Rockwell Automation 20M LPM15 Liquid-Cooled Adjustable Frequency AC Drive FRN 2.xxx User Manual
Page 123
Application Notes
D-13
Ramp to Stop
This method uses drive output reduction to stop the load.
1. On Stop, drive output will decrease according to the programmed pattern from its
present value to zero. The pattern may be linear or squared. The output will decrease
to zero at the rate determined by the programmed [Maximum Freq] and the
programmed active [Decel Time x].
2. The reduction in output can be limited by other drive factors such as such as bus or
current regulation.
3. When the output reaches zero the output is shut off.
4. The motor, if rotating, will coast from its present speed for a time that is dependent on
the mechanics of the system (inertia, friction, etc).
Ramp to Hold
This method combines two of the methods above. It uses drive output reduction to stop
the load and DC injection to hold the load at zero speed once it has stopped.
1. On Stop, drive output will decrease according to the programmed pattern from its
present value to zero. The pattern may be linear or squared. The output will decrease
to zero at the rate determined by the programmed [Maximum Freq] and the
programmed active [Decel Time x]
2. The reduction in output can be limited by other drive factors such as bus or current
regulation.
3. When the output reaches zero 3 phase drive output goes to zero (off) and the drive
outputs DC voltage on the last used phase at the level programmed in [DC Brake
Level] Par 158. This voltage causes a “holding” brake torque.
4. DC voltage to the motor continues until a Start command is reissued or the drive is
disabled.
5. If a Start command is reissued, DC Braking ceases and he drive returns to normal
AC operation. If an Enable command is removed, the drive enters a “not ready” state
until the enable is restored.
Mode
Description
DC Hold Time
DC
Hold
Level
Stop
Command
Time
Output Voltage
Output Current
Motor Speed
Output Voltage
Output Current
Zero
Command
Speed
DC
Hold Level
Time
Output Voltage
Output Voltage
Output Current
Output Current
Motor Speed
Output Voltage
Output Current
Motor Speed
Re-issuing a
Start Command
Stop
Command
Zero
Command
Speed