Can you please explain what he is asking for The machine sho

Can you please explain what he is asking for?

The machine shown has two identical stator coils located 90 degrees apart. The currents are I_a=I_m cos 377t I_b=I_m cos (377t - Pi/2) Find the resultant mmf as a function of theta and t. Find the position of the peak mmf when t = 0, when t = 4.17 msec, and from this calculate the speed of the mmf wave. Consider the fundamental only.

Solution

The winding MMF depends only on the winding arrangement and the winding current.

The fundamental component of rectangular wave is found to be F₁=(4/)(Ni/2)cos, for 2-pole machine where =electrical space angle
The peak value of the sine MMF wave for a 2 pole machine is given by F_1p=(4/)(Ni/2)AT’s per pole= 2/(Ni) AT.

The armature MMF for a DC machine remains constant in amplitude and does not depend on the armature speed, also the MMF wave produced is seen to be a triangluar MMF wave

rotating magneticfield rotates with Ns

Ns=120*50/4=1500 speed rpm mmf=1500 rpm