Rockwell Automation 20G PowerFlex 750-Series AC Drives - Manual (Page 97)

Rockwell Automation Publication 750-RM002B-EN-P - September 2013 97
Drive Configuration Chapter 1
Braking Methods
Coast
Coast is selected by setting P370/371 [Stop Mode A/B] to 0 “Coast.” When in
Coast to Stop, the drive acknowledges the Stop command by shutting off the
output and releasing control of the motor. The load/motor will coast or free spin
until the kinetic energy is dissipated.
• On Stop, the drive output goes immediately to zero (off ).
• No further power is supplied to the motor. The drive has released control.
• The motor coasts for a time that is dependent on the mechanics of the
system (Inertia, friction, and so forth).
Method Use when application Requires Braking Power
Coast Power is removed from the motor and it coasts to zero speed None
Ramp The fastest stopping time or fastest ramp time for speed changes (external
brake resistor or regenerative capability required for ramp times faster than
the methods below). High duty cycles, frequent stops or speed changes. (The
other methods can result in excessive motor heating). The most
Ramp to Hold Same as ramp above only when zero speed is reach the drive outputs a DC
brake current to be sure the motor shaft doesn't move after it has stopped.
This continues until the drive is started again. Same as “Ramp”
DC Brake DC braking is immediately applied (does not follow programmed decel ramp).
May have to adjust P397 [DC Brake Kp]. Less than Ramp or
Fast Brake
DCBrkAutoOff Applies DC braking until zero speed is reached or DC brake time is reached,
whichever is shorter. Less than Ramp or
Fast Brake
Current Lmt Max torque / current applied until zero speed Big Stuff
Fast Brake High slip braking for maximum braking performance above base speed. More than DC
Brake / DC Brake
Auto Off
Bus Voltage
Output Voltage
Output Current
Motor Speed
Command Speed
Time
Coast Time is load dependent Stop Command