Patent ID: 11898917
Assignee: SIEMENS AKTIENGESELLSCHAFT
Field: Measurement (Instruments)
Classification: CPC G  H | IPC G  H

Claim 11:
12. A drive, comprising:
a dynamoelectric machine including a multiphase winding;
a multiphase AC/AC converter powering the dynamoelectric machine; and
an apparatus for monitoring a winding temperature of the multiphase winding of the dynamoelectric machine, said apparatus configured to:
determine electrical power applied from an output of the multiphase AC/AC converter to the multiphase winding of the electric machine,
determine a heating power dissipated by the multiphase winding from a product of output voltages and output currents measured for each phase at the multiphase AC/AC converter after subtracting from the electrical power a mechanical power generated by the electric machine;
determine a relative increase in a resistance of the multiphase winding caused by the dissipated heating power, when the winding heats up, in comparison with a reference resistance value at a reference winding temperature;
calculate the winding temperature from the relative increase in the resistance of the multiphase winding, using a known temperature dependence of the resistance of the multiphase winding; and
generate a warning signal and/or a switch-off signal when a critical winding temperature value is exceeded.