*
For additional assistance, please contact Toshiba Adjustable Speed Drive Marketing Dept. at (800) 872-
2192
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15
Cyclic Overhauling Load
Introduction
In applications where there is an cyclic overhauling load (such as a pumpjack, punch press, or
vibratory feeder), the motor drives the load for half the cycle and regenerates energy for the
second half of the cycle. During the regeneration cycle, the motor is turning faster than the speed
that the drive is commanding it to run. This causes power to flow in the negative direction from
the motor to the drive. This causes the DC bus capacitors to charge and reach a high voltage that
will trip the drive on overvoltage. Typically, dynamic braking resistors are employed to take the
regenerative energy and dissipate it as heat. With the G3 inverter, these resistors may no longer
be necessary because the drive can detect negative torque current and responds to it by increasing
the output frequency to eliminate regenerative current. This software is not intended for non-
cyclic regenerating loads.
Example of cyclic regenerative load
FLYWHEEL
SPRING
Stored energy
of spring
(generating)
Rotation energy
(motoring)
MOTOR
G3
This application has three parts: 1) Turn on droop and set the percent, 2) Activate the
software in Super User mode and 3) Calibrate the application.
