1. Align armature - place armature in motor can with endbell loosely attached, spin armature several times noting it's position. Apply shims (sometimes an assortment of motor shims is required) so armature in now centered better in magnet field and to minimize armature end play to about 1/16 to 1/32 of an inch.
2. Align brushhoods so brush is wearing down the middle. For this use an old set of brushes (kit supplied brushes or non race type can be use to test). Use a brush alignment tool that allows you do alignment to each brush hood separately (Racers Edge and a couple others make one) although it says to align both most cases one hood can be misaligned a little. Some use an old brush color the face of brush with a marker (red, black) to indicate the wear.
3. Now assemble motor, or take another step with new ones polish the armature shafts with some chrome polish, use a pipe cleaning filter or a 1/8 diameter piece of metal attach it to dremel and breakin or polish face of the bushings. This extra work will allow the motor to turn as little better b reduceing the friction.
4. If you are replacing the brushes, or trued comm it is a good idea to reseat the brushes (breakin) using a couple of methods. One is to use a battery pack (4cell) then run until brush start to contour to the shape of comm, some use a battery operate Dremel (this requires some modification to the tool to invert the battery pack), other use a slave motor or breakin/motor run feature from charger or power supply, other use 2D batteries. The idea is to minimize arching and heat buildup while brush is breaking in. One way to tell when brush has reached the right breakin point - motor may run rough - with noticeable arcing then smooth out with a slight pickup in the rpm range - there will still be some arcing. If arcing is still presistant it's probably due to brush springs being too light or comm is out of round go to the next tension spring or bend brush spring so it increases tension. For modified motors the ideal setting for breaking in brushes is to loosen endbell the rotate it to the zero degree mark - motor turns with less speed, reduces arcing. The zero degree can be identifed two ways, three if you have a motor timing guage. The point between the two mounting screw holes on the output shaft of motor is the center of the magnets or zero degree mark, most motor cans have a small indention like a - near then endbell end of motor can both marks are parallel to each other. 1/8 inch represents roughly 5degrees of timing.

There is also a link on the Hobby Talk site with a book written by Jim Greenemeyer called Big Jim's Black Book -motor secrets. Other sites rc racing, rc oval etc have done features and articles on motor tuning and maintenance. Look for issues of RCCA when they do articles on motors, it the best way of getting an idea of the parts that make up a motor, how to take it apart and assembling it. Your first couple rebuilds may be hard, but after that it gets to be easy.

[bullmastiff]

Thanks highroller that really helps. I think I will see if I can find some of the other places you talked about so I can get knowledgeable about these motors.

Bryan