ABB ACS880 Series, Инструкция по применению

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22 Implementing a motor thermal protection circuit
Protection relays
The protection relay monitors the motor equipped with temperature sensors. The sensor
indicates the motor temperature for the protection relay. For example, with a PTC
thermistor, when the motor temperature reaches the wake-up level of the sensor, the
resistance of the temperature sensor increases sharply. The relay detects the change and
indicates motor overtemperature through its output contacts. The opening contacts open
the STO circuit of the drive. This disconnects the power supply from the motor.
Use an ATEX-compliant protection relay only. The example employs an ABB CM-MSS.41
thermistor motor protection relay. You can find more information on the relay on the
Internet, for example, in the data sheet of the relay (
2CDC112216D0201 ). In this
thermistor relay, it is possible to implement a manual reset.
Include the protection relay test to the start-up and acceptance test of the motor thermal
protection circuit. See the relay manual for the relay tests.
Wiring

General wiring instructions
Wire only the sensor circuit into the potentially explosive atmosphere.
Install the drive/inverter module, the Safe torque off circuit, and the protection relay outside
the hazardous zone.
For the STO circuit wiring, use the type of cable specified in the appropriate hardware
manual.
Route the sensor cables away from the motor cable.
We recommend to use shielded sensor cable to minimize electromagnetic interference
from power cables.
Connect the control cable shields to the chassis only.
The installation must comply with the requirements of the relevant standard(s) of
EN/IEC 60079 series.
The installation of the sensor circuit in the Ex Zone must comply with the requirements for
the applicable type of protection, such as:
•
Ex d (EN/IEC 60079-1),
•
Ex eb (EN/IEC 60079-7:2015; Ex e in EN 60079-7:2007 and IEC 60079-7:2006),
•
Ex ec (EN/IEC 60079-7:2015; Ex nA in EN/IEC 60079-15:2010).

Wiring diagrams
See the appropriate section.