32 Rockwell Automation Publication 6000-TD004D-EN-P - November 2017
Chapter 1 Functional Descriptions
Automatically Switch to Bypass
This function allows the drive to automatically switch to the frequency bypass
when a fault occurs.
To enable this function, set Bypass Mode Selection (P484) to “2”, and set Fault-To-
Bypass (P471) to “1”. At this time, the drive will force the setting of Motor
Rotation Direction Under Local Control (P008) to “1” and Motor Rotation
Direction Command Selection (P009) to “0”. This is done to prevent the drive
from running in a reverse direction.
The drive will automatically switch to the frequency bypass when a fault occurs
and the fault duration exceeds the value set in Fault-To-Bypass Delay (P472).
Bypass to VFD
This function is used to switch the motor running mode from the frequency
bypass to the drive.
During automatic bypass, one-drive-one motor, make sure the “Drive - Frequency
Bypass” switch is in the “Drive” position. When the Bypass to VFD function is
enabled, the motor is automatically switched from the frequency bypass to the
drive operation. The controller disconnects the frequency bypass contactor,
closes the drive connector, and starts the drive.
When clicking the Bypass to VFD button, the control logic is as follows:
1. The controller saves the current value of Flying Start Mode (P416) and
Restart Enable (P461).
2. The controller forces the setting of Motor Rotation Direction Under Local
Control (P008) to “1” and Motor Rotation Direction Command Selection
(P009) to “0”.
3. The controller disconnects the frequency bypass contactor and closes the
drive connector.
4. The controller changes the value of Flying Start Mode to “3” and Restart
Enable to “0”.
The drive will not switch to the frequency bypass in the following conditions:
• When a trip signal is issued.
• When the drive is stopping.
• During an emergency stop.
• The frequency is less than the value set in Fault-To-Bypass Minimum
Frequecy, Zero through Rated Frequency (P474).
• When the time to start the drive is less than the value set in Fault-To-
Bypass Delay When Starting The Motor (P473).
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