Rockwell Automation 1336VT 5-300 AMP (2.2-160KW) - Manual (Page 27)

Overview
Chapter 3
3-11
Shown below are typical variable torque curves plotting torque versus
speed. At slow speeds, if torque requirements continuously exceed levels
shown below (10 minutes or longer), a motor rated for the required speed
and torque range must be used. To guard against mechanical problems, it
is recommended that the entire drive train machinery be checked for
various limitations due to the range of the Bulletin 1336VT.
Typical Square and Cube Law Load Curves
Torque
and
HP
25
50
75
100
125
150
25 50 75 100 125 150
Torque Horsepower
Square
Law
Loads
% Speed
Torque
and
HP
25
50
75
100
125
150
25 50 75 100 125 150
Torque Horsepower
Cube
Law
Loads
% Speed
!
ATTENTION: Motors may overheat when operated at rated
torque for long periods of time below 50% base speed due to the
decreased air flow of armature driven fans.
Motors may require special balancing if operated at more than
125% of base speed. Refer to the motor manufacturer for proper
sizing of the motor for the intended application.