Rockwell Automation 1557 MEDIUM VOLTAGE AC DRIVE - Manual (Page 68)

6-12 PARAMETER AND VARIABLE DESCRIPTIONS
1557-UM050F-EN-P – June 2013
Torque Limit Braking [Trq lmt braking]
Linear number:
85
Minimum value: 0.00
Maximum value: 1.50
Default value: 0.80
This parameter specifies the maximum value of the torque command when braking or generating. A value of
1.00 corresponds to rated motor torque.
Prior to Rev 4.60/5.00, this parameter was scaled in per unit based on the motor rated kVA and was about 10%
lower.
Torque Command 0 [Trq command 0]
Linear number:
86
Minimum value: 0.00
Maximum value: 1.50
Default value: 0.15
This parameter specifies the value of the torque command at zero speed used in starting mode. It may be
higher or lower than Torque Command 1. If this parameter is set too low the motor may not start. If it is set too
high the start will be excessively rough and noisy. A value of 1.00 corresponds to rated motor torque. This
parameter has no effect if the optional tach feedback is enabled.
Prior to Rev 4.60/5.00, this parameter was scaled in per unit based on the motor rated kVA and was about 10%
lower.
Torque Command 1 [Trq command 1]
Linear number:
87
Minimum value: 0.00
Maximum value: 1.50
Default value: 0.15
This parameter specifies the value of the torque command at Ramp Speed 1 and above used in starting mode.
It may be higher or lower than Torque Command 0. In starting mode, the torque command changes linearly
from Torque Command 0 at zero speed to Torque Command 1 at Ramp Speed 1. When the drive switches
from starting mode to normal running mode and the speed regulator is released, the torque command is initially
equal to the value of this parameter. If it is set too low the motor may stall before the speed regulator has time
to increase the torque command. If it is set too high, the motor will accelerate very rapidly after the transition
until the speed regulator is able to decrease the torque command to the value required to follow the speed
ramp. A value of 1.00 corresponds to rated motor torque. This parameter has no effect if the optional tach
feedback is enabled.
Prior to Rev 4.60/5.00, this parameter was scaled in per unit based on the motor rated kVA and was about 10%
lower.
Speed Reference Step [Speed ref step]
Linear number:
88
Minimum value: 0.0 Hz
Maximum value: 2.0 Hz
Default value: 0.0 Hz
This parameter specifies the magnitude of the step that is added to the speed error to demonstrate the step
response of the speed loop. It is not saved and is initialized to zero at power up.