ABB ACS800 Firmware Manual page 189

Index Name/Selection
THERMISTOR
Description
Motor thermal protection is activated through digital input DI6. A motor
thermistor, or a break contact of a thermistor relay, must be connected to digital
input DI6. The drive reads the DI6 states as follows:
DI6 Status (Thermistor resistance)
1 (0 ... 1.5 kohm)
0 (4 kohm or higher)
WARNING! According to IEC 664, the connection of the motor
thermistor to the digital input requires double or reinforced insulation
between motor live parts and the thermistor. Reinforced insulation
entails a clearance and creeping distance of 8 mm (400 / 500 V AC
equipment). If the thermistor assembly does not fulfil the requirement, the other
I/O terminals of the drive must be protected against contact, or a thermistor
relay must be used to isolate the thermistor from the digital input.
WARNING! Digital input DI6 may be selected for another use. Change
these settings before selecting THERMISTOR. In other words, ensure
that digital input DI6 is not selected with any other parameter.
The figure below shows the alternative thermistor connections. At the motor
end the cable shield should be earthed through a 10 nF capacitor. If this is not
possible, the shield is to be left unconnected.
Alternative 1
Thermistor
relay
T
Motor
Alternative 2
T
10 nF
Motor
Temperature
Normal
Overtemperature
RMIO board, X22
6 DI6
7 +24 V DC
RMIO board, X22
6 DI6
7 +24 V DC
Actual signals and parameters
189
FbEq
3