Rockwell Automation 7000 PowerFlex Medium Voltage AC Drive (B Frame) Commissioning - ForGe Control - Manual (Page 126)

126 Rockwell Automation Publication 7000-IN012B-EN-P - June 2014
Appendix A General Reference
PowerFlex 7000 Drive
Performance (Torque
Capabilities) The PowerFlex 7000 drives have been tested on a dynamometer to verify
performance under locked rotor, accelerating, and low speed-high torque
conditions.
Table 13 shows the PowerFlex 7000 drive torque capabilities as a
percent of motor rated torque, independent of the drive’s momentary overload
conditions.
Table 13 - PowerFlex 7000 Drive Torque Capabilities
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 x change in RPM) / 308t
where:
• T = acceleration torque in N•m (lb•ft)
• W = force N or kg f (lb)
• K = gyration radius m (ft)
• WK2 = total system inertia (kg f x m2 [lb•ft2
] ) that the motor must
accelerate, including motor, gear box, and load
• t = time (s) 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.
Parameter 7000 Torque Capability
without Encoder (% of
Motor Rated Torque) 7000 Torque Capability
with Encoder (% of
Motor Rated Torque) 7000 Torque Capability with
Encoder and High Performance
Torque Control (HPTC)
Breakaway Torque 90% 150% 150%
Accelerating Torque
90% (0...8 Hz) 140% (0...8 Hz)
150% (0...75 Hz)
125% (9...75 Hz) 140% (9...75 Hz)
Steady State Torque 125% (9...75 Hz) (1)
100% (1...2 Hz)
150% (0...60 Hz) (1)
140% (3...60 Hz)
(1)
(1) Drive will require over-sizing to achieve greater than 100% continuous torque.
Max. Torque Limit 150% 150% 150%