Rockwell Automation 7000A PowerFlex Medium Voltage Drive (A-Frame) - Classic Control - Manual (Page 495)

Catalog Number Explanation – Drive Selection A-5
7000 “A” Frame 7000A-UM150F-EN-P – June 2013
The PowerFlex 7000 “A” Frame drives have been tested on a
dynamometer to verify performance under locked rotor, accelerating,
and low speed-high torque conditions. Table A-5 below shows the
PowerFlex 7000 “A” Frame drive torque capabilities as a percent of
motor rated torque, independent of the drive’s momentary overload
conditions.
Table A-5
PowerFlex 7000 Drive Torque Capabilities
Parameter
7000 Torque Capability
Without Tachometer
(% of Motor Rated Torque)
7000 Torque Capability
With Tachometer
(% of Motor Rated Torque)
Breakaway Torque 90% 150%
Accelerating Torque
90% ( 0-8 Hertz ) 140% ( 0-8 Hertz )
125% ( 9-75 Hertz ) 140% ( 9-75 Hertz )
Steady State Torque 125% ( 9-75 Hertz ) **
100% ( 1-2 Hertz )
140% ( 3-60 Hertz ) **
Maximum Torque Limit 150% 150%
** Drive will require over sizing to achieve greater than 100% continuous torque.
Glossary of Terms
Breakaway Torque:
Torque required to start a machine from standstill.
Accelerating Torque:
Torque required to accelerate a load to a given speed, in a certain
period of time. The following formula may be used to calculate the
average torque to accelerate a known inertia (WK
2 ):
T = ( WK
2 
change in RPM) / 308t
where, T = acceleration torque in (lb-ft).
WK
2
= total system inertia (lb-ft 2 ) that the motor
must accelerate, including motor, gear box, and load.
t = time (seconds) to accelerate total system load.
Steady State Torque:
Continuous operating torque required to control the load, without
instability.
Torque Limit:
An electronic method of limiting the maximum torque available from
the motor.
The software in a drive typically sets the torque limit to 150% of motor
rated torque.
PowerFlex 7000
―A‖ Frame Drive
Performance
(Torque Capabilities)