6. Control Functions and Parameter Settings
6-72
6-6 Application to square low variable torque load
6-6-1 Specifications for square low variable torque load
A load having characteristics in which the load torque varies with the speed, as a fan or pump, is called a
square law variable torque load. The torque curves of the constant torque load and square torque load
are shown below.
CAUTION
The variable torque specifications must be applied to square variable loads such as fans and pumps.
The constant torque specifications must be applied for all other types of loads.
S p e ed
To
rq
u
e
(fa n , p u m p)
C o n stan t to rqu e lo a d
S q u are la w va ria ble to rq ue loa d
Torque curve
The specifications for both constant torque load and square law variable torque load are shown in
Appendix 1. Hereafter, the square law variable torque load characteristics will be called the variable
torque.
