Cyclic Overhauling Load - Toshiba G3 Workbook

Applications workbook

Table of Contents

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.

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.

For additional assistance, please contact Toshiba Adjustable Speed Drive Marketing Dept. at (800) 872-

Cyclic Overhauling Load

Example of cyclic regenerative load

FLYWHEEL

SPRING

2192

MOTOR

Rotation energy

(motoring)

Stored energy

of spring

(generating)

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