Planning the electrical installation45Prevention of Unexpected StartThe ACS800-01/U1, ACS800-04/U4, ACS800-11/U11, ACS800-31/U31 andACS800-07/U7 can be equipped with an optional Prevention of Unexpected Startfunction according to standards IEC/EN 60204-1: 1997; ISO/DIS 14118: 2000 andEN 1037: 1996.The Prevention of Unexpected Start function disables the control voltage of thepower semiconductors, thus preventing the inverter from generating the AC voltagerequired to rotate the motor. By using this function, short-time operations (likecleaning) and/or maintenance work on non-electrical parts of the machinery can beperformed without switching off the AC power supply to the drive.The operator activates the Prevention of Unexpected Start function by opening aswitch on a control desk. An indicating lamp on the control desk will light, signallingthat the prevention is active. The switch can be locked out.The user must install on a control desk near the machinery:ï switching/disconnecting device for the circuitry. ìMeans shall be provided toprevent inadvertent, and/or mistaken closure of the disconnecting device.îEN 60204-1: 1997.ï indicating lamp; on = starting the drive is prevented, off = drive is operative.ï ACS800-01/U1, ACS800-04/U4, ACS800-11/U11, ACS800-31/U31: safety relay(type BD5935 has been approved by ABB)For connections to the drive, see chapter Installation of AGPS board (Prevention ofUnexpedted Start, +Q950) or the circuit diagram delivered with the drive (ACS800-07/U7).WARNING! The Prevention of Unexpected Start function does not disconnect thevoltage of the main and auxiliary circuits from the drive. Therefore maintenance workon electrical parts of the drive or the motor can only be carried out after isolating thedrive system from the main supply.Note: If a running drive is stopped by using the Prevention of Unexpected Startfunction, the drive will cut off the motor supply voltage and the motor will coast tostop.
