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Prevention of unexpected start-up (option +Q950)
The drive can have an optional Prevention of unexpected start-up function according
to standards:
•
IEC/EN 60204-1:1997
•
ISO/DIS 14118:2000
•
EN 1037:1996
•
EN ISO 12100:2003
•
EN 954-1:1996
•
EN ISO 13849-2:2003
The Prevention of unexpected start-up (POUS) function disables the control voltage
of the power semiconductors, thus preventing the drive from generating the AC
voltage required to rotate the motor. By using this function, short-time operations
(like cleaning) and/or maintenance work on non-electrical parts of the machinery
can be done without switching off the AC power supply to the drive.
The operator activates the Prevention of unexpected start-up function by opening a
switch on a control desk. An indicating lamp on the control desk comes on to
indicate that the prevention of unexpected start-up is active. The switch can be
locked out.
The user must install on a control desk near the machinery:
•
switching/disconnecting device for the circuitry. "Means shall be provided to
prevent inadvertent, and/or mistaken closure of the disconnecting device."
EN 60204-1:1997.
•
indicating lamp: on = starting the drive is prevented, off = drive is operative.
For connections to the drive, see the circuit diagram delivered with the drive.
WARNING! The Prevention of unexpected start-up function does not
disconnect the voltage of the main and auxiliary circuits from the drive.
Therefore maintenance work on electrical parts of the drive or the motor
can only be carried out after isolating the drive system from the main
supply.
Note: The Prevention of unexpected start-up function is not intended for stopping
the drive. If the Prevention of unexpected start-up function is activated when the
drive is running, the control voltage of the inverter power semiconductors is cut off
and the motor coasts to a stop.
For detailed instructions for installation, start-up, use and maintenance of the
Installation of the AGPS board (Prevention of unexpected start-up,
function, see
+Q950)
(page 83).
Planning the electrical installation 57
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