Hitachi SJ100 Series Instruction Manual page 7

A–6
Glossary
Rectifier
Regenerative Braking
Regulation
Reverse Torque
Rotor
Saturation Voltage
Sensorless Vector
Control
Setpoint (SP)
Single-phase
Slip
Squirrel Cage
An electronic device made of one or more diodes which converts
AC power into DC power. Rectifiers are usually used in combina-
tion with capacitors to filter (smooth) the rectified waveform to
closely approximate a pure DC voltage source.
A particular method of generating reverse torque to a motor, an
inverter will switch internally to allow the motor to become a gener-
ator and will store the energy internally and/or deliver the braking
energy back to the power input mains.
The quality of control applied to maintain a parameter of interest at
a desired value. Usually expressed as a percent (+/-) from the
nominal, motor regulation usually refers to its shaft speed.
The force of available from some types of inverters to change the
direction of rotation of a motor shaft. As such, reverse torque is a
decelerating force on the motor and its external load.
The windings of a motor that rotate, being physically coupled to the
motor shaft. See also stator.
For a transistor semiconductor device, it is in saturation when an
increase in input (gate) current no longer results in an increase in
the output (source/drain) current. The saturation voltage is the
voltage from the power source to the transistor output (Vsource to
Vdrain). The ideal saturation voltage is zero.
A technique used in variable-frequency drives to rotate the force
vector in the motor without the use of a shaft position sensor
(angular). Benefits include an increase in torque at the lowest speed
and the cost savings from the lack of a shaft position sensor.
The setpoint is the desired value of a process variable of interest.
See also Process Variable (PV) and PID Loop.
An AC power source consisting of Hot and Neutral wires. An Earth
Ground connection usually accompanies them. In theory, the
voltage potential on Neutral stays at or near Earth Ground, while
Hot varies sinusoidally above and below Neutral. This power source
is named Single Phase to differentiate it from three-phase power
sources. Some Hitachi inverters can accept single phase input
power, but they all output three-phase power to the motor. See also
three-phase.
The difference between the theoretical speed of a motor at no load
(determined by its inverter output waveforms) and the actual speed.
Some slip is essential in order to develop torque to the load, but too
much will cause excessive heat in the motor windings and/or cause
the motor to stall.
A "nick-name" for the appearance of the rotor frame assembly for
an AC induction motor.