Motor Terminology
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Active Iron: The amount of steel (iron) in the stator and rotor of a motor. Usually the amount of active iron is increased or decreased by lengthening or shortening the rotor and stator.
Air Gap: The space between the rotating (rotor) and stationary (stator) member in an electric motor.
Air
Pressure Switch: Used on motors with blowers to measure the difference
in pressure across the filter so as to detect a clogged filter.
Air-Over (AO):
Motors for fan or blower
applications that are cooled by the air stream from the fan or blower. Motor is
located in the air stream to cool the motor.
Alternating Current (AC): Standardized power supply from local electric utility companies.
Altitude: The atmospheric
altitude (height above sea level) at which the motor will be operating; NEMA
standards call for an altitude not exceeding 3,300 ft. (1,000 meters). As the
altitude increases above 3,300 ft. and the air density decreases, the air
stability to cool the motor decreases - for higher altitudes higher grades of
insulation or a motor derating are required. DC motors require special brushes
for high altitudes.
Ambient Temperature (AMB): The temperature of the space (air) around a motor. Most motors are designed to operate in an ambient not to exceed 40C (104F).
Ampere (Amp): The standard unit of electric current. The current produced by a pressure of one volt in a circuit having a resistance of one ohm.
Anti-Friction Bearing: An anti-friction bearing is a bearing utilizing rolling elements between the stationary and rotating assemblies.
Armature: The portion of the magnetic structure of a DC or universal motor which rotates.
Axial Thrust: The force or
loads that are applied to the motor shaft in a direction parallel to the axis of
the shaft. (Such as from a fan or pump)