Replacing Motor Gear

[Gryphon]

Kos-Mos is correct about the comm lathe. A buddy of mine who is also into R/C cars bought one recently and we did a bit of fooling around with it. I'll just copy and paste his post from the MAA forums:

I have been playing around with my ICS turbo 2000 motor and Andrews CA motor. Have a look.

all pics are available biggie size at: http://s7.photobucket.com/albums/y285/Solvarex/
Thanks to Andrew for hosting the pics

Reasons:
1: the ics motor is considered crappy, it has a reputation of getting weak over time.
2: i purchased an eg700 for more torque for my icsmp5a4
3: the pinion gear on the turbo 2000 was stripped/chipped (my fault)

ok I have some tools you probably dont, but I can do this for you at your own risk. No guarantees that the motor will work after. AEG motors I have seen so far are low end compared to my racing motors.




The motor was first stripped of its pinion gear. Most hobby motors have a flat spot on the armature shaft so a gear can be removed easily by loosening a set screw on the pinion. The Ics and the Tm I have do not have this but the CA does. Options are to use a gear puller (available in WPG) or destroy the gear by cutting or sanding it off. DO NOT try to simply pry it off as you will damage your motor .




The armature is a solid stack design. this will give good torque but will lower rpm somewhat. The ICS armature has been balanced using epoxy. the job was sloppy but works ok. ( I prefer epoxy balancing over drilling holes in the armature). The CA motor had no balancing at all. The commutator (the area that looks worn) , is kinda blackened but is nice and thick, that is good for cutting. the motor wires that go around the armature stacks is simply crimped to the commutator. This is poor but is induustry standard on a cheap motor.

the ICS endbell (blue and gold) is pretty standard stuff. It is actually better than a stock TM . The motor brush hood is larger and thicker so heat transfer out of the motor will be improved. cooling holes are ok and the bushing is of good size. The CA has ball bearings!
The motor can is crappy. On the ICS no internal bracing is used to hold the magnets in place, the magnets are epoxied in place and dropping the motor can dislodge them easily. The CA has a spring as well as epoxy.

The brushes and springs are well, crap. these brushes are SUPER HARD, great for long life of the brushes (an aeg is sold under the assumption nobody will ever do maintainance to the motor), but bad for the commutator. The springs are simply too light because of the hard brushes. I will try to source some better brushes ( I made better brushes for the motor in my p90 but it is messy and imprecise for my liking.)

in the pic below you can see my motor lathe. designed for racing at the pro level, this thing is the tits for fixing up bad comms. ( you too can own one for $200 or so.) the motor is already on there ready to go. You can see the soldering has been done already but cutting has not.



a closer look of the ICS armature on the lathe.
you can see I have since soldered the bent over tabs (look for the shiny blob of solder between the stacks and the worn comm.




Finished product!



I would like to note I really didnt try to achieve a great finish as this was just to try to see if I could get any meaningful results.

RESULTS

My battery charger has a built in motor break in/test mode.

before
3.3 volts
motor consumed 3 amps
7.2 volts consumed 6.8 amps

after
3.3 volts 1.23 amps
7.7 volts 2.8 amps

That is a 2/3 improvement in efficiency.

that means in theorey you would get more shots per battery charge.

I also noted by sound an improvement in torque (faster spool up) and higher rpm ( pitch changed)

The motor also ran 7 degrees cooler at 7.2 volts after 5 minutes of running.

changing the brushes to a high silver type and soldering the leads to the endbell hoods would increase the motors output immensely. I am working on that.

*NOTE*
I have yet to take apart a TM motor.

The bad.
The CA motor has no balancing
The ICS and TM motors have bushings
TM has a poor endbell and brush hood design.

The good.
Ca has an easy to remove pinion gear.
Ca has ball bearings
Ca and ICS have a good brush hood and endbell design.
ICS has epoxy balancing.

[H0ndaJunkie]

Question for you guys......

I need a pinion puller because I've got 3, maybe 4 guns sitting here that need new motor pinions. I was looking at that $40 pinion puller that someone posted a link to, and I think it's a nice heavy duty looking unit but....

The thing is, does anyone know if that particular unit presses a new pinion on, as well as removing the old one? It looks like it might, but I don't see anything that states it for sure. I also can't seem to find that tool in any more than two places on the web for some reason.

If it properly removes and installs motor pinions, I think it would be the perfect tool for me.....that's why I'm extremely curious about it.

[yanhchan]

hey you know what I did today? Flat head screwdriver between the pinion and the piece of metal with the spring. and all I did was turn the screwdriver ever so slowly..and it came off. I tried the same thing with a penny. Worked well too