What are they?
An “Electronic Speed Controller” or ESC is any device that is designed to receive control signals (typically from your bot’s radio receiver) and use them to move electric motors. Below is a simple diagram to illustrate where these components fit in your bot design:
In this section, we will review the most common categories of speed controllers available and how they can be used in your bot construction.
Types of ESC’s
There are many different types of ESC’s and even more opinions about the “best” one to use. To start your own ESC journey, first understand the type and number of motors your bot will use in your design.
You only need ESC’s designed for the motors you will use. (See the Electric Motors section for information on motor types and selection)
- Brushed Motor ESC’s: If you are using brushed DC motors, you will need at least one ESC designed specifically to control brushed DC motors. This is most commonly used for your bot’s drive system.
- Brushless Motor ESC’s: If you are using brushless DC motors, you will need at least one ESC designed specifically to control brushless DC motors. This is most commonly used for your bot’s weapon system but can also be used for drive system.
How to attach the ESC’s to the receiver and motors
Brushed Motor ESC’s
Typically, a brushed ESC will control either one or two brushed motors. (Remember, brushed motors have 2 wires for power connection.)
Below is an example of a brushed motor ESC. This Sabertooth Dual 12A 6V-24V R/C Regenerative Motor Driver is designed to control 2 motors at the same time. (This is why it’s called a dual motor driver.)
This ESC will be connected in 6 different places.
- 1 connection to the battery. (Supplies power to the ESC circuits, motors, and the RC receiver.)
- 2 connections to the motors. (In this case, the ESC is a dual-controller so power wires (positive and negative) run from the ESC to each motor.)
- 3 connections to the RC receiver. (This type of ESC uses 3 “channels” from your receiver to control the speed and direction of your 2 motors.)
- One controls left/right commands.
- One controls forwards/backwards commands.
- One is optional, and allows you to send a signal that the bot has been “flipped over”. If that happens, the “flip channel” will reverse your commands so you can drive upside down without having to change how you operate the RC transmitter. (In short, forward on the control stick will still mean forward to the bot in the arena. Left will mean left, right will mean right, etc.)
Brushless Motor ESC’s
Typically, a brushless ESC will control one brushless motor. (Remember, brushless motors have 3 wires for power connection.)
Below is an example of a brushless motor ESC. This specific model came in a bundle purchase on Amazon including a brushless motor; costing $14.
This ESC will be connected in 3 different places to control 1 motor.
- 1 connection to the battery. (Supplies power to the ESC circuits, motors, and the RC receiver. These are the thick red and black wires in the picture above.)
- 1 connection to the motor. (These are the 3 blue wires in the picture above. Remember, a brushless motor requires 3 wires from the ESC to the motor. A brushed motor only requires 2.)
- 1 connection to the RC receiver: This controls the speed of your motor as well as the “on/off” function.
- For example, if you were using a brushless motor and this ESC to control a weapon, then you would connect it to it’s own channel on the RC receiver.
- Ideally, you would use the channel normally used for “throttle” in the RC control settings. This way you can turn the motor on and off in the middle of the fight without having to continuously press a button or joystick. “Set it and forget it”. (see the image below)