ABB DriveIT ACH550-01 User Manual page 260

Warning! IEC 60664 requires double or reinforced
insulation between live parts and the surface of accessible
parts of electrical equipment which are either non-
conductive or conductive but not connected to the
protective earth.
To fulfil this requirement, connect a thermistor (and other
similar components) to the drive's control terminals using
any of these alternatives:
• Separate the thermistor from live parts of the motor with
double reinforced insulation.
• Protect all circuits connected to the drive's digital and
analog inputs. Protect against contact, and insulate from
other low voltage circuits with basic insulation (rated for
the same voltage level as the drive's main circuit).
• Use an external thermistor relay. The relay insulation
must be rated for the same voltage level as the drive's
main circuit.
The figure below shows alternate thermistor connections. At the
motor end the cable shield should be earthed through a 10 nF
capacitor. If this is not possible, leave the shield unconnected.
Thermistor
relay
256
T
Motor
ACH550 User's Manual
I/O board
DI
+24 VDC
Parameter listing and descriptions