Electrical Machines
A 2 pole synchronous machine is operating at 3000 rpm. Find the relation between electrical angular momentum (ωe) and mechanical angular momentum (ωm) ?

 ωe = 4*ωm
 ωe = 2*ωm
 ωe = ωm
 ωe = 1/2*ωm

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Electrical Machines
Flashing the field of DC generator means

  making the magnetic losses forces parallel.
  creating residual magnetism by a DC source.
  neutralising residual magnetism.
 increasing flux density by adding extra turns of winding.

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Electrical Machines
Two dc machines A and B, using the same conductor material, have armature circuit resistances of 0.4 Ω and 1.2 Ω respectively. Of the two machines,

 A is bigger than B for the same current rating
 B is bigger than A for the same current rating
 A is bigger than B for the same voltage rating
 both are of the same size for the same current rating

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Electrical Machines
Cogging in induction motor occurs when

 number of stator teeth - number of rotor teeth = 0.
 number of stator teeth - number of rotor teeth = even number.
 number of stator teeth - number of rotor teeth = negative number.
 number of stator teeth - number of rotor teeth = odd number.

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