Which of the following is the commonly used type of electromagnets ?
Which of the following is the commonly used type of electromagnets ?
In D.C. machines, ir order to prevent excessive distortion of field form by the armature reaction, the field mmf must be made
In D.C. machines, ir order to prevent excessive distortion of field form by the armature reaction, the field mmf must be made
The voltage control in electric supply networks in required on account of which of the following reasons ?
The voltage control in electric supply networks in required on account of which of the following reasons ?
The density of hydrogen is _____ times the density of air.
The density of hydrogen is _____ times the density of air.
An induction meter can handle current up to
An induction meter can handle current up to
_______ is extensively used for those portions of magnetic circuit which carry steady flux and need superior mechanical properties ?
_______ is extensively used for those portions of magnetic circuit which carry steady flux and need superior mechanical properties ?
Which of the following is measured by using a vector voltmeter ?
Which of the following is measured by using a vector voltmeter ?
The usual values of maximum flux densities for distribution transformers using hot rolled silicon steel are
The usual values of maximum flux densities for distribution transformers using hot rolled silicon steel are
The resistance in the circuit of the moving coil of a dynamometer wattmeter should be
The resistance in the circuit of the moving coil of a dynamometer wattmeter should be
In transformers using hot rolled steel, the cross-section of the yoke is made about _____ greater than that of the core
In transformers using hot rolled steel, the cross-section of the yoke is made about _____ greater than that of the core
________ cooling is the process of dissipating the armature and field winding losses to a cooling medium circulating within the winding insulation wall
________ cooling is the process of dissipating the armature and field winding losses to a cooling medium circulating within the winding insulation wall
E.m.f. of a Weston cell is accurately measured by
E.m.f. of a Weston cell is accurately measured by
The time taken by the machine to attain 0.632 of its final steady temperature rise is called
The time taken by the machine to attain 0.632 of its final steady temperature rise is called
In Weston synchronoscope the moving coil is connected across
In Weston synchronoscope the moving coil is connected across
The thermal conductivity of hydrogen is ______ times that of air
The thermal conductivity of hydrogen is ______ times that of air
For 275 kV transformers, using cold rolled grain oriented steel, which of the following values of flux density may be used?
For 275 kV transformers, using cold rolled grain oriented steel, which of the following values of flux density may be used?
_______ brushes are fragile and cause excessive wear of commutator,
_______ brushes are fragile and cause excessive wear of commutator,
In a vibrating reed frequency meter the natural frequencies of two adjacent reeds have a difference of
In a vibrating reed frequency meter the natural frequencies of two adjacent reeds have a difference of
The heat dissipating capability of transformers of ratings higher than 30 kVA in increased by providing which of the following?
The heat dissipating capability of transformers of ratings higher than 30 kVA in increased by providing which of the following?
In a Schering bridge the potential of the detector above earth potential is
In a Schering bridge the potential of the detector above earth potential is
An instrument transformer is used to extend the range of
An instrument transformer is used to extend the range of
The noise produced by a ______ cooled machine is less as the rotor moves in a medium of smaller density.
The noise produced by a ______ cooled machine is less as the rotor moves in a medium of smaller density.
Wattmeter cannot be designed on the principle of
Wattmeter cannot be designed on the principle of
Basically a potentiometer is a device for
Basically a potentiometer is a device for
In a Weston synchronoscope, the fixed coils are connected across
In a Weston synchronoscope, the fixed coils are connected across
D.C. windings are
D.C. windings are
When the two coil sides forming a coil are spaced exactly one pole pitch apart they are said to be of
When the two coil sides forming a coil are spaced exactly one pole pitch apart they are said to be of
A Weston synchronoscope is a
A Weston synchronoscope is a
In ______ machines, the size of the shaft is decided by the critical speed which depends on the deflection of the shaft.
In ______ machines, the size of the shaft is decided by the critical speed which depends on the deflection of the shaft.
By which of the following methods motor rating for variable load drives can be determined ?
By which of the following methods motor rating for variable load drives can be determined ?
For measurements on high voltage capacitors, the suitable bridge is
For measurements on high voltage capacitors, the suitable bridge is
_________ electromagnets generally function as holding magnets.
_________ electromagnets generally function as holding magnets.
The design of mechanical parts is particularly important in case of _____ speed machines.
The design of mechanical parts is particularly important in case of _____ speed machines.
The function of shunt in an ammeter is to
The function of shunt in an ammeter is to
Commercial available medium size machines have a speed range of ______ .
Commercial available medium size machines have a speed range of ______ .
By which of the following methods the temperature rise of windings and other parts may be determined ?
By which of the following methods the temperature rise of windings and other parts may be determined ?
An ammeter is a
An ammeter is a
The value of exciting or magnetizing current depends upon which of the following factors ?
The value of exciting or magnetizing current depends upon which of the following factors ?
In order to achieve high accuracy, the slide wire of a potentiometer should be
In order to achieve high accuracy, the slide wire of a potentiometer should be
A phase shifting transformer is used in conjunction with
A phase shifting transformer is used in conjunction with
A practical formula for determining the thickness of insulation between low voltage and high voltage windings is
A practical formula for determining the thickness of insulation between low voltage and high voltage windings is
The rectifier instrument is not free from
The rectifier instrument is not free from
To measure a resistance with the help of a potentiometer it is
To measure a resistance with the help of a potentiometer it is
D.C. machines designed with a large value of air gap length have
D.C. machines designed with a large value of air gap length have
The distance between the starts of two consecutive coils measured in terms of coil sides is called
The distance between the starts of two consecutive coils measured in terms of coil sides is called
The heated parts of an electrical machine dissipate heat into their surroundings by which of the followingmodes of heat dissipation ?
The heated parts of an electrical machine dissipate heat into their surroundings by which of the followingmodes of heat dissipation ?
To avoid the effect of stray magnetic field in A.C. bridges we can use
To avoid the effect of stray magnetic field in A.C. bridges we can use
Which of the following methods may be adopted to reduce the effects of armature reaction?
Which of the following methods may be adopted to reduce the effects of armature reaction?
The length cf air gap to be provided in ______ is primarily determined by power factor consideration.
The length cf air gap to be provided in ______ is primarily determined by power factor consideration.
Induction type single phase energy meters measure electric energy in
Induction type single phase energy meters measure electric energy in
Power transformers should be designed to have maximum efficiency
Power transformers should be designed to have maximum efficiency
A current density of _________ is used for large power transformers with forced circulation of oil or with water cooling coils
A current density of _________ is used for large power transformers with forced circulation of oil or with water cooling coils
In a Weston frequency meter, the magnetic axes of the two fixed coils are
In a Weston frequency meter, the magnetic axes of the two fixed coils are
In a 3-phase power measurement by two wattmeter method, both the watt meters had identical readings. The power factor of the load was
In a 3-phase power measurement by two wattmeter method, both the watt meters had identical readings. The power factor of the load was
Multiple inlet system of air cooling of turbo-alternators can be used for machines of rating upto
Multiple inlet system of air cooling of turbo-alternators can be used for machines of rating upto
The electrical power to a meggar is provided by
The electrical power to a meggar is provided by
In direct cooled system using hydrogen both stator and rotor conductors are made
In direct cooled system using hydrogen both stator and rotor conductors are made
Which of the following properties a damping oil must possess ?
Which of the following properties a damping oil must possess ?
are used for construction of core of electromagnets.
are used for construction of core of electromagnets.
On which of the following variables heat convected depends ?
On which of the following variables heat convected depends ?
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
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
A potentiometer may be used for
A potentiometer may be used for
In induction motors, the length of air gap in kept as small as mechanically possible is order to have
In induction motors, the length of air gap in kept as small as mechanically possible is order to have
In D.C. machines the width of the duct is usually
In D.C. machines the width of the duct is usually
Two holes in the disc of energy meter are drilled at the opposite sides of the spindle to
Two holes in the disc of energy meter are drilled at the opposite sides of the spindle to
It is required to measure the true open circuit e.m.f. of a battery. The best device is
It is required to measure the true open circuit e.m.f. of a battery. The best device is
To measure radio frequency, the suitable frequency meter is
To measure radio frequency, the suitable frequency meter is
An ohmmeter is a
An ohmmeter is a
With conventional hydrogen cooling it is possible to increase the rating of a single unit to
With conventional hydrogen cooling it is possible to increase the rating of a single unit to
Which of the following materials is used in the manufacture of resistance grids to be used in the starters of largemotors ?
Which of the following materials is used in the manufacture of resistance grids to be used in the starters of largemotors ?
The design of electromagnets is based upon which of the following fundamental equations ?
The design of electromagnets is based upon which of the following fundamental equations ?
In a dynamometer 3-phase power factor meter, the planes of the two moving coils are at
In a dynamometer 3-phase power factor meter, the planes of the two moving coils are at
The action of electromagnetic machines can be related to which of the following basic principles ?
The action of electromagnetic machines can be related to which of the following basic principles ?
The efficiency of a machine should be as ______ as possible to reduce the operating cost.
The efficiency of a machine should be as ______ as possible to reduce the operating cost.
The switch board instruments
The switch board instruments
The weight of copper of both armature and field windings decreases with _____ in number of poles.
The weight of copper of both armature and field windings decreases with _____ in number of poles.
Hydrogen has a heat transfer co-efficient _____ times that of air
Hydrogen has a heat transfer co-efficient _____ times that of air
An induction wattmeter can be used for
An induction wattmeter can be used for
If the current in a capacitor leads the voltage by 80°, the loss angle of the capacitor is
If the current in a capacitor leads the voltage by 80°, the loss angle of the capacitor is
A moving-coil permanent-magnet instrument can be used as flux meter
A moving-coil permanent-magnet instrument can be used as flux meter
is usually used for brush rockers
is usually used for brush rockers
Various adjustments in an energy meter include
Various adjustments in an energy meter include
The household energy meter is
The household energy meter is
Most common form of A.C. meters met with in every day domestic and industrial installations are
Most common form of A.C. meters met with in every day domestic and industrial installations are
The disc of an instrument using eddy current damping should be of
The disc of an instrument using eddy current damping should be of
The flash point of transformer oil should be higher than
The flash point of transformer oil should be higher than
The cold rolled grain oriented steel has ______ permeability in the direction of the grain orientation.
The cold rolled grain oriented steel has ______ permeability in the direction of the grain orientation.
Instrument transformers are
Instrument transformers are
Which of the following instruments indicate the instantaneous value of the electrical quantity being measured at the time at which it is being measured ?
Which of the following instruments indicate the instantaneous value of the electrical quantity being measured at the time at which it is being measured ?
Which of the following methods does not take into account the maximum temperature rise under variable loadconditions ?
Which of the following methods does not take into account the maximum temperature rise under variable loadconditions ?
If an insulating material is operated beyond the maximum allowable temperature, its life is
If an insulating material is operated beyond the maximum allowable temperature, its life is
A dynamometer wattmeter can be used for
A dynamometer wattmeter can be used for
Which of the following methods is used for air cooling of turbo-alternators ?
Which of the following methods is used for air cooling of turbo-alternators ?
The winding where dummy coils are used is sometimes called
The winding where dummy coils are used is sometimes called
Standard resistor is made from
Standard resistor is made from
For large power transformers, self oil cooled type or air blast type which of the following values of current density may be used?
For large power transformers, self oil cooled type or air blast type which of the following values of current density may be used?
Hot rolled sheets have ______ value of permeability
Hot rolled sheets have ______ value of permeability
A voltage of about 200 V can be measured
A voltage of about 200 V can be measured
In D.C. machines the number of slots per pole usually lies
In D.C. machines the number of slots per pole usually lies
With direct water cooling it is possible to have ratings of about
With direct water cooling it is possible to have ratings of about
