Lecture_10_AC_Machinery_Fundamentals

Lecture_10_AC_Machinery_Fundamentals - AC MACHINERY...

Info icon This preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon
04/11/17 1 Electrical Machines Aamir Hasan Khan AC MACHINERY FUNDAMENETALS
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
The Rotating Magnetic Field 04/11/17 2 Electrical Machines Aamir Hasan Khan If two magnetic fields are present in a machine, then a torque will be created which will tend to line up the two magnetic fields. If one magnetic field is produced by the stator of an ac machine and the other by the rotor, then a torque will be induced in the rotor which will cause the rotor to turn and align itself with the stator magnetic field. If there were some way to make the stator magnetic field rotate, then the induced torque in the rotor would cause it to ‘chase’ the stator magnetic field. a 3-phase set of currents, each of equal magnitude and differing in phase by 120º, flows in a 3-phase winding, then it will produce a rotating magnetic field of constant magnitude.
Image of page 2
04/11/17 3 Electrical Machines Aamir Hasan Khan (a) A simple three phase stator. Currents in this stator are assumed positive if they flow into the unprimed end and out the primed end of the coils. The H produced by each coil are also shown. (b) The magnetizing intensity vector H aa’ (t) produced by a current flowing in coil aa’. The Rotating Magnetic Field
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
04/11/17 4 Electrical Machines Aamir Hasan Khan Assume currents in the 3 coils are: A t I t i M aa sin ) ( ' A t I t i M bb ) 120 sin( ) ( ' A t I t i M cc ) 240 sin( ) ( ' The current in coil aa’ flows into the a end of the coil and out the a’ end of the coil. It produces the magnetic field intensity: m turns A t H t H M aa / 0 sin ) ( ' m turns A t H t H M bb / 120 ) 120 sin( ) ( ' m turns A t H t H M cc / 240 ) 240 sin( ) ( ' The Rotating Magnetic Field
Image of page 4
04/11/17 5 Electrical Machines Aamir Hasan Khan The flux densities equations are T t B t B M aa 0 sin ) ( ' T t B t B M bb 120 ) 120 sin( ) ( ' T t B t B M cc 240 ) 240 sin( ) ( ' Where B M = µ H M . The Rotating Magnetic Field
Image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
04/11/17 6 Electrical Machines Aamir Hasan Khan At time 0 t T B B M bb 120 ) 120 sin( ' T B B M cc 240 ) 240 sin( ' 0 ' aa B B net = B aa’ + B bb’ +B cc’ 240 2 3 120 2 3 0 M M B B 90 5 . 1 M B The Rotating Magnetic Field
Image of page 6
04/11/17 7 Electrical Machines Aamir Hasan Khan The Rotating Magnetic Field
Image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
04/11/17 8 Electrical Machines Aamir Hasan Khan 90 t At time T B B M bb 120 5 . 0 ' T B B M cc 240 5 . 0
Image of page 8
Image of page 9
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern