Template for the Storyboard stage

General Instructions: The template shown is an example. You can add more slides if required. Include images for explaining the concepts. Label the images. Clearly list out the user interactions planned.

Prepare a questionnaire with answers on the concept for self-assessment of the user. If reviewer suggests modifications, you have to re-upload your storyboard with the modifications shown in bold letters. The blue band at the bottom will have suggestions about the slide contents.

Mention what will be your animation medium: 2D or 3D Mention the software to be used for animation development: JAVA, Flash, Blender, Shikav, Maya..etc Animation Medium: 2D

Title of the concept, subject. Name of the author 1 Magnetic Field in 3 phase Ac Machines Prof. Kishore Chatterjee

Definitions of the keywords used in the animation 2  Stator: The stationary part of the machine  Rotor: The rotating part of the machine.  Windings: Combination of coils wound on stator/rotor to produce magnetic field.  Magnetic field vector: Vector representing magnetic filed strength and direction.  Magnetic Flux= Ampere turns / Reluctance  Ampere turns = Number of turns * Current through each turn.  Reluctance = Opposition offered by the magnetic circuit to the flow of flux.

Describe the concept chosen and clearly illustrate how you want to explain the concept in the animation. 3 This animation will demonstrate the magnetic field produced by the stator of an ac machine. Rotor is not considered in this animation. Balanced 3-phase current is forced through the three phase stator windings (stator phase windings are displaced by 120 degree from each other). User can enter the frequency of ac currents in a box. Field due to individual phases and the resultant magnetic field can be seen in one figure. Other Figure will show the flux lines.

Problem Statement :Describe examples/experiments/analogies through which you will explain (use bullets). 4  Basic outlook of the 1 st figure in the animation is shown  Black Colored lines/text are solid and will be still during animation  Orange vectors:  Direction of the three vectors remain the same throughout the animation. (They are 120 degree separated from each other)‏  Their length (magnitude) are  Fa = 1*Cos (2*pi*F*t)‏  Fb = 1*Cos (2*pi*F*t – 2*pi/3)‏  Fc = 1*Cos (2*pi*F*t – 4*pi/3)‏  If their sign is –ve then show them in the opposite direction)‏  Green Vector:  Magnitude/ length = 1.5  Angle it makes with OA direction is given by = 2*pi*F*t radians  Hence this vector is rotating with fixed magnitude.  “t” is the time in seconds (in animation it can be scaled to 1:(10^n) actual time, so that user can clearly see the rotating/varying vectors)‏  “F” is the frequency of the currents. It will be given in Hz (cycles/second).

 A, B & C represents the three winding –A, -B & -C  O is the geometric centre of the machine  Fa, Fb, Fc are the magnetic filed vectors generated by A,B,C phase currents respectively.  Fa+Fb+Fc is the resultant magnetic filed vector

Problem statement: Stepwise description and illustrations (Add more slides if necessary)‏ 5  Outlook of the second figure in animation is shown  Black Colored lines/text are solid and will be still during animation  Orange lines patter will be the same always, the orange pattern will just rotate about point O with angle at any time = (2*pi*F*t) radians  Current position in the figure corresponds to angle = 0  Orange linear are the approximate flux lines  pi =

List out user interactions that will be there to enhance the understanding of the concept in the animation. 6  User should be allowed to enter the frequency, F in a box. (the acceptable range is 10Hz to 100Hz)‏  This F is used in the formulas stated in the slides 8 and 10.  All the black colored lines should appear first along with the box for “F” input.  Once the user enters “F”, and press a Enter/start button, then only other non-black lines should appear and should follow the rules given in previous slides.  There can also be a pause/continue button, which will pause/continue the animation.  During the animation if user enters the new F value and press Enter/Start button, then that new value of F should be used and animation should start from t=0.

A small questionnaire with answers based on the concept. 7 1) The nature of magnetic field distribution in space produced by the stator windings of an ideal induction motor is: A) Triangular B) Sinusoidal C) Rectangular D) Circular 2) 6pole stator is excited by balanced sinusoidal current of 628rad/sec. The speed ofrotation of the magnetic field is _________rpm. 3) The currents in A, B, C Phase winding are -5, 10, -5A respectively. The direction of the resultant magnetic field is along A) A-phase B) B-phase C) C-phase D) Between A and B Phase. 4) With the following connection of the windings and power supply, A-R’, B-Y’ & C-B’ (X-Y’ represents connection of X phase of motor to Y phase of the power supply) the magnetic field vector rotates in anti-clockwise direction. The direction of rotation of the magnetic field vector with connections A-Y’, B-B’ & C-R’ is ____________. 5) Three phase of an induction machine, which are displaced in space (and having sinusoidal distribution) by 120 degrees are fed with three sinusoidal currents which are displaced in time by 120 degrees. Then the resultant magnetic field will A) rotate with discrete steps. B) rotate continuously. C) remain stationary. D) have varying magnetic field strength with time. ANSWERS: 1) B, 2) 2000,3) B,4) anti-clockwise,5) A.

Links for further reading/references 8  Books:  P C Sen, “Principles of Electric Machines and Power Electronics”, Second Edition.  Nagrath Kothari, “Basic Electrical Engineering”, Second Edition

Credits 9