Magnetic device with moving iron element , Mechanical Engineering

A singly excited magnetic device with a moving iron element is illustrated in the figure below.

241_notation.png

g = 0.10 mm

d = 2.0 cm

b = 3.0 cm

Assume the mmf in the iron and the effects of fringing and leakage flux are negligible.

a) Use the force density expression B2/2ì0 to find the force pulling the moving part to the right if B in the center leg is 1.5 T and x = 0.10 mm. Also find the coil current for this condition.

b) Find the force at x =1 mm if the current is held constant at the value in part a.

2) Two iron sheets of width D and thickness d overlap by an amount x as shown in the figure. The flux in the upper and lower sheets is and the air gap between the two sheets is y.

Find the flux  and the magnetic force(from the derivative of reluctance) in the x and y directions if:

D = 20 cm d = 1 mm y = 1 mm x = 2 cm B = 1.5 T (in iron away from gap)

Neglect fringing, leakage and the mmf in the iron.

1700_two iron sheets.png

3) Introduction to Rotating Machines

The uniform air gap rotating machine model shown in the figure at the right has a 4-pole concentrated coil winding on the stator with N total turns. When excited with a current of 5.0 A rms at 60 hz the machine has a peak air gap flux density of Bpeak =1.0 T. Assume in all cases that the iron can be considered to have infinite permeability and end effects can be neglected abd that

L = 20 cm r = 10 cm N = 50

2212_2 turns.png

2365_conductor.png

a) What would be the peak air gap mmf of this machine? What is the peak value of the spatial

fundamental component of the air gap B -field?

b) What is the peak flux per pole of the machine? What should the width of the yoke 'd' so that the peak flux density in the yoke is the same as in the air gap?

c) What would be the peak torque produced if a uniform distribution of conductors with 100 total conductors (25 for each pole) and carrying the same 5.0 A rms in series with the original winding were added as shown in the figure below? What would be the average torque?

d) If the conductors of this machine are relocated to create a two pole concentrated coil machine, what value of rms current would be needed to give a peak field of 1.0 T? What would be the new 'd' to keep the yoke flux density =1.0 T?

838_Bpeak.png

e) Assume two more windings identical with the original 4-pole concentrated coil winding but displaced by 120 electrical degrees (60° mechanical) are added to form a three phase winding. Assuming balanced three phase sinusoidal currents of 5.0 A rms and given that the Fourier series of a rectangular wave is find

1866_reaction.png

the peak amplitude and mechanical rotation speed of the fundamental rotating B-field.

Posted Date: 3/16/2013 3:34:01 AM | Location : United States







Related Discussions:- Magnetic device with moving iron element , Assignment Help, Ask Question on Magnetic device with moving iron element , Get Answer, Expert's Help, Magnetic device with moving iron element Discussions

Write discussion on Magnetic device with moving iron element
Your posts are moderated
Related Questions
why 4R kinematic chain do not form different mechanisms?

Type of Lubrication Systems The complete lubrication of a vehicle can be divided into two systems. (a) Engine lubrication system. (b) Chassis lubrication system.

(a) Describe a vector and scalar ? (b) What is meant by line of action of vector ? (c) What are displacement vectors and position vector ? (d) Calculate the component of t

sensitivity of governors


Working Principle of Carburettor : All carburettors work on one basic principle, the venturi. A venturi is a very simple device that changes air pressure by changing the velocity

Manual Engineering Drawing: The physical object is to be drawn (Do not take photographs of the object or use it as a template that you trace with) in class as an isometric dra

Hot Pressing This pressing requires application of pressure throughout sintering. In usual understanding hot pressing comprises in applying a unidirectional pressure via the a

(a) Calculate the natural frequency of mass m = 1 Kg placed at one end of a cantilever beam of negligible mass. Length of cantilever = 500 mm, d = 30 mm, b = 20 mm, E = 210x10 9 N

Loa d Diagram and BM D fro m the Given SF D: Q: Shear force diagram of simply supported beam is given in the figure below.  Calculate the support reactions of beam and