电机学电机学电机学 (19).ppt

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1、Electrical MachineryComposition principle of AC winding and phase belt dividing uStrive to make wave forms of resultant EMF and resultant MMF be sine wave and big amplituded.uFor three-phase winding,EMF and MMF of each phase should be symmetrical,and resistance and impedance should be balanced;uCopp

2、er loss of winding should be small and copper usage amount should be small;uInsulation should be reliable,mechanical strength and heat dissipation condition should be good,manufacture should be convenient.4.2 Basic knowledges of AC winding I.Composition principle of AC windingArrangement law of 60 p

3、hase belt under a pair of magnetic poles:A-Z-B-X-C-Y.For the transformer whose magnetic pole pair number is P,the arrangement of phase belt is p times repetition from the situation when the number of magnetic pairs is p.A,X,B,Y,C,Z respectively are the two phase belts for each phase of one of the ma

4、gnetic pole pair,and the they are 180 electrical angle apart,for phase A,B and C,they are 120 electrical angle apart with each other.Phase belt:the serial electrical angle occupied by each winding under each magnetic pole.4.2 Composition of AC winding II.Phase belt dividing4.2 Composition of AC winding II.Phase belt dividingTHANKS FOR WATCHING!