Glossary

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AC motor: A motor driven by alternating current
Armature: The component (stator or rotor) in a motor that generates the magnetic field from the supplied electric power
Armature coil: The winding that generates the magnetic field in the motor's stator or rotor

Bipolar: A technique of a stepper motor where the electrical current flows in either direction in separate coils
Brush: Component in a DC motor that is connected in series with the external power supply and reverses the electrical current through electrical contact with the commutator
Brushless motor: A DC motor that, in place of brushes and a commutator, uses a position detector or other such means to reverse the electircal current that drives the motor

Capacitor: An electronic component that stores electrical energy
Closed loop: A motor control technique that operates with the use of feedback (by monitoring the rotor position, etc.)
Commutator: A component in a DC motor that rotates along with the rotor to reverse electical current through electrical contact with the brushes
Converter: The circuit in the driver for a brushless DC motor that converts the supplied electric power from alternating to direct current
Coreless motor: A brushed DC motor with a rotor that lacks an iron core, or a brushless DC motor with a stator that lacks an iron core

DC motor: A motor driven by direct current
Detent torque (residual torque): The maximum externally applied torque needed to rotate a stepper motor with no current flow (no magnetic excitation) and open terminals

Field (magnetic field): The magnetic field generated in the motor by a permanent or electro-magnet

Holding torque (maximum stationary torque): The torque that holds a stepper motor stationary with maximum current flow when attempting to rotate the motor
Hybrid (HB) type: A stepper motor that has a set of teeth on its rotor like a VR motor, and that rotates by both reluctance torque and magnet torque
Hysteresis motor: An AC motor that uses a material in the rotor that exhibits hysteresis and that rotates by means of the hysteresis torque

Inductance: The effect that opposes or resists the change of current flow through a motor coil
Interior permanent magnet motor: A brushless motor in which permanent magnets are embedded in the interior of the rotor

Linear motor: A motor that produces liniar force rather than rotational force
Load inertia: The moment of inertia of the load or the motor itself
Loss of synchronization: The status in which a stepper motor is out of synchronization with the input pulses

Magnetic field: A region in which a magnetic force is present (directed from the north (N) to the south (S) pole of the magnet)
Maximum continuous response frequency: The maximum input pulse frequency at which a stepper motor remains synchronized when increasing its frequency under no load
Maximum self-start frequency: The maximum input pulse frequency at which a stepper motor is able to start, stop, and reverse in step syncronized with the input pulse
Mechatronics: Technology that combines mechanical and electronic engineering

Open loop: A motor control technique that operates without the use of feedback (without monitoring the rotor position, etc.)

Permanent magnet (PM) type: A stepper motor that has permanent magnets in its rotor and rotates by magnet torque alone
Permanent magnet motor: A motor that uses permanent magnets to produce magnetic field
Pull in torque: The maximum torque at which a steper motor is able to start, stop, and reverse in step syncronized with the input pulse frequency
Pull out torque: The maximum torque at which a stepper motor is able to remain synchronized when the frequency of input pulses is gradually increased after starting in the self-start range
Pulse: A short burst of electricity produced by turning the power supply on and off

Self-excited or separately excited motor: A motor that uses an electromagnet to produce magnetic field
Self-start range: The region of the motor characteristics in which a stepper motor with a fixed load is able to start, stop, and reverse in step with the input pulse frequency
Shading coil: A closed-circuit coil wound around part of the stator core
Single-phase: The conventional AC power supply typically available in homes
Sirocco fan: A fan that typically has forward curved blades and blows air perpendicular to the axis of rotation (has more blades than a turbo fan)
Slew range: The region of the motor characteristics in which a stepper motor is able to remain synchronized when the frequency or load torque are gradually increased after starting in the self-start range
Slip: The phenomenon or status whereby the speed of an AC motor is slower than its synchronous speed.
SR motor: A VR stepper motor that also has a function for detecting rotor position, which allows it to avoid loss of synchronization
Start-up torque: The maximum torque generated by the motor when starting
Stator: A stationary armature
Step angle: The angle by which a stepper motor rotates in response to a single pulse
Stepper motor (stepping motor): A motor that rotates one step at a time in response to electrical pulses
Surface permanent magnet motor: A brushless motor in which permanent magnets are attached to the circumference of the rotor

Three-phase: A form of AC power supply mainly found in industry
Torque curve (speed-torque characteristic): A curve representing the relationship between the speed of a motor and its torque and current
Turbo fan: A fan that typically has backward curved blades and blows air perpendicular to the axis of rotation (has fewer blades than a sirocco fan)

Ultrasonic motor: A motor that moves by means of ultrasonic vibrations, using friction to transform the small displacements caused by the vibrational deformation of an element into rotational or linear motion
Unipolar: A technique of a stepper motor where the electrical current flows in one direction only in separate coils
Universal motor: A motor with a wound rotor and wound stator that works with both alternating and direct current, or a brushed DC motor with an electromagnet as the stator magnet

Variable reluctance (VR) type: A stepper motor that rotates by reluctance torque alone, without using a permanent magnet

Yoke: The part of the motor's stator or rotor that forms the magnetic flux circuit from north to south pole