Hitachi WJ C1 Series User Manual

Chapter 9 Inverter Functions
9-5-2
9.5.2 Driving with V/f Control
 How is this used for fans, pumps, and other applications that do not require a large torque?
 How is this used for conveyors, carts, overhead cranes, and other applications that require a
certain degree of torque, regardless of speed?
 How to freely set the output voltage according to the output frequency for special motors or
applications with fluctuating loads?
 How to drive multiple motors on a single inverter?
 V/f control is a method of motor control where output voltage characteristics are set relative to
the inverter output frequency. This is an easy way to use motors when individual motor
constants for motors in use do not need to be set.
 The V/f characteristic is useful for the following types of applications.
- Applications requiring constant torque regardless of rotational speed, such as conveyors, carts,
and overhead crane runs. (Constant torque characteristics)
- Fans, pumps, and other applications that do not require a large torque at low speeds. (Reduced
torque characteristics)
- Special motors and other applications where the load varies greatly based on the rotational
speed that require the output voltage to be freely set relative to the output frequency. (Free V/f)
 Sensorless vector control is recommended for applications that require a large torque even at
low speeds, applications that require the following capability to change the output frequency
according to load variations, and applications that use simple positioning control. For details,
refer to "9.5.7 Motor Operation with Sensorless Vector Control".
Code
Item
Description
Data
[A044]
*1
Control mode selection
V/f control, Constant torque characteristics
00
V/f control, Reduced torque characteristics
01
V/f control, Free V/f
02
 Refer to "8.1 Mandatory Setting for Operation" to set the basic motor parameters before driving
the motor.
 Torque boost function can be used to adjust the torque if there is insufficient low-speed torque
while using V/f control. For details, refer to "9.5.3 Using the Torque Boost Function".
 Adjusting the " Async. motor stabilization constant [H006]
*1
" may improve an unstable motor
rotation caused by hunting or vibration. For details, refer to "9.5.6 Stabilizing Motor Hunting".
 If vibration occurs while running multiple motors on a single inverter, adjusting [H006]
*1
down
may stabilize the motors.
*1. "2nd-motor control [SET]" target parameter. The second control parameter is also subject to setting.
Q
A
!

Hitachi WJ C1 Series Specifications

General

Brand	Hitachi
Model	WJ C1 Series
Category	Inverter
Language	English