ABB ACS880 Series User Manual page 18

18 ATEX-certified motor thermal protection function with PTC thermistor relays (+L513+Q971)
ACS880-07 drives (frames n×DxT + n×R8i) with a main contactor/breaker (option
+F250/+F255), ACS880-17/37 drives (frames n×R8i + n×R8i) and ACS880-17LC/37LC
drives (frames n×R8i + n×R8i): When the STO function is activated in the inverter unit, the
main contactor/breaker is opened after user-defined delay (defined with parameter 94.11,
the default value is 600 s). See hardware and firmware manuals for more information.
Other safety functions in the drive can also use the STO function. Also, an FSO module can
be included in the ATEX-certified motor thermal protection function. See the circuit diagrams
delivered with the drive for the actual safety circuitry.
The FSO safety functions module (FSO-12 or FSO-21) is an optional device used with the
ACS880 drives to implement safety functions. When installed, it reserves the standard STO
connection of the drive.
The motor thermal protection function is implemented as follows:
• without an FSO module, the opening contacts of the relay(s) open the STO circuit of
the drive.
• with an FSO module, the opening contacts of the relay(s) activate the STO or Safe stop
1 (SS1) function of the FSO module, and the FSO module opens the STO circuit of the
drive.
Select the stop category according to the system risk assessment.
The protection function circuit is motor-specific. The function stops only the motor where
overtemperature is detected.
It is possible to get information on the status of the protection function through a
normally-open contact of the relay. The information can be obtained separately from the
bearing and stator sensors. The contact can be wired to a digital input on the drive control
unit or to an external control system. See the wiring instructions.