Rockwell Automation 20B PowerFlex 700 AC Drives Vector Control (v4.001 and up) - Manual (Page 141)

Rockwell Automation Publication 20B-UM002G-EN-P - July 2014 141
Application Notes Appendix C
Table 16 - Braking Method Examples
Configuration
• [Stop/Brk Mode A], parameter 155
• [Stop/Brk Mode B], parameter 156
– 0 = Coast
– 1 = Ramp
– 2 = Ramp to Hold
– 3 = DC Brake
– 4 = Fast Brake
• [DC Brk Lvl Sel], parameter 157
– 0 = “DC Brake Lvl” – selects parameter 158 as the source for the DC
brake level
– 1 = “Analog in 1”
– 2 = “Analog in 2”
• [DC Brake Level], parameter 158 – sets the DC brake level in amps, when
parameter 157 = “DC Brake Lvl”
• [DC Brake Time], parameter 159 – sets the amount of time that DC
braking is applied after the ramp (if any).
• [Flux Braking], parameter 166 – may need to adjust parameter 549
– 0 = Disabled, 1 = Enabled
• [Digital InX Sel], parameters 361…366
– 13 = “Stop Mode B” – setting a digital input to this function allows the
use of a digital input to switch between Stop Mode A (open input) and
Stop Mode B (closed input).
– 38 = “Fast Stop” – setting a digital input to this function allows the use
of a digital input to, when opened, initiate a stop with a 0.1 second
decel time. If torque proving is being used, float will be ignored at the
end of the ramp and the mechanical brake will be set.
Method Use When Application Requires… Braking Power
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).
Most, if an
external resistor
or regenerative
device is
connected.
Fast
Brake • Additional braking capability without use of an external brake resistor or regenerative
unit, but only effective during stop events, not speed changes.
Important: For this feature to function properly the active Bus Reg Mode A or B must be set
to Adjust “Freq” and NOT be “Disabled.”
More than Flux
Braking or DC
Brake
Flux
Braking In some applications, Flux Braking can provide a method for fast speed changes or stops. It is
not suitable for high inertia loads or high duty cycle operation for applications greater than 1
cycle per minute. This feature supplies additional flux current to the motor and can cause
motor thermistor or overvoltage faults in the drive.
• Fast speed changes and fast stopping time.
• Typical stop from speeds below 50% of base speed (“Flux Braking” will likely stop the load
faster than “Fast Brake” in this case).
Important: This can be used in conjunction with “Ramp” or “Ramp to Hold” for additional
braking power or with “Fast Brake” or “DC Brake” for speed changes.
Important: For this feature to function properly the active Bus Reg Mode A or B must be set
to Adjust “Freq” and NOT be “Disabled.”
More than DC
Brake
DC Brake • Additional braking capability without use of external brake resistor or regenerative units Less than above
methods