Electrical Machines
A dc shunt generator, when commissioned after a major repair of the field system, failed to build Up voltage. It was because

 field resistance was higher than critical resistance
 field system lost residual magnetism
 field winding was wrongly connected
 there was a break in the armature circuit

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

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

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Electrical Machines
Consider the following statements regarding the magnetization characteristics of a dc generator : 1. It represents the variation of field flux with field current. 2. Variation of open-circuit terminal voltage with field current is independent of speed 3. It is non-linear from zero to rated field current 4. It helps to determine the critical field resistance at a given speed 5. It always starts from the origin Which of these statements are correct ?

 3 and 5
 1, 2 and 5
 1 and 4
 2, 3 and 4

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