Rockwell Automation 20B PowerFlex 700 AC Drives Vector Control (v4.001 and up) - Manual (Page 140)

140 Rockwell Automation Publication 20B-UM002G-EN-P - July 2014
Appendix C Application Notes
Start At PowerUp A powerup delay time of up to 30 seconds can be programmed through [Powerup
Delay], parameter 167. After the time expires, the drive will start if all of the start
permissive conditions are met. Before that time, restart is not possible.
Stop Mode The PowerFlex 700 offers several methods for stopping a load. The method/
mode is defined by [Stop/Brk Mode A/B], parameters 155 and 156. These
modes include:
• Coast
• Ramp
• Ramp to Hold
• DC Brake
• Fast Brake
Additionally, [Flux Braking], parameter 166 can be selected separately to provide
additional 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 (that is, 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 16 describes several braking capability examples.
[Powerup Delay]
Time Expired?
Start At PowerUp
Yes
Powerup Terminated!
Normal Mode
No
No
No
Powerup Start
Is the terminal block Run,
Run Forward or Run Reverse
Input Closed?
Yes
Yes
All Start Permissives Met?
1. No fault conditions present.
2. No Type 2 alarm conditions present.
3. The terminal block programmed
enable input is closed.
4. The Stop input (from all sources) is
received.