PTC Motor Protection Double "Isolation"?
In the ACS880, ACS580, ACQ580 manuals, there is this same recommendation for PTC wiring when hooked to DI6:
"If DI6 is used as a PTC input, the wiring and the PTC sensor need to be double isolated. Otherwise the CMOD-02 I/O extension module must be used."
What is meant by double "isolation"? Do they mean double "insulation"?
Also, if double insulation is meant, I still do not fully understand what the requirement is here and why single insulation cannot be used.
I need a full explanation please.
Voted best answer
According to IEC 60664, the connection of the motor temperature sensor requires double or reinforced insulation between motor live parts and the sensor. If the assembly does not fulfill the requirement, the I/O board terminals must be protected against contact and must not be connected to other equipment or the temperature sensor must be isolated from the I/O terminals.
For full understanding you need to read IEC 60664.