Since the moving bar is not accelerating, the net force on the bar must be equal
ID: 2079346 • Letter: S
Question
Since the moving bar is not accelerating, the net force on the bar must be equal to zero. How can you justify this? A toroidal coil is wound on a plastic ring of rectangular cross section with inside diameter 30 cm, outside diameter 40 cm, and height 10 cm. The coil has 200 turns of round copper wire of 3-mm diameter. Calculate the magnetic flux density at the mean diameter of the coil when the coil current is 50 A. Assuming the answer of part a to be the uniform flux density within the coil, compute the flux linkages of the coil. Evaluate the percentage error involved in assuming uniform flux density in the coil. Find the resistance of the wire, given that the volume resistivity of copper is 17.2 X 10^-9 ohm-meter.Explanation / Answer
a. Magneto motive force= N*I=200*0.5=100AT
S(Reluctance)*A=2.198/12.56*10^(-7)=1.75*10^(6) Wb/AT
Magnetic Flux density(B)=N*I/S*A=100/1.75*10^(6)=57.14microWb
b.Flux linkage=B*A=403.71Wb
c.