Rockwell Automation 7000A PowerFlex Medium Voltage AC Drive - Air-Cooled (A Frame) - Manual (Page 381)

Catalog Number Explanation – Drive Selection A-5
7000 “A” Frame 7000A-RM001A-EN-P – January 2011
The PowerFlex 7000 drives have been tested on a dynamometer to
verify performance under locked rotor, accelerating, and low speed-
high torque conditions. Table A-4 below shows the PowerFlex 7000
drive torque capabilities as a percent of motor rated torque, independent
of the drive’s momentary overload conditions.
Table A-4 – 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%
90% ( 0-8 Hertz ) 140% ( 0-8 Hertz )
Accelerating Torque
125% ( 9-75 Hertz ) 140% ( 9-75 Hertz )
100% ( 1-2 Hertz )
Steady State Torque 125% ( 9-75 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
Performance
(Torque Capabilities)