ABB ACS880 Series, Application Manual, Page: 18 / 44

18 Implementing a motor thermal protection circuit

Connection diagram
The diagram below shows the connections. The system integrator must acquire the
components and do the installations drawn outside the drive border line.
1)
An ATEX-compliant protection relay. The relay monitors a sensor circuit, and activates the Safe torque off
function of the drive by opening the control circuits when necessary.
2)
You can use the drive STO function for several external safety functions at the same time (for example,
ATEX-compliant motor thermal protection, and emergency stop). If you do, you must connect the STO
activation switches or relays used in other safety functions in series with the protection relay.
3)
The STO function of the drive must always have a redundant connection. Connect the XSTO terminals 3 and
4 as shown in this figure.
4)
Connect to a digital input on the control board for the protection relay status indication. In this example,
digital input DI6 is in use.
When you install the equipment, make sure that you maintain separation of the switching (safety) signal with
any other signals.
+24 V
Control
circuit
ACS880
3 3
3~
Ex
motor
3 ~ supply
Protection relay
1)
Control
circuit
24 - 240 V AC / DC
Sensor
Potentially explosive
atmosphere
XSTO
3)
1
2
3
4
4)
2)
DI6
+24VD