A commutator motor with its armature supplied from variable voltage source. As the voltage is varied from 0 to 600V,the drive speed varies from 0 to 1600rpm, the field flux isconstant, all losses-ignored.
a) determine armature current if load torque is constant at420 N . m
b)a load is driven in the speed range of 1600 to 4000rpms. the armature V is constant at 600V. Determine torque available at maxspeed if the armature current of part (a) is not to b eexceeded.