Electrical Machines
What is/are the necessary conditions for voltage build up in self excited generator?

 Field winding should be properly connected to armature winding.
 Field winding resistance should be less than critical resistance.
 Poles should contain residual flux.
All of these

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Electrical Machines
A dc shunt generator, when driven without any excitation, showed an open circuit voltage of 12 V. When the field winding was excited, the voltage dropped to zero. It happened because

 field resistance was higher than critical resistance
 there was a break in the armature circuit
 there was no residual magnetism in the field circuit
 field winding was wrongly connected

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Electrical Machines
Which is the arrangement of windings in a core type single phase transformer?

 Lv on one core limb and hv on the other
 Sandwiched lv and hv discs on each core limb
 Half hv inside and half lv outside on each core limb
 Half lv inside and half hv outside on each core limb

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