Operating Modes - ABB ACH 400 User Manual

Chapter 2 – Overview of ACH 400 with Electronic Bypass
Hand LED
Auto LED
Automatic LED
Auto Key
Reset Key
Drive Select Key
Bypass Select Key
Hand Key
OFF Key

Operating Modes

Drive mode
Bypass mode
Hand mode
2-6
The Hand LED is illuminated green when the motor has been started
manually in the bypass mode.
The Auto LED is illuminated green when the Auto Start contact has been
selected as the means for starting and stopping the motor in the bypass mode.
The Automatic LED is illuminated green when the Automatic Transfer to
Bypass feature has been selected.
The Auto key selects the Auto Start contact as the means for starting and
stopping the motor in the bypass mode.
The Reset key resets the bypass fault.
The Drive Select key selects the ACH 400 drive as the power source for the
motor.
The Bypass Select key selects the bypass as the power source for the motor.
The Hand key can be used to manually start the motor when the bypass has
been selected as the power source for the motor.
The OFF key can be used to manually stop the motor if the motor has been
running on bypass power.
Under normal conditions the bypass is in the Drive mode. The ACH 400 drive
provides power to the motor and controls its speed. The source of the drive's
start/stop and speed commands is determined by the Auto or Hand mode
selection of the drive's keypad. Commands come from the control terminals
when the Auto mode has been selected or from the drive keypad when the
Hand mode has been selected.
In the Bypass mode, the motor is powered by AC line power through the
bypass contactor. The user can switch to the Bypass mode by pressing the
Bypass key on the bypass keypad or by closing the Mode input contact. If the
Mode input contact is closed, the bypass switches to the Bypass mode and
does not respond to the Drive and Bypass keys. When the Mode input contact
is switched from closed to open, the bypass switches to the Drive mode but
can be controlled using the Drive and Bypass keys. Switching to Bypass mode
is done automatically if the user has selected the Automatic Transfer option
and a drive fault occurs.
The source of the bypass start/stop command is determined by the Hand or
Auto mode selection of the bypass keypad. Refer to the following descriptions
of the Hand mode and Auto mode.
When the bypass is in the Bypass mode, the operator can manually start the
motor by pressing the Hand key. The motor will start and the Hand LED will
be illuminated green. In order to start the motor, the Enable contact must be
closed (green Enable LED) and any bypass fault must be reset.
ACH 400 with Electronic Bypass User's Manual