What is the orientation of the armature loop in a simple ac generator when the following is true. Explain your reasoning for each situation, and discuss why they do not occur at the same orientation.
(a) the value of the emf is a minimum
(b) the value of the magnetic flux is a minimum
29. May 2010 at 8:43 pm
a) The flux = N*B*A*cos(ωt) and the induced emf = -N*B*A*ω*sin(ωt)
The emf is a minimum (negative value) when the flux is zero. The flux is zero when the plane of the coil is parallel to the field. The emf is zero when the flux is a maximum because sin and cos are 90o out of phase
b) The magnetic flux is zero when the plane of the coil is parallel to field. The magnetic flux is at its most negative value when the coil is oriented at 180o to the field