Normally the reason is a deterioration in the brush and
commutator condition. If you have several runs on the same
motor without maintenance, chances are the brush
has too many heat cycles on it, has turned colors,and no
longer makes good
contact. This causes the brush to wear the comm more than
it should. The end
result is a motor that arcs, runs slow, and uses more battery
than it did
when it was new.
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2) When should I change my brushes?
Brushes should be changed if they discolor or are excessively
worn (photo 3). This can happen in one run if the motor
is over geared and the amp draw is extreme (photo 2). On
the other hand, if everything is right and you are in a
circumstance where you are not hard on the motor, brushes
can last quite awhile. Typically in a competition
you will get 8 to 10 runs out of a set of brushes, then
you will see performance severely decrease until you clean
the comm or true the comm and replace the brushes.
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3) Is it important to true the commutator?
Yes. New brushes on a bad comm wear out quickly. Worn
commutators
are not round, so the brush bounces, arcs, burns, and is
no better than your
old ones were in a couple runs.
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4) Which brush is best for my application?
Go to the Trinity Website for full details for their motors.
Click Here
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5) How do I know when I need a new motor?
As a general guide it is probably best to buy a new motor when
the comm cannot be skimmed any further as it has reached
it's minimum size.
Theoretically, you can replace components and re-zap the
cans for a long time,
but sometimes it is not practical. Today's magnets are durable
but over heating will kill the field. If you have a comm lathe, and your
comm is
at the .270 inch point, it's time for a new one. Trinity
will not race an armature with a comm under .270. There
are very few runs left at this diameter.
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6) What can I do to my stock motor to make it faster?
There are several things, but good maintenance is one of the most important.
Starting with the bushings, make sure the armature
is free as it spins. If it feels as if it is binding, either run the
motor with a little
bushing buster (RC4049) or spin it with a Dremel® until
the shaft has no drag. You
do not want to go too far since the bushings will wear in
as you race. If they
are too loose, the comm won't stay in one place long enough
for the brushes to
make contact.
Next, shim the armature so that it won't touch either
bushing, there should be a
little play on each side of center. Use our Teflon®
shims (RC4030) for this. Motors create their own magnetic
centre and the armature will move to the middle of this magnetic field.
If not shimmed this way, the armature will create drag against
one bush as soon as the armature is energized and forces itself
back into its' magnetic centre.
Finally there are the brushes. There is no one brush setup.
Trinity recommend their (RC4499). For touring or heavy cars, use a full brush and
heavy spring. For 1/12 scale and light cars you can cut
up the brush and use lighter springs.
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7) What does timing in a modified motor do?
As a general rule, the more timing, the faster you go, and the
more battery you use. If racing, you need to gear down to finish a race
when timing is added.
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8) What gearing should I start with on my Buggy?
(As a guide, drop one tooth on the pinion for every turn you
drop on the mod motors)
Losi XXX 48 pitch (Stock - 23/78) (12T Mod - 21/78)
Assoc. B3 48 pitch (Stock - 22/81) (12T Mod - 19/81)
Schumacher FireBladeEVO 48p (Stock - 23/95) (12T Mod - 20/95)
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9) What gearing should I start with on my Scale Saloon?
(As a guide, drop one tooth on the pinion for every turn you drop
on the mod motors)
Losi XXXS 48 pitch (Stock - 25/90) (10T Mod - 19/90)
Assoc. TC3 48 pitch (Stock - 26/72) (10T Mod - 21/72)
Schumacher Mission 48p (20t pulley) (Stock - 23/90) (10T
Mod - 19/90)
Yokomo MR4 48pitch (Stock - 26/81) (10T Mod - 20/81)
Hudy X-Ray 48 pitch (Stock - 27/93) (10T Mod - 22/93)
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10) What does brush spring tension do for my motor?
Spring tension keeps the brush on the comm. Usually, the
higher the amp
draw, the heavier the spring. A light spring in an off road
car will arc and
burn up the brush, but a light spring in a 1/12 scale car
works great since
they are 1/2 the weight and run twice as long. In general
the lower the turn on the motors the heavier you want the
brush spring. Trinity recommend (RC4033S) for 4 or 5 minute mod
races and (RC4028S) for 8 minute mod 1/12 scale. For stock
4 or 5 minute races use either (RC4028) or (RC4389S).
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11) My car glitches with a particular motor, how
do I fix this?
Glitching can be caused by a bad comm / brush condition,
radio interference, bad capacitors on the motor, the antenna touching
metal, or the receiver mounted too close to the speed control. Start by
checking the condition of the brush and commutator. If the
comm is black either skim it orclean it using a Trinity Comm Pen (RC4053) and replace
the brushes. If it still glitches check out the article on Radio Glitches.
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12) Can too much comm drop solution wreck my motor?
Drops used in the wrong way will plug the pores in the brush
and create
arcs. If you use drops, you need to rebuild the motor more
often. Only a few drops per run are needed and the motor
should be cleaned after each run with motor spray.
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13) What's the performance difference between a single,
double, triple, quad, etc...
Rule of thumb....Singles have the most bottom end, then
doubles and so on. Multi-wire armatures usually move the power band up in the
RPM range. There are exceptions to this rule, but this is
a good guideline.
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14) What makes a 10 turn faster than a 15 turn?
The resistance of the wire. The length used for ten turns is
much less than 15 turns of the same wire and with fewer turns there is room for thicker wire.
An extreme example is a stock motor since it's 27
turns of relatively thin wire.
This also goes for wire size. The larger the wire size the
less resistance there is and the faster the motor will run.
Less resistance means more electricity can be passed and hence more power generated.
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15) When would I want to use a Torque armature over an
RPM armature? or vice versa?
Torque arms, as they are named, make bottom end. Trinity use
the torque blank in nearly every class. We can use the rpm blanks in oval
racing if the track is large, or in off road when you do not want bottom end
because of slippery track conditions. They are also good for F1 cars.
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16) How do I install capacitors on my motor and why would
I need these?
Capacitors help eliminate electronic noise from the motor
that can cause radio problems. Most motors have them pre-installed now.
If not already installed they can be fitted externally.
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17) Do I need to break-in new brushes when I fit them?
As received, the brushes in most motors should require
no break-in period. If however you elect to change to a
different type of brush, follow that brush manufacturer’s
recommendations for use and break-in.
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Running your Motor: First oil each bushing (bushing
motors only) with one drop of RC4026 Stock motor oil, install
your new motor into your R/C car or buggy, connect the motor
leads from your speed control, and off you go. If
you are unsure of how to properly gear this motor for your
application, please start on the conservative side (smallest
pinion) and work your way up until you find the optimum
gear ratio.