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Category: Motors

Electric Motor Terminology

Electric motors are complex. There are several different kinds, and they have many working parts. If you've ever wanted to learn more about how a motor works, here is some helpful basic electric motor terminology to know.

Ampere: Standard unit of measurement for electric currents. In a circuit, a force of one volt equates to a resistance ratio of one ohm and one ampere.

Back-EMF: An electromotive force produced when a conductor moves through a magnetic field. Generated when the armature is moving, regardless of whether or not the motor has power.

Brushed DC motor: A type of electric motor that runs from a direct power source.

Capacitator: A small device in the engine that contains electrical energy.

Converter: Refers to the process of changing alternating current (AC) electricity to direct current (DC) electricity.

Curie temperature: Characteristic of ferromagnetic materials. Used as a point of reference to assess magnet potential and monitor temperature rise.

Current: The movement of electrons (usually from positive to negative) through conducting materials. Measured in amperes.

Direct drive: Drives that send power directly to an application rather than going through gears or another method of power transfer.

Eddy current: Induces circulating currents with alternating magnetic flux.

Efficiency: The input to output ratio, or the effectiveness of converting energy.

EMF: An acronym used to explain motor design in the context of electromotive force.

Field of the stator: Electromagnetic field in a motor that changes the magnetic field to an electric current. Determines fluid flow in fluid-powered devices.

Induction motor: Also called an asynchronous motor. Uses alternating current AC to create torque through electromagnetic induction.

Inverter: An electronic component that turns power supplied to a motor from DC voltage into AC voltage.

Locked rotor: Current produced by a motor at its rated voltage when the motor is not moving. A locked rotor can also occur when an engine reaches maximal torque but still has a torque load requirement that exceeds the pull out torque.

Magnetic bearing speed sensor: Also called the “speed sensor.” Measures the rotational speed of a shaft spinning on its axis.

Motor shaft: Also called a drive shaft or propeller shaft. Connects different parts of a drivetrain that can't be connected directly.

Motor winding: Used to generate force in an electric motor. Power is produced through an interaction between the electrical current in the wire winding and the magnetic field of the engine.

Neodymium magnet: Permanent magnet with neodymium.

Permeability: Measures ease of magnetic field flow.

Resolver: Electromagnetic feedback mechanism that converts angular shaft position to analog signals.

Samarium magnet: Permanent magnet with samarium cobalt.

Single phase motor: Simplest electric motor design with minimal power output – usually only around one horsepower (HP). Electric motors also come in two phase and three phase designs.

Stepper motor: A brushless DC motor with a full rotation divided into equal steps. Stepper motors come in various phases.

Synchronous motor: An AC motor with a shaft that rotates in sync with the supply current's frequency.

PMSM motor: An AC electric motor with a rotor magnetic field produced by permanent magnets instead of electromagnets. The stator windings of a brushless AC motor are sinusoidally distributed.

Power density: A motor's power to weight ratio.

Power factor: Ratio of real power (called “W”) to apparent power (“VA”). In AC systems, refers to the difference in measurement between current and voltage.

Power source: Source of power for a motor. Examples are electric-powered and battery-powered motors.

Variable speed drive: Also called “drive” or “variable frequency drive.” Electronically controls torque, speed, and horsepower of an AC or a DC motor.

Understanding electric motor terminology is useful for understanding how your car or other motor-powered devices operate. It can also help you learn motor anatomy and perhaps even identify and solve your own motor problems. See all of our repair services here, and be sure to fill out a quote today to get your motors worked on!