ABB ACS880-107

Use
1. Open the activation switch, or activate the safety functionality that is wired to
the STO connection.
2. The STO inputs on the drive control unit de-energize, and the control unit cuts off
the control voltage from the output IGBTs.
3. The control program generates an indication as defined by parameter 31.22 (see
the firmware manual of the drive).
4. The motor coasts to a stop (if running). The drive will not restart while the
activation switch or safety relay contacts are open.
5. Deactivate the STO by closing the activation switch, or resetting the safety
functionality that is wired to the STO connection.
6. Reset any faults before restarting.
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 from
the supply and all other voltage sources.
WARNING!
The Safe torque off functionality is only achieved through the XSTO connector
of the inverter control unit (A41). True Safe torque off functionality is not
achieved through the XSTO connectors of other control units (such as the
supply control unit or the brake control unit).
The Safe torque off function is supported by any ACS880 inverter or drive
control program. It is not supported by supply, DC/DC converter or brake
firmware.
WARNING!
The drive cannot detect or memorize any changes in the STO circuitry when
the drive control unit is not powered or when the main power to the drive is
off. If both STO circuits are closed and a level-type start signal is active when
the power is restored, it is possible that the drive starts without a fresh start
command. Take this into account in the risk assessment of the system.
WARNING!
Permanent magnet or synchronous reluctance [SynRM] motors only:
In case of a multiple IGBT power semiconductor failure, the drive can produce
an alignment torque which maximally rotates the motor shaft by 180/ p degrees
(with permanent magnet motors) or 180/2 p degrees (with synchronous
reluctance [SynRM] motors) regardless of the activation of the Safe torque off
function. p denotes the number of pole pairs.
Notes:
• If a running drive is stopped by using the Safe torque off function, the drive will
cut off the motor supply voltage and the motor will coast to a stop. If this causes
202 The Safe torque off function