Rockwell Automation SP500 AC Drive Installation and Operation Manual - Manual (Page 118)

Glossary-2 SP500 AC Drive Installation and Operation Manual Version 3.1
overcurrent - a current greater than a specified maximum current value.
overload capacity - the ability of the drive to withstand currents beyond the system’s
continuous rating. It is normally specified as a percentage of full load current for a
specified time period.
overtemperature - a temperature greater than the specified (rated) temperature limit.
power factor - a measurement of the time phase difference between the voltage and
current in an AC circuit. Power factor is the ratio of Real Power (kW) to total KVA or the
ratio of actual power (W) to apparent power (volt-amperes).
pulse-width modulation (PWM) - a method whereby a DC voltage is converted to
produce an AC voltage whose magnitude and frequency can be varied.
rated input voltage - the specified AC line voltage connected to the drive.
rated output current - the total maximum current delivered from a drive or to a motor
under full load conditions.
rated output voltage - the drive’s total maximum output voltage while delivering rated
current under full load conditions.
rated output frequency - the fundamental output wave frequency.
rectifier - a static power converter that changes AC power to DC power.
speed range - the speed minimum and maximum at which a motor must operate
under constant or variable torque load conditions.
stall - a motor state in which the motor remains motionless although the motor is
generating torque.
surge suppressor - circuit protection that suppresses the peak value of any unusual
input voltage to the drive. It is sometimes used to lighten the leading edge of voltage.
torque - a turning force applied to a shaft, tending to cause rotation.
torque compensation - the increase of the volts/frequency ratio of the drive in the low
frequency area to compensate for the reduced torque of the motor at low speeds.
Reduced torque at low speeds is due to the resistance of the motor stator windings.
voltage feedback - a voltage signal which the regulator uses to control the operation
of the drive.
volts per hertz (V/Hz) - the ratio of output voltage (in volts) to output frequency (in
hertz) in the output frequency range of the drive to achieve constant torque in the
motor.