Electric RC car motors and parts
Electric rc car motors don't really provide the raw power that nitro engines do, but they are much quieter and cleaner. And, they don't need anything to start them, you just flick the switch and go!
Essentially, when talking about brushed (not brushless) motors, there are two types of electric motor for rc cars and trucks; stock and modified.
A stock motor is one that cannot be changed in any way; it comes from the factory and must be used as it is. The chances are, if you buy an RTR (Ready To Run) electric rc car or truck then the motor it comes with will be your average stock motor.
A modified electric rc car motor is generally more powerful and should only be used with a separate electronic speed control (ESC). Adjustable timing and ball-bearing races are typical features of modified motors.
The picture below shows that there isn't much to tell the two apart, at least from the outside...
The newest kind of electric motor that has been developed for rc cars and trucks (as well as rc aircraft) is the brushless motor. These offer huge amounts of power, sometimes up to 300% more than a normal brushed motor.
Brushes are an essential component of traditional electric motors and need replacing now and again as they wear out. Brushless motors eliminate this problem as there are no brushes used.
Brushless motors are more expensive, but as with everything radio control the prices will come down with time as they become more widely available. Although new to the rc world, it won't be long before brushless motors become 'the norm' and are used in every rc vehicle.
RC car drivers who are serious about competing will be using brushless motors, but for the beginner the previously mentioned stock and modified brushed electric motors are perfectly adequate.
Speed Control
A speed control is the device that determines how much voltage goes into the motor from the battery pack, and is controlled by the throttle stick or trigger on the transmitter.
There are basically two kinds of speed control; mechanical and electronic (ESC). Mechanical ones require a servo and linkage to operate and are more prone to experiencing problems, whereas electronic ones are much more direct and offer smoother control of the motor.
Some lower budget rc cars and trucks come with a mechanical speed control; upgrading to an electronic one would be a sensible thing to do. It's a very good idea to get an ESC that has 'reverse' feature, not all of them offer this almost essential requirement.
Battery packs
All electric rc car motors require a rechargeable battery pack to operate. Traditionally these are made up of 6 or 7 Nickel Cadmium (NiCD) or Nickel Metal Hydride (NiMH) cells that are tightly wrapped in a strong plastic heat-shrunk film.
But in recent times, newer lithium-ion polymer (Li-Po) packs are being used. Li-Po packs, like brushless motors, are new technology that will undoubtedly become commonplace at the track. Li-Po motor packs give out a tremendous amount of power due to their high capacities. Coupled with a brushless motor, a Li-Po pack powered rc car will win a race hands down!
A common battery pack (non Li-Po) size is 7.2 volts, but other voltages can also be used depending on the motor. It's imperative that you use a battery pack that is compatible with the size of motor, or you'll end up burning something out.
If in doubt, always check the instruction manual or ask someone at the place where you're buying from to make sure that the battery pack that you're purchasing will be ok for your particular model.
A standard battery pack takes around 20 minutes to charge on a fast charger, so it's always a good idea to carry a couple of extra packs with you - this way you can always be driving your car while one pack is charging (read about battery chargers here).
Related pages
Electric RC cars - an overview and model examples.
Nitro rc car engines - learn the basics of nitro car power.
