Rockwell Automation Liqui-Flo DBT Reach Drive - Manual (Page 231)

Application Notes Appendix D-17
Additionally, Flux Braking (166) can be selected separately to provide addtional
braking during a “Stop” command or when reducing the speed command. For “Stop”
commands, this will provide additional braking power during “Ramp” or “Ramp to
Hold” selections only. If “Fast Brake” or “DC Brake” is used, “Flux Braking” will only be
active during speed changes (if enabled).
A “Ramp” selection will always provide the fastest stopping time if a method to
dissipate the required energy from the DC bus is provided (i.e. resistor brake,
regenerative brake, etc.). The alternative braking methods to external brake
requirements can be enabled if the stopping time is not as restrictive. Each of these
methods will dissipate energy in the motor (use care to avoid motor overheating).
Table D.3 describles several braking capability examples.
Table D.3 – Braking Method Examples
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
may result in excessive motor
heating).
Most
Fast Brake • Additional braking capability without
the use of external brake resistor or
regenerative units. More than Flux
Braking or DC Brake
Flux Braking • 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.)
More than DC Brake
DC Brake • Additional braking capability without
the use of external brake resistor or
regenerative units. Less than above
methods