Permissible number of switches on per hour of electric motors for horizontally moving crane mechanisms

  • 1 Technical University – Gabrovo, Republic of Bulgaria


Paper deals with determining the permissible number of switches on per hour depending on the load and operating mode parameters – starting and stopping times, pause duration, etc. The criterion is that the overheating of the stator winding does not exceed the overheating at nominal mode and load. The basis of the chosen method is the assumption that the electric motor is assumed to be a conditionally uniform body, i.e. a body made of the same material with an infinitely large thermal conductivity and therefore having the same temperature throughout its volume under all possible modes and loads. The results of the calculations with a computer program
implemented are presented in tabular form.



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