Electric_Machinery_Fundamentals_4th_Edition_部分11.pdf

ACMAC HINERYFUNDA MENTALS 257 B, , , , , , , , \ II.., _ f-ja _-- l__ _ _____ , , , , , , I I1~ HR r= 180 - a FI GURE 4- 18 The components magnetic flux density inside Ihe machine of Figure 4--17. HR = Ci (4- 53) where C is a constant of proportiona lity . 2. 1lle ang le between the peak of the stator flux density Bs and the peak of the rotor magnetizing inte nsity HR is y. Furthennore, y=180o -a (4- 54) sin y= sin ( 180° _a) = sin 0: (4- 55) By combining the se two observati ons, the torque on the loop can be expressed as Tioo = KHI13 s sin a count erc lockwi se (4- 56) where K is a constant dependent on the constru cti on of the machine. Note that both the magnitude and the direction of the torque can be expressed by the equati on ITind - KHR X Bs I (4- 57) Finall y, sin ce B R = /LHR, thi s eq uation can be ree xpressed