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| Issue 124 (March 2006) |
Words: Michael Wortel |
In recent years the capabilities of electric RC vehicles have taken
large, innovative steps. Batteries today are hundreds of times more
powerful than they were five years ago, and this has ushered in a new
breed of electric systems: brushless motors. Today, there are a large
variety of brushless systems available and they are becoming less and
less expensive. There is no doubt that brushless motors are incredibly
more efficient than their brushed counterparts. If you take care of a
brushless motor, it can last a lifetime, and you'll never have to see a
lathe or pair of brushes and springs again. Today's brushless ESCs
allow the use of both brushless and traditional brushed motors, but
there are a few important differences in installation and setup.
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Installation and ESC Setup
1. Before installing a brushless system, chose a location for the ESC;
keep it isolated from the receiver and steering servo. Doing so will
prevent electrical interference that would result in glitching and poor
reception. Keep the ESC in a location that will remain clean and dry as
well. Use thick, high-quality servo tape, and secure the ESC in place.
2. Bolt the motor to the engine mount, and decide how long the ESC
power wires need to be. Then cut off the remaining slack. Strip about
1/8" to 1/4" of insulation from the three power wires, and tin each of
them with solder .
3. Now, solder the power wires into the corresponding female soldering
tabs. Use a handless soldering jig to hold the wire into the female,
and heat the wire from underneath the soldering tab. Apply enough
solder to the wire until it is completely integrated into the tab.
After all three of the power wires are soldered onto the tab, cut off
the remaining wire hanging from the bottom, flush to the solder mound.
4. When using battery connectors, install them at this point. If your
brushless system is sensor-based, insert the six-wire plug into the
ESC, and use the provided harness to corral the sensor wires.
5. Finally, charge a battery pack and program the ESC according to the
default settings in its instruction manual. Make sure that your gear
selection is within the suggested parameters for your system. If your
gearing is acceptable, attach the pinion gear, using a healthy drop of
thread lock.
Setup Differences
1. When using a brushed motor with a brushless ESC, you need to install
the proper capacitors onto the motor. It's okay to use a Schottky diode
with a brushed motor, just be sure never to use one with your
brushless…the ESC will melt. Poof!
2. As you solder the power wires, you can use the single wire or a ‘Y'
method. When using a brushless ESC with a brushed motor, you must
solder three of the power wires onto the negative soldering tab, and
one on the positive.
3. When powering up your system, make sure to put the ESC into brushed
mode, again according to the setup instructions in the manual. If you
don't, the ESC will turn into a fried egg.
Setting the Brakes
In brushed motors, the added friction creates drag as the throttle
returns to neutral. This feeling is unique, and it makes handling at
high speeds feel more comfortable. In a brushless motor, the lack of
friction takes away from this comfortable drag. Most brushless ESCs,
however, have a setting that simulates the drag sensation created by
brushed motors. The drag brake setting is adjustable and can be turned
off completely. Drag adjustments are also very consistent, even at high
RPMs. This setting will also work if you decide to run a brushed motor
as well, making the ESC extremely versatile.
Keep the ESC Cool With a Fan
Today's powerful batteries challenge an ESC's ability to stay cool and
run smooth. Sometimes you are relegated to certain gear combinations.
This is based on an ESC's inability to run high gear ratios without
overheating. Thankfully, many manufacturers sell cooling fans that
attach, rather universally, to brushless ESC's. Some new brushless
systems even include cooling fans. These fans usually draw power from
the receiver, while others are integrated with the power of the ESC.
Either way, cooling fans draw very little current. Using a fan to keep
the ESC cool will allow a larger range of gearing possibilities, while
protecting your hardware in the process.
Conclusion
If taken care of properly, brushless motors can last forever. With a
brushless system, you will spend much more time on the track than in
the pits, unless you crash of course. Installing a brushless system is
not difficult, but it has to be done properly, or the ESC can turn to
liquid. The future has arrived in RC with brushless systems, making
them as powerful as nitro engines, while running silently. In order to
change the fundamental idea of brushed motors, it took something truly
innovative. Thomas Edison would certainly be proud. Brushless systems
have taken electric RC into a new arena and right into the 21st
century. Just watch for the turns, they come quickly. |
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