Example Problem - Toroid: Difference between revisions

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== Read by  ==
== Read by  ==
== Points for page ==
Worth

Revision as of 16:39, 20 January 2010

By: Kirk Betz

Problem: Concerning Ampere's law Let look at a coil around a toroid shown in the figure below. The coil has N = 20 turns around the toroid. The toroid has an inside diameter of ID = 4 cm and an outside diameter OD = 5 cm. Determine the field intensity H along the mean path length within the toroid with a current i = 2.5 A.


Figure created by Kirk Betz


Solution:

Do symmetry the magnetic field intensity Hm along a circular contour within the toroid is constant. We can find the mean radius by


rm=(12)OD+ID2=2.25cm

Using the mean radius the mean path of length lm can be calculated.


lm=2πrm=0.141

With Ampere's Law (below) the field intensity along the mean path can be Found.

Hm=(Nilm)

Finally teh H_m can be calculated.

Hm=20x2.5.141=354.6A/m)

Since the width of the toroid is much smaller than the mean radius rm we can assume a uniform Hm throughout teh cross-section of the toroid.

Reviewed by

Will Griffith

Matthew Fetke

Read by

Points for page

Worth