Q.1
The disc of an instrument using eddy current damping should be of
Q.2
For 275 kV transformers, using cold rolled grain oriented steel, which of the following values of flux density may be used?
Q.3
Hot rolled sheets have ______ value of permeability
Q.4
An ammeter is a
Q.5
________ cooling is the process of dissipating the armature and field winding losses to a cooling medium circulating within the winding insulation wall
Q.6
The switch board instruments
Q.7
An ohmmeter is a
Q.8
Hydrogen has a heat transfer co-efficient _____ times that of air
Q.9
The heat dissipating capability of transformers of ratings higher than 30 kVA in increased by providing which of the following?
Q.10
The distance between the starts of two consecutive coils measured in terms of coil sides is called
Q.11
In a 3-phase power measurement by two wattmeter method, both the watt meters had identical readings. The power factor of the load was
Q.12
The thermal conductivity of hydrogen is ______ times that of air
Q.13
The design of mechanical parts is particularly important in case of _____ speed machines.
Q.14
A voltage of about 200 V can be measured
Q.15
A current density of _________ is used for large power transformers with forced circulation of oil or with water cooling coils
Q.16
The resistance in the circuit of the moving coil of a dynamometer wattmeter should be
Q.17
E.m.f. of a Weston cell is accurately measured by
Q.18
Which of the following is measured by using a vector voltmeter ?
Q.19
_______ brushes are fragile and cause excessive wear of commutator,
Q.20
To avoid the effect of stray magnetic field in A.C. bridges we can use
Q.21
It is required to measure the true open circuit e.m.f. of a battery. The best device is
Q.22
In D.C. machines the width of the duct is usually
Q.23
The efficiency of a machine should be as ______ as possible to reduce the operating cost.
Q.24
Which of the following methods is used for air cooling of turbo-alternators ?
Q.25
In a Weston frequency meter, the magnetic axes of the two fixed coils are
Q.26
A practical formula for determining the thickness of insulation between low voltage and high voltage windings is
Q.27
In a 3-phase power measurement by two wattmeter method the reading of one of the wattmeter was zero. The power factor of the load must be
Q.28
Wattmeter cannot be designed on the principle of
Q.29
To measure a resistance with the help of a potentiometer it is
Q.30
A Weston synchronoscope is a
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