Generation of voltage for each phase are same of a turbogenerator.Although the short circuit current flow when two phase of turbogenerator are shorted(where current can't flow without potential difference),why?

Why a dc generator gives result during two different condition,- 1)separately exited gen.- Eg=110 V, field current=0.25 A. 2) self exited gen.- Eg=30 V, field current=0.025 A.

During speed control of dc shunt motor with flux control methode,when armature voltage is constant, How can it possible to increasing the armature current?

Why we use two wattmeter during block rotor test and no load test of 3phase induction motor? And how can we understand the neat power requirement of from this test?