Q.1
_______ is extensively used for those portions of magnetic circuit which carry steady flux and need superior mechanical properties ?
Q.2
In a vibrating reed frequency meter the natural frequencies of two adjacent reeds have a difference of
Q.3
Dummy coil should not be used in
Q.4
The heated parts of an electrical machine dissipate heat into their surroundings by which of the followingmodes of heat dissipation ?
Q.5
The action of electromagnetic machines can be related to which of the following basic principles ?
Q.6
Multiple inlet system of air cooling of turbo-alternators can be used for machines of rating upto
Q.7
The household energy meter is
Q.8
The flash point of transformer oil should be higher than
Q.9
Which of the following essential features is possessed by an indicating instrument ?
Q.10
Multilayer helical windings are commonly used in the transformers as high voltage windings
Q.11
Which of the following properties a damping oil must possess ?
Q.12
In transformers using hot rolled steel, the cross-section of the yoke is made about _____ greater than that of the core
Q.13
Which of the following devices may be used for extending the range of instruments ?
Q.14
The operating voltage of a meggar is about
Q.15
Impose limitation on design.
Q.16
The surge phenomenon is particularly important in case of
Q.17
An induction meter can handle current up to
Q.18
Which of the following brushes can be used for high values of current density ?
Q.19
Which of the following is an advantage of hydrogen cooling?
Q.20
The insulation between windings and grounded core and the insulation between the windings of the same phase is
Q.21
Commercial available medium size machines have a speed range of ______ .
Q.22
The usual values of maximum flux densities for distribution transformers using hot rolled silicon steel are
Q.23
An induction wattmeter can be used for
Q.24
For large power transformers, self oil cooled type or air blast type which of the following values of current density may be used?
Q.25
If an insulating material is operated beyond the maximum allowable temperature, its life is
Q.26
The electrical power to a meggar is provided by
Q.27
In D.C. machines, ir order to prevent excessive distortion of field form by the armature reaction, the field mmf must be made
Q.28
Basically a potentiometer is a device for
Q.29
A potentiometer may be used for
Q.30
The rectifier instrument is not free from
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