Synchronous motors (PMSM) – Manual with installation instructions
22
B 5000 en-2621
2.4.6 Interference emission and resistance to interference
NORD motors comply with the EU Directive 2014/30/EU. Assembly or installation work must not
cause impermissible interference emissions. Resistance to interference must still be given.
Interference emissions
Great differences of torque (e.g. when driving a piston compressor) induce a non-sine wave motor
current, whose harmonics can cause an impermissible effect on the mains and therefore
impermissible interference emissions.
With supply by frequency inverters, various strengths of interference are produced according to the
design of the frequency inverter (type, interference suppression, manufacturer).
Always observe the EMC information provided by the inverter manufacturer. If a shielded motor supply
cable is recommended by the manufacturer, the shielding is most effective if a large area is electrically
connected to the metal terminal box of the motor (with a metal EMC cable gland).
For motors with integrated sensors (e.g. thermistors) interference voltages due to the inverter may be
produced in the sensor cables.
Resistance to interference
For motors with integrated sensors (e.g. thermistors) the operator must ensure adequate immunity to
interference by the selection of a suitable sensor cable (possibly with screening, with connection as for
the motor supply cable) and evaluation device.
Before commissioning, observe the information and instructions given in the operating instructions for
the inverter and all other instructions.
