Prevention Of Unexpected Start - ABB ACS800-37-0060-3 Hardware Manual

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Prevention of unexpected start

The drive can be equipped with an optional prevention of unexpected start function
according to standards IEC/EN 60204-1: 1997; ISO/DIS 14118: 1996 and EN 1037:
1996. The circuit conforms to EN954-1, Category 3.
The function is achieved by disconnecting the control voltage to the power
semiconductors of the inverters of the drive. Thus it is not possible for the power
semiconductors to switch and generate the AC voltage needed to rotate the motor.
In case of faulty main circuit components, the DC voltage from the busbars can be
conducted to the motor but an AC motor cannot rotate without the field generated by
an AC voltage.
The operator activates the prevention of unexpected start function using a switch
mounted on a control desk. When the function is activated, the switch is opened, and
an indicator lamp will light.
WARNING! The prevention of unexpected start function does not disconnect the
voltage of the main and auxiliary circuits from the drive. Therefore maintenance work
on electrical parts of the drive can only be carried out after isolating the drive system
from the main supply.
Note: The prevention of unexpected start function is not intended for stopping the
drive. If a running drive is stopped by using the prevention of unexpected start
function, the drive will cut off the motor supply voltage and the motor will coast to
stop.
Planning the electrical installation