Motors
Motors convert electrical power into rotating mechanical energy. There are multiple types of motors, including brushed, brushless, and stepper motors. Most active mechanisms on FTC robots use motors to provide motion.
Motor Selection
Choosing the right motor for your application requires understanding the balance between speed, torque, power output, and gear reduction. There’s no one-size-fits-all motor—each use case demands careful matching of motor characteristics to the mechanical load.
Gearboxes: Amplifying Torque or Speed
Most FTC motors come with pre-installed gearboxes that affect output in two key ways:
High gear ratio = Low speed, High torque
Low gear ratio = High speed, Low torque
For example:
A motor with a 19.2:1 gearbox will turn slowly but provide strong torque—great for lifting heavy arms or driving slides.
A motor with a 5.2:1 gearbox spins faster with less torque—better for wheels or shooters.
Tip: Check the stall torque and free speed in the motor datasheet before deciding.
How to Calculate Torque and Speed
Motor power output is a measure of how much work the motor can do per unit time, and is defined as:
Torque vs Speed
Every motor has a performance curve. At one end is maximum torque at zero speed (stall torque), and at the other is maximum speed at zero torque (free speed). In between is the power peak—the point where the motor is doing the most work.
When designing a mechanism:
Too much torque = Slow and inefficient
Too much speed = Can’t move the load
The ideal balance happens when you operate near the motor's peak power, which is around 50% of its stall torque and 50% of its free speed.
Arm or Lift
Torque
High ratio (e.g., 19.2:1, 26:1)
Flywheel
Speed
Low ratio (e.g., 5.2:1)
Drivetrain
Balanced
Mid ratio (e.g., 13.7:1 or 20:1)
Rule of Thumb: If a motor is getting hot or stalling, you probably need more gear reduction. If it’s spinning super fast but not moving anything, increase the load or reduce gear reduction.
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