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
Hydrogen has a heat transfer co-efficient _____ times that of air
Hydrogen has a heat transfer co-efficient _____ times that of air
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.
The household energy meter is
The household energy meter is
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 ?
To measure a resistance with the help of a potentiometer it is
To measure a resistance with the help of a potentiometer it 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
With direct water cooling it is possible to have ratings of about
With direct water cooling it is possible to have ratings of about
The winding where dummy coils are used is sometimes called
The winding where dummy coils are used is sometimes called
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.
is usually used for brush rockers
is usually used for brush rockers
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 ?
In D.C. machines the width of the duct is usually
In D.C. machines the width of the duct is usually
_______ brushes are fragile and cause excessive wear of commutator,
_______ brushes are fragile and cause excessive wear of commutator,
The density of hydrogen is _____ times the density of air.
The density of hydrogen is _____ times the density of air.
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.
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
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
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 ?
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 ?
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
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
Which of the following is measured by using a vector voltmeter ?
Which of the following is measured by using a vector voltmeter ?
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
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
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
An instrument transformer is used to extend the range of
An instrument transformer is used to extend the range of
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 ?
Instrument transformers are
Instrument transformers are
Induction type single phase energy meters measure electric energy in
Induction type single phase energy meters measure electric energy in
A dynamometer wattmeter can be used for
A dynamometer wattmeter can be used for
The thermal conductivity of hydrogen is ______ times that of air
The thermal conductivity of hydrogen is ______ times that of air
An induction meter can handle current up to
An induction meter can handle current up to
A voltage of about 200 V can be measured
A voltage of about 200 V can be measured
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
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 ?
An ammeter is a
An ammeter is a
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
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 rectifier instrument is not free from
The rectifier instrument is not free from
Basically a potentiometer is a device for
Basically a potentiometer is a device for
Which of the following properties a damping oil must possess ?
Which of the following properties a damping oil must possess ?
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
Which of the following is the commonly used type of electromagnets ?
Which of the following is the commonly used type of electromagnets ?
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 ?
________ 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
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
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.
Wattmeter cannot be designed on the principle of
Wattmeter cannot be designed on the principle of
A phase shifting transformer is used in conjunction with
A phase shifting transformer is used in conjunction with
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
To measure radio frequency, the suitable frequency meter is
To measure radio frequency, the suitable frequency meter is
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
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
The flash point of transformer oil should be higher than
The flash point of transformer oil should be higher than
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
are used for construction of core of electromagnets.
are used for construction of core of electromagnets.
The disc of an instrument using eddy current damping should be of
The disc of an instrument using eddy current damping should be of
In Weston synchronoscope the moving coil is connected across
In Weston synchronoscope the moving coil is connected across
D.C. windings are
D.C. windings are
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
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
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?
Various adjustments in an energy meter include
Various adjustments in an energy meter include
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.
_________ electromagnets generally function as holding magnets.
_________ electromagnets generally function as holding magnets.
An induction wattmeter can be used for
An induction wattmeter can 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
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.
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 ?
For measurements on high voltage capacitors, the suitable bridge is
For measurements on high voltage capacitors, the suitable bridge is
Power transformers should be designed to have maximum efficiency
Power transformers should be designed to have maximum efficiency
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
The electrical power to a meggar is provided by
The electrical power to a meggar is provided by
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 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 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 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
Commercial available medium size machines have a speed range of ______ .
Commercial available medium size machines have a speed range of ______ .
On which of the following variables heat convected depends ?
On which of the following variables heat convected depends ?
A moving-coil permanent-magnet instrument can be used as flux meter
A moving-coil permanent-magnet instrument can be used as flux meter
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?
_______ 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 ?
The switch board instruments
The switch board instruments
A Weston synchronoscope is a
A Weston synchronoscope is a
In D.C. machines the number of slots per pole usually lies
In D.C. machines the number of slots per pole usually lies
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
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 ______ 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.
In a Weston synchronoscope, the fixed coils are connected across
In a Weston synchronoscope, the fixed coils are connected across
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
Hot rolled sheets have ______ value of permeability
Hot rolled sheets have ______ value of permeability
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 ?
A potentiometer may be used for
A potentiometer may be used for
The function of shunt in an ammeter is to
The function of shunt in an ammeter is to
E.m.f. of a Weston cell is accurately measured by
E.m.f. of a Weston cell is accurately measured by
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
Standard resistor is made from
Standard resistor is made from
An ohmmeter is a
An ohmmeter is a
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
