Product Manual

Service Factor for Motors: A measure of the overload capacity built
into a motor. A 1.15 SF means the motor can deliver 15% more than the
rated horsepower without injurious overheating. A 1.0 SF motor should
not be loaded beyond its rated horsepower. Service factors will vary for
different horsepower motors and for different speeds.
Short Circuit: A fault or defect in a winding causing part of the normal
electrical circuit to be bypassed, frequently resulting in overheating of
the winding and burnout.
Slip: (1) The difference between rotating magnetic field speed
(synchronous speed) and rotor speed of AC induction motors. Usually
expressed as a percentage of synchronous speed. (2) The difference
between the speed of the rotating magnetic field (which is always
synchronous) and the rotor in a non-synchronous induction motor is know
as slip and is expressed as a percentage of a synchronous speed. Slip
generally increases with an increase in torque.
Speed Regulation: In adjustable speed drive systems, speed regulation
measures the motor and control’s ability to maintain a constant preset
speed despite changes in load from zero to 100%. It is expressed as a
percentage of the drive system’s rated full load speed.
Stator: The fixed part of an AC motor, consisting of copper windings
within steel laminations.
Temperature Rise: The amount by which a motor, operating under
rated conditions, is hotter than its surrounding ambient temperature.
Temperature Tests: These determine the temperature of certain parts
of a motor, above the ambient temperature, while operating under
specific environmental conditions.
Thermal Protector: A device, sensitive to current and heat, which
protects the motor against overheating due to overload or failure to
start. Basic types include automatic rest, manual reset and resistance
temperature detectors.
Thermal Rating: The power or torque a gear reducer can transmit
continuously. This rating is based upon the reducer’s ability to dissipate
the heat caused by friction.
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