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Frequently Asked Questions & Techinical Information

Source: Author: Visit:42 Release time:2014-07-17 22:20

Q. What does “brushless” mean?
A. Though inexpensive, traditional “brushed” electric motors offer short run times and limited power. Current passes into the heart of the motor through soft to semi-hard blocks of material called brushes which contact the spinning commutator. Friction from this contact reduces power and causes wear, eventually requiring brush replacement.
“Brushless” motors avoid these inefficiencies. Current passing around the outside of the motor’s can causes magnets on the motor shaft to follow in a circle (imagine the passing current acting like one magnet, pulling the magnets on the motor shaft toward it). Brushless technology is more expensive, but also more efficient - and can be MUCH more powerful!

Q. What advantages do brushless electronics have over glow engines?
A. Previously, only glow engines could achieve the performance now available from brushless motors, ESCs and accessories. Brushless technology, however, has benefits that glow power can’t match.
  • Cheaper - Only a charger and batteries are required…no fuel, glow plugs, starting equipment, or maintenance accessories to replenish over time.
  • Simpler - Just connect the battery to the ESC and go!
  • Cleaner - No fuel spills and exhaust residue to clean, and no fuel odor.
  • Quieter - An important consideration with non-modeling neighbors.
  • Maintenance-free - Compared to glow engines, which require maintenance and tuning.
Q. When I use a brushless motor, do I also have to use a brushless ESC?
A. Yes. Brushless motors will not work with non-brushless ESCs - the two technologies are completely incompatible. A brushed ESC just pumps out current like a fire hose pumps out water. A brushless ESC spreads current in a precise pattern to different places in the motor with an AC current as compared with DC for brushed motors.

Q. How does motor choice affect my model's performance?
A. In electric motors, an increase in winds means an increase in top end speed. A decrease in winds means an increase in torque, or acceleration. Conversely, more turns means more torque/acceleration, while less turns means more top end speed.
Pinions and spur gears work the same as turns—more teeth, more torque, less teeth, less torque but more speed.

Q. How do I break in an electric motor?
A. Ideally you'd like to run the motor at about 1/3-1/2 it's rated voltage with no load (without prop) for an hour or two—long enough to wear the brushes down without arcing.
R/C car modelers have special transformers for optimum breakin on high performance motors. If what you're working with is a typical 05 can motor, you can make your own system that works fairly well. Start with 2 alkaline D cell batteries and some spare 12 gauge wire. Simply hook the batteries up in series so you have a 3 volt power source and hook the wires to the appropriate terminals on the motor. Let the motor run until the batteries are dead.

Q. Is only one winding energized at a time?
A. In a three phase Y-connected stator, two or three windings may be energized at once. This makes efficient use of windings and develops higher motor torque.

Q. What type of power is applied to the coils?
A. Most brushless motor controls employ pulse width modulation (PWM) techniques to keep electronic devices cooler, thus allowing for smaller components.

Q. Are Hall sensors used exclusively?
A. Although Hall sensing is quite common, many industrial applications use electronic commutation schemes with resolver or encoder feedback.