![]() In the following paragraphs two different methods of testing motors are presented: The direct method and the indirect one. The testing of standard motors is described in IEC 60034-2. The main difference between the standards is the way in which the fifth loss component stray loss (P stray), the additional load losses, is treated. ![]() ![]() Friction loss P fric – approximately 10-15%.Rotor winding loss – P cu2 – approximately 15%.Stator winding loss P cu1 – approximately 40-45%.The losses in an induction motor are distributed as follows: This seems in contradiction with the theoretical definition of the efficiency: The efficiency value obtained from the different testing standards can differ by several percent. For induction motors, the three most important ones are IEEE Standard 112, JEC 37 (Japan) and IEC 60034-2. ![]() Several standards for testing electric machinery exist on a worldwide basis. Standards for AC motors IEC 60034-2 Efficiency standards As this is a Grundfos publication, it is only natural that we should pay special attention to motors used for pumps – although much of the information contained within these pages will benefit all those with an interest in electrical motors. Complete hands-on approach to the repair and control of AC and DC motors. After all, motors are always designed to carry out specific tasks. ![]()
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