ABB ACH550 User Manual page 29

E-Bypass Configurations for ACH550 Drives
contact is closed, the system is forced to bypass and does not respond to the Drive
and Bypass keys. The Automatic Transfer LED flashes green when the system is in
override. While in Bypass Override the system responds to bypass overloads, faults,
safeties and enables. Normally when the Bypass Override input contact is switched
from closed to open, the system switches to the Drive mode and can be controlled
using the Drive and Bypass keys.The exception to this is when the Fireman's
Override (Override 1) input contact is closed, in which case the system remains in
Fireman's Override mode.
Hand Mode
When the system is in the Bypass mode, the operator can manually start the motor
by pressing the Hand key on the bypass keypad. The motor will run and the Hand
LED will be illuminated green. In order to run the motor, the Safety Interlock and Run
Enable contacts must be closed (green Enable LED) and any bypass fault must be
reset.
Auto Mode
In the Auto mode the bypass start/stop command comes from the Start/Stop input
terminal on the bypass control board. The Auto mode is selected by pressing the
Auto key on the bypass keypad. The Auto LED is illuminated green when the bypass
is in the Auto mode. If the system is in the Bypass mode, the motor will run across
the line if the Auto mode is selected, the Start/Stop, Safety Interlock and Run Enable
contacts are closed and any bypass fault is reset.
Off Mode
If the motor is running in the Bypass mode, the operator can manually stop the motor
by pressing the OFF key. The Hand or Auto LED will go out. The motor can be
restarted by pressing the Hand key or the bypass can be returned to the Auto mode
by pressing the Auto key. If the system is in the Drive mode, pressing the OFF key
will take the bypass out of the Auto mode, but will not affect motor operation from the
drive. If the system is switched to the Bypass mode, a motor that is running will stop.
Bypass/Drive Mode Transfers
If the ACH550 is in the Auto mode and the motor is running in the Drive mode, the
motor will transfer to bypass operation and continue running if the system is
switched to the Bypass mode and the bypass is in the Auto mode with the Start/Stop
Input contact closed.
If the motor is running in the Bypass mode, the motor will transfer to drive operation
and continue running if the system is switched to the Drive mode and the drive is in
the Auto mode with the Start/Stop Input contact closed.
Starting the Motor on Application of Power
If the Safety Interlock and Run Enable Input contacts are closed and the system is in
the Bypass mode and in either the Hand or Auto mode, the motor will start across
the line as soon as power is applied. If the system is in the Drive mode with the drive
in the Auto mode, the motor will start on the drive as soon as power is applied.
Automatic Transfer Option
When the Automatic Transfer option is selected, the motor is automatically
transferred to line power if the drive trips out on a protective trip. If automatic restart
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Start-up