Q.1
The weight of copper of both armature and field windings decreases with _____ in number of poles.
Q.2
Which of the following instruments indicate the instantaneous value of the electrical quantity being measured at the time at which it is being measured ?
Q.3
The density of hydrogen is _____ times the density of air.
Q.4
In a dynamometer 3-phase power factor meter, the planes of the two moving coils are at
Q.5
With conventional hydrogen cooling it is possible to increase the rating of a single unit to
Q.6
In Weston synchronoscope the moving coil is connected across
Q.7
The winding where dummy coils are used is sometimes called
Q.8
An instrument transformer is used to extend the range of
Q.9
The value of exciting or magnetizing current depends upon which of the following factors ?
Q.10
The voltage control in electric supply networks in required on account of which of the following reasons ?
Q.11
D.C. machines designed with a large value of air gap length have
Q.12
_________ electromagnets generally function as holding magnets.
Q.13
Which of the following is the commonly used type of electromagnets ?
Q.14
The noise produced by a ______ cooled machine is less as the rotor moves in a medium of smaller density.
Q.15
By which of the following methods the temperature rise of windings and other parts may be determined ?
Q.16
The function of shunt in an ammeter is to
Q.17
A phase shifting transformer is used in conjunction with
Q.18
By which of the following methods motor rating for variable load drives can be determined ?
Q.19
In direct cooled system using hydrogen both stator and rotor conductors are made
Q.20
On which of the following variables heat convected depends ?
Q.21
If the current in a capacitor leads the voltage by 80°, the loss angle of the capacitor is
Q.22
Is usually used for brush rockers
  • Mild steel
  • Copper
  • Aluminium
  • Cast-iron
Q.23
In D.C. machines the number of slots per pole usually lies
  • between 2 to 4
  • between 6 to 8
  • between 9 to 16
  • between 20 to 30
Q.24
In D.C. machines the usual limit of slot pitch is
  • between 5 to 10 mm
  • between 10 to 15 mm
  • between 15 to 20 mm
  • between 25 to 35 mm
Q.25
Which of the following methods may be adopted to reduce the effects of armaturereaction ?
  • Increase in length of air gap at pole tips
  • Increasing reluctance of pole tips
  • Compensating windings
  • All of the above
Q.26
The operation of a D.C. machine with large air gap lengths is comparatively
  • quiet
  • noisy
  • either of the above
  • none of the above
Q.27
In D.C. machines, the ____ in field mmf results in increase in size and cost of machines.
  • increase
  • decrease
  • either of the above
  • none of the above
Q.28
In D.C. machines, ir order to prevent excessive distortion of field form by the armaturereaction, the field mmf must be made
  • equal to that of armature mmf
  • less in comparison with the arma¬ture mmf
  • large in comparison with the arma-ture mmf
  • none of the above
Q.29
D.C. machines designed with a large value of air gap length have
  • worst, ventilation
  • poor ventilation
  • better ventilation
  • none of the above
Q.30
In D.C. machines the width of the duct is usually
  • 4 mm
  • 6 mm
  • 8 mm
  • 10 mm
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