New Site Format
     As you know
  StampedeProject has
  become way more than
  just Stampede, Traxxas,
  to now include other
  RC brands, accessories,
  and cars. I still don't sell
  anything, I just
  enthusiastically promote
  those RC products I think
  are great.
     Take a look through
  the above links.
  I simply had too much
  information for my
  old site format.
  More fun projects
  coming...
  - Tony

  StampedeProject.com

  Please Private Message
  me Here on the
  Traxxas Forum    

  Copyright 2007
  all rights reserved 

411 of RC Motor Timing, Tuning, Cleaning, and Brush and Spring Upgrades
Supercharging a Modified Motor and Electrics Upgrades

This past week, I realized during a routine motor cleaning that all my motors' brushes were looking a little worn and were in need of replacement.  I am not the guy who is going to buy a motor lathe to re-cut the Commutator on the motor, but I am willing to solder a new set of brushes on the motor can and pop in some new springs to revive my aging motor and get some extra mileage before they are ready to retire.   While I was at it, I though I might as well see if there are any upgrades I can do for a little extra horsepower and/or torque.  The confusion began, which springs, which brushes, etc.  Motor tuning is a subject that I think has received little attention online and pushed me to do some research on the basics of RC motor tuning.  First off, with general maintenance, a motor for the regular basher will typically last around 3-4 brush and spring replacements, however noting that is more based on your motor care and driving style and for me the gritty clay soil in my part of the US.  Here is what I found for the basics.

Motor Basics from RCRacingUSA.com - Answers a lot of questions

Motor Maintainance 101 by MisBehavin-RC

Motor Timing 101 by MisBeahvin -RC

Do I need to cut my Commutator (com)?
That depends on a variety of factors, if it is deformed even slightly, probably yes.  Someone at your local hobby shop may cut it for you for a charge.  Don't spend much more than $5, because a completely new armature starts in the $15-20 range.  I usually religiously use a com pen (a fiberglass pen that clean the com) and use a motor until the com shows some more serous deformation and then replace the motor.  If you race, you will probably want to cut your com on a regular basis, but a com lathe is about $75-100.

How do you use a Commutator Pen and what is it?
A Commutator pen in basically a retractable fiberglass stick that you stick in the Commutator hole and twist the axel a couple of times to clean all the junk off the Commutator.  Using it regularly every couple of runs, helps reduce Commutator wear and increase motor performance.

Brushes and Springs O My.
Now that you know your way around the motor and have read those above articles, (if you haven't you should) we have a couple other issues to tackle for our replacements and upgrades. 

On Brushes
According to RCCARTIPS.com and RCRacingUSA.com and my interpretation/research:

Electric motor brushes are usually made of copper, graphite and
sometimes silver. In general there are the copper-graphite and the
silver-copper-graphite.

A brush made from a silver compound is recommended for stock racing. Silver Brushes also leave sludge behind that can only be removed by lathing the com (not for the novice). Silver should be used for competitive racing where the last percentage of power is needed to win. A brush made from a copper compound is recommended for modified motors (such as the Trinity Speed Gems series). Copper brushes don't leave behind sludge and works best with high RPM motors.

The graphite brushes are not really recommended for racing. They have the lowest com wear, lowest brush wear, high lubrication and the lowest power. The copper brushes are recommended for modified racing. They have the medium com wear, high brush wear, lowest lubrication and medium power. The silver brushes are recommend for stock racing. They have the least amount of resistance. The have the highest com wear, medium brush wear, medium lubrication and highest power.

Graphite-low copper brushes:
* used in economy brushes and motors

Copper-Graphite brushes
* Used in modified motors
* Produces more power than Graphite-low copper brushes, but less than silver-graphite brushes
* Best option for non-racing RC'ers
* Does not leave behind sludge like silver brushes and cause much less maintenance.

Silver-copper-graphite brushes:
* used in high performance brushes
* produce more horsepower
* easily damaged by overheating (by over gearing)
* may not be suitable for heavy current applications

There are also the terms hard and soft brushes.

Hard brushes:
* 70 to 80 percent metal (i.e. copper or silver) content
* more horsepower
* harder on the Commutator

Soft brushes:
* 35 to 50 percent metal content
* less horsepower
* easier on the Commutator
* high graphite content"

There are also serrated brushes which are overall easier on lower turn (higher RPM) motors.

On Springs
As a general rule when you replace your brushes also replace your springs and throw the old brushes and springs away to avoid confusion.  The springs will relax over time and due to motor temperatures and need replacement like the brushes.

According to this article from RCRacingUSA.com

"Springs come in a variety of different degrees. 90, 115, 135, 150, 180. Each type of spring puts a different tension on the brush. The most common of the springs are the 135 degree and 150 degree springs. The 135 degree springs will give you more RPM, less power, same torque and less com wear than a 150 degree spring. The 150 degree spring will give you less RPM, more power, same torque, better results overall for stock and modified racing and more com wear than a 135 degree spring. The 135 degree spring is the most common type of spring used."

Stiff Springs (higher Degree - 180)
* Less RPM
* More Power
* Same Torque

Medium Springs (Someplace in between)

Soft Springs (Lower Degree - 90)
* More RPM
* Less Power
* Same Torque

So what do I choose? Which combination do I pick? 
That depends, let's say that you have figured out gearing and are not overheating your motors on a regular basis to the point of meltdown - i.e. 5 second rule - can you touch the motor for 5 seconds if not it's too hot.  If you have that handled, you could start experimenting with silver content brushes and stiffer springs.  I would recommend picking up a Commutator pen to clean the com after every couple of sessions.  Buy some different brush types (obviously that will fit your motor - see you manufacturers site), some different spring weights and use different combinations to see what works.   Since all the brushes and springs pretty much look the same, a tip here is to also pick up one of those little plastic compartment boxes and label each compartment with the type of spring or brush you are putting in it.  Extremely anal, yes, but it will prevent you from going "now... which one was this?"

Suggestions for Soup-ing up that Modified Motor
Let's say you have a Trinity Speed Gems 17T or 15T such as mine and you have been looking at Trinity's site for brush replacements.  You could just buy what is the manufactures replacement, typically a medium spring and graphite/copper brushes. clean the motor and hit the Commutator with the com pen and get a boast from your current level of performance.  However, you could probably get about the same performance as the next motor up in the line by going to a better (higher silver) brush set with dual shunts (dual wires for higher current) and new medium springs.  Going hog wild for power would be pure silver brushes and heavy springs.  This set-up however will require frequent attention to the com and will greatly reduce the life of your motor.

As an example - A manufacturer replacement part would be the RC4380EP Hard Copper/Graphite brushes.  For more power, the RC4383EP Hard Copper/Silver brushes noting that the Ultra High Silver Hard may cause some sludging and heavy Commutator wear (regular maintenance with you communication pen will be required for the upgrade in power). The key here for the general basher is to limit time working on the motor (unless you enjoy that kind of thing) and go with a lower silver or even non-silver brush and you and your motor will enjoy a long life together. 

Can I buy a new Armature and put is in my SpeedGems can?
According to a recent email I received from Trinity tech support, yes.  In fact people do it all the time. Let's say you have a 17T pro Amber motor, you could stick a 16T Chromium Armature or 15T Titanite armature in the can and have basically a new motor.  Your could even spring for one of the new Cobalt armatures to really shake things up.  The downside is that by the time you buy a new armature, springs, and brushes, for another $10 you could just buy a new motor.  Also the magnets do loose power over time so, it may not be "exactly" like a new motor.  That said it is nice to know that you can swap things around should a can get damaged.

General Electrical Upgrades

One of the biggest improvements is to convert the high resistance stock battery plugs to low resistance high current Deans or Power Poles.  These performance plugs allow much more current to easily flow from your battery to your ESC and motor. While you are at it I would also recommend upgrading all the power cables to 12 Gauge Deans or other higher performance (low loss) power wires.  These larger sized power wires can more easily carry current from your battery to your ESC and Motor.  You will see a little more zip once you do this change over.