Product Manual

Thermistors: Are conductive ceramic materials, whose resistance remains
relatively constant over a broad temperature range, then changes abruptly
at a design threshold point, creating essentially a solid-state thermal switch.
Attached control modules register this abrupt resistance change and
produce an amplified output signal, usually a contact closure or fault
trip annunciation. Thermistors are more accurate and faster responding
than thermostats.
Thermostat: A protector, which is temperature-sensing only, that is
mounted on the stator winding. Two leads from the device must be
connected to a control circuit, which initiates corrective action. The
customer must specify if the thermostats are to be normally closed or
normally open.
Thermocouple: A pair of dissimilar conductors joined to produce a
thermoelectric effect and used to accurately determine temperature.
Thermocouples are used in laboratory testing of motors to determine
the internal temperature of the motor winding.
Thrust Load: Force imposed on a shaft parallel to a shaft’s axis. Thrust
loads are often induced by the driven machine. Be sure the thrust load
rating of a gear reducer is sufficient so that its shafts and bearings can
absorb the load without premature failure.
Torque: The turning effort or force applied to a shaft, usually expressed
in inch-pounds or inch-ounces for fractional and sub-fractional HP
motors.
Starting Torque: Force produced by a motor as it begins to turn from
standstill and accelerate (sometimes called locked rotor torque).
Full-Load Torque: The force produced by a motor running at rated
full-load speed at rated horsepower.
Breakdown Torque: The maximum torque a motor will develop
under increasing load conditions without an abrupt drop in speed
and power. Sometimes called pull-out torque.
Pull-Up Torque: The minimum torque delivered by a motor between
zero and the rated RPM, equal to the maximum load a motor can
accelerate to rated RPM.
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