Understanding Motor Specifications
Motors are rated by their voltage, current draw, output speed, and torque.
Operating Voltage
Operating voltage specifies the nominal (normal) voltage the manufacturer recommends for the motor. Most small DC motors are designed for 1.5 to 12 volt operation, with the majority in the 3-6 volt range. Larger DC motors designed for heavy-duty applications usually require 12 to 24 volts, with some needing upwards of 90 volts. Often, but not always, the higher the voltage, the more powerful the motor (this does not apply to stepper motors, where very low voltages — on the order of just a few volts — are common for heavy-duty motors). Most motors can be run at operating voltages higher or lower than the specified rating.
- Lower voltages reduce torque and speed.
- Higher voltages increase torque and speed.
(Note: For stepper motors, speed is not greatly altered by changing the voltage.)