How to choose an ESC and Motor for your RC
Electronic Speed Control (ESC)
The first thing we should do before we race out and buy a new motor, is to check the actual size and measurements of our RC Vehicles motor space. There are various motor sizes available for different types of RC Vehicles. If you check your RC Vehicle specifications, they will normally specify what size motor your RC Vehicle is designed for.
The most common motor size used in RC Vehicles is often called the 540.
The 540 motor size is often used in many lighter 1/10 size RC Vehicles, with the larger 550 or 1/8 sized motors used in heavier 1/10 and 1/8 scale RC Vehicles. Larger size RC Vehicles use even larger size motors, and your smaller size RC Vehicle generally uses 370 or 380 size motors.
Not only are there differences in the length and the diameter of the motor, but there are also differences in the motor shaft diameter. The most common shaft size is 1/8" (3,175mm). Many larger motors use a 5mm shaft.
The diameter of the shaft directly influences on the selection of gears available.
The mounting hole positions in each motor are also dependant on the motor size. It is because of all these factors that, it is very important to check what size motor fits your RC Vehicle.
Another thing to consider is whether it is a brushed or brushless motor. If you are changing from a brushed to a brushless motor, don't forget you will need a brushless ESC.
Motors are available sensored or sensorless. The difference is; sensored motors have sensors inside the motor that register the position of the rotor. Sensored motors are more responsive from low rpm and give a more precise feel. Sensored motors are used more in competition racing than sensorless motors. Sensorless motors are cheaper to buy and are used more in RTR (Ready To Run) RC Vehicles and general hobby use.
An ESC needs to be compatible with your motor, as some ESC's can only power sensorless motors, while some ESC's only work with sensored motors.
The power of a motor is indicated in "kv" or "turns" and sometimes both.
A motors kv means its RPM per volt of electricity, e.g.: 3000kv. The higher the kv the more power the motor has.
The turn number, e.g.: 8.5T or 13.5T, refers to the number of times the wire in the motor is wrapped around the stator. To make it easier to understand - just remember,
The fewer the turns, the more power the motor produces.
But before I go..
What is the Stator? I hear you ask,
Both the Stator and the Rotor are parts of the electrical motor. The differences between the Rotor and the Stator are that the Rotor is the rotating part of the motor, and the Stator is the stationary part of the motor. We can talk more about this another time.
Now with all these turns and kv's it's easy to get confused....
It is important to remember that different RC Vehicles have different specifications. If your RC Vehicle is large and heavy it will require more torque, meaning that a heavy 1/8 vehicle for example needs a lower kv and a higher torque motor.
With any motor choice, it is important to have the right gearing.
If you are planning to change to a completely different motor from what you have been using, remember to change the gearing at the same time - and do follow the manufactures recommendations.
Keep in mind, when choosing a higher power motor - will also shorten the runtime on one charge and produce more heat.
Make sure you do your homework before purchasing a new ESC or Motor.
Well that's it guys and gals, that's the basic information you need to hopefully guide you in the right direction when purchasing an ESC or Motor for your RC Vehicle.
We hope you find this information helpful, Happy RC-ing From the Team @ Aussie Hobbies.