Implementing The Safe Torque Off Function; Implementing The Power-Loss Ride-Through Function; Supplying Power For The Auxiliary Circuits - ABB ACS800-17LC Hardware Manual

Implementing the Safe torque off function

Safe torque off with safety relay option (+Q968) is available for the drive. It provides
Safe torque off (STO) function according to standards EN 61800-5-2:2007; EN ISO
13849-1:2008, IEC 61508 and EN 62061:2005. The function also corresponds to an
uncontrolled stop in accordance with stop category 0 of EN 60204-1 and prevention
of unexpected start-up of EN 1037.
The Safe torque off function disables the control voltage of the power
semiconductors of the drive output stage, thus preventing the inverter from
generating the voltage required to rotate the motor (see diagram below). By using
this function, short-time operations (like cleaning) and/or maintenance work on non-
electrical parts of the machinery can be performed without switching off the power
supply to the drive.
WARNING! The Safe torque off 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: It is not recommended to stop the drive by using the Safe torque off function. If
a running drive is stopped by using the Safe torque off function, the drive will stop by
coasting. If this causes danger or is not acceptable, the drive and machinery must be
stopped using the appropriate stopping mode before using the Safe torque off
function.
Note concerning permanent magnet motor drives in case of a multiple IGBT
power semiconductor failure: In spite of the activation of the Safe torque off
function, the drive system can produce an alignment torque which maximally rotates
the motor shaft by 180/p degrees. p denotes the pole pair number.
For more information, see Wiring, start-up and operation instructions of safety
options (+Q950, +Q951, +Q952, +Q963, +Q964, +Q967 and +Q968) for ACS800
cabinet-installed drives (3AUA0000026238 [English]).

Implementing the power-loss ride-through function

The power loss ride-through is not available as an standard option (on the price list).
However, the supply unit control program supports the function, and it can be
implemented in most cases if ordered separately as an engineered option for the
delivery.

Supplying power for the auxiliary circuits

Drives of frame sizes R7i+R7i and R8i+R8i are equipped with an auxiliary control
voltage transformer which supplies 230 V AC voltage to cooling fans and control
circuits. With option +G304 the supplied voltage is 115 V AC.
Planning the electrical installation
85