411 of RC Motor Timing, Tuning, Cleaning, and Brush
and Spring Upgrades
Supercharging a Modified Motor
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 communicator 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 communicator
(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 Communicator Pen and what is it?
A communicator pen in basically a retractable fiberglass stick that you
stick in the communicator hole and twist the axel a couple of times to
clean all the junk off the communicator. Using it regularly every
couple of runs, helps reduce communicator 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
comm (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 comm wear, lowest brush wear, high lubrication and the lowest
power. The copper brushes are recommended for modified racing. They have
the medium comm 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 comm 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 communicator
Soft brushes:
* 35 to 50 percent metal content
* less horsepower
* easier on the communicator
* 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 comm 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 comm 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
communicator 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
communicator 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 communicator 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.
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