The cold rolled grain oriented steel has ______ permeability in the direction of the grain orientation. (a) minimum (b) maximum (c) nil (d) none of the above

The cold rolled grain oriented steel has ______ permeability in the direction of the
grain orientation.
(a) minimum
(b) maximum
(c) nil
(d) none of the above
by

1 Answer

Answer :

(b) maximum
by

Related questions

For 275 kV transformers, using cold rolled grain oriented steel, which of the following values of flux density may be used? (a) 1.0 Wb/m2 (b) 1.1 Wb/m2 (c) 1.3 Wb/m2 (d) 1.6 Wb/m2 (e) None of the above

Description : For 275 kV transformers, using cold rolled grain oriented steel, which of the following values of flux density may be used? (a) 1.0 Wb/m2 (b) 1.1 Wb/m2 (c) 1.3 Wb/m2 (d) 1.6 Wb/m2 (e) None of the above

Last Answer : (d) 1.6 Wb/m2

Hot rolled sheets have ______ value of permeability (a) zero (b) low (c) high (d) none ofthe above

Description : Hot rolled sheets have ______ value of permeability (a) zero (b) low (c) high (d) none ofthe above

Last Answer : (b) low

The usual values of maximum flux densities for distribution transformers using hot rolled silicon steel are (a) 0.5 to 0.8 Wb/m2 (b) 0.8 to 1.0 Wb/m2 (c) 1.1 to 1.35 Wb/m2 (d) 1.4 to 1.8 Wb/m2

Description : The usual values of maximum flux densities for distribution transformers using hot rolled silicon steel are (a) 0.5 to 0.8 Wb/m2 (b) 0.8 to 1.0 Wb/m2 (c) 1.1 to 1.35 Wb/m2 (d) 1.4 to 1.8 Wb/m2

Last Answer : (c) 1.1 to 1.35 Wb/m2

In transformers using hot rolled steel, the cross-section of the yoke is made about _____ greater than that of the core (a) 5 percent (b) 10 percent (c) 15 percent (d) 30 percent (e) none of the above

Description : In transformers using hot rolled steel, the cross-section of the yoke is made about _____ greater than that of the core (a) 5 percent (b) 10 percent (c) 15 percent (d) 30 percent (e) none of the above

Last Answer : (c) 15 percent

________ has a lowrelative permeability and is used principally in field frames when cost is of primary importance and extra weight is not objectionable. (a) Cast steel (b) Aluminium (c) Soft steel (d) Cast iron

Description : ________ has a lowrelative permeability and is used principally in field frames when cost is of primary importance and extra weight is not objectionable. (a) Cast steel (b) Aluminium (c) Soft steel (d) Cast iron

Last Answer : (d) Cast iron

What is the permissible flux density in case of cold rolled grained oriented steel?

Description : What is the permissible flux density in case of cold rolled grained oriented steel?

Last Answer : The permissible flux density in case of cold rolled grained oriented steel is 1.7 Wb/m2.

In self cooled motors the cooling time constant is about ______ than the heating time constant because cooling conditions are worse at standstill. (a) 2 to 3 times greater (b) 3 to 4 times greater (c) 4 to 5 times greater (d) none of the above

Description : In self cooled motors the cooling time constant is about ______ than the heating time constant because cooling conditions are worse at standstill. (a) 2 to 3 times greater (b) 3 to 4 times greater (c) 4 to 5 times greater (d) none of the above

Last Answer : (a) 2 to 3 times greater

The noise produced by a ______ cooled machine is less as the rotor moves in a medium of smaller density. (a) air (b) hydrogen (c) either (a) or (b) (d) none of the above

Description : The noise produced by a ______ cooled machine is less as the rotor moves in a medium of smaller density. (a) air (b) hydrogen (c) either (a) or (b) (d) none of the above

Last Answer : (b) hydrogen

The thermal conductivity of hydrogen is ______ times that of air (a) 2 (b) 3 (c) 5 (d) 7

Description : The thermal conductivity of hydrogen is ______ times that of air (a) 2 (b) 3 (c) 5 (d) 7

Last Answer : (d) 7

Materials exhibiting zero value of resistivity are known as ______ . (a) conductors (b) semiconductors (c) insulators (d) superconductors

Description : Materials exhibiting zero value of resistivity are known as ______ . (a) conductors (b) semiconductors (c) insulators (d) superconductors

Last Answer : (d) superconductors

Aluminium when adopted as a conductor material in ______ transformers, decreases the overall cost of the transformer (a) small size (b) medium size (c) large size (d) any of the above size

Description : Aluminium when adopted as a conductor material in ______ transformers, decreases the overall cost of the transformer (a) small size (b) medium size (c) large size (d) any of the above size

Last Answer : (a) small size

Commercial available medium size machines have a speed range of ______ . (a) 200 to 400 r.p.m. (b) 600 to 1000 r.p.m. (c) 1000 to 1500 r.p.m. (d) 2000 to 2500 r.p.m.

Description : Commercial available medium size machines have a speed range of ______ . (a) 200 to 400 r.p.m. (b) 600 to 1000 r.p.m. (c) 1000 to 1500 r.p.m. (d) 2000 to 2500 r.p.m.

Last Answer : (d) 2000 to 2500 r.p.m.

The length cf air gap to be provided in ______ is primarily determined by power factor consideration. (a) d.c. series motor . (b) d.c. shunt motor (c) induction motor (d) synchronous motor

Description : The length cf air gap to be provided in ______ is primarily determined by power factor consideration. (a) d.c. series motor . (b) d.c. shunt motor (c) induction motor (d) synchronous motor

Last Answer : (c) induction motor

In ______ machines, the size of the shaft is decided by the critical speed which depends on the deflection of the shaft. (a) small (b) medium (c) large (d) any of the above.

Description : In ______ machines, the size of the shaft is decided by the critical speed which depends on the deflection of the shaft. (a) small (b) medium (c) large (d) any of the above.

Last Answer : (c) large

The efficiency of a machine should be as ______ as possible to reduce the operating cost. (a) high (b) low (c) either of the above (d) none of the above

Description : The efficiency of a machine should be as ______ as possible to reduce the operating cost. (a) high (b) low (c) either of the above (d) none of the above

Last Answer : (a) high

is usually used for brush rockers (a) Mild steel (b) Copper (c) Aluminium (d) Cast-iron

Description : is usually used for brush rockers (a) Mild steel (b) Copper (c) Aluminium (d) Cast-iron

Last Answer : (d) Cast-iron

______is extensively used for those portions of magnetic circuit which carry steady flux and need superior mechanical properties ? (a) Grey cast-iron (b) Cast steel (c) High carbon steel (d) Stainless steel

Description : ______is extensively used for those portions of magnetic circuit which carry steady flux and need superior mechanical properties ? (a) Grey cast-iron (b) Cast steel (c) High carbon steel (d) Stainless steel

Last Answer : (b) Cast steel

Which ofthe following materials is used in the manufacture of resistance grids to be used in the starters of large motors ? (a) Copper (b) Aluminium (c) Steel (d) Cast-iron

Description : Which ofthe following materials is used in the manufacture of resistance grids to be used in the starters of large motors ? (a) Copper (b) Aluminium (c) Steel (d) Cast-iron

Last Answer : (d) Cast-iron

is universally used for windings of electrical machines because it is easily workable without any possibility of fracture. (a) Silver (b) Steel (c) Aluminium (d) Copper

Description : is universally used for windings of electrical machines because it is easily workable without any possibility of fracture. (a) Silver (b) Steel (c) Aluminium (d) Copper

Last Answer : (d) Copper

The minimum water content at which the soil just begins to crumble when rolled into threads 3 mm in diameter, is known (A) Liquid limit (B) Plastic limit (C) Shrinkage limit (D) Permeability limit

Description : The minimum water content at which the soil just begins to crumble when rolled into threads 3 mm in diameter, is known (A) Liquid limit (B) Plastic limit (C) Shrinkage limit (D) Permeability limit

Last Answer : (B) Plastic limit

Power transformers should be designed to have maximum efficiency (a) at one-fourth load (b) at one-half load (c) at or near full load (d) any of the above

Description : Power transformers should be designed to have maximum efficiency (a) at one-fourth load (b) at one-half load (c) at or near full load (d) any of the above

Last Answer : (c) at or near full load

Which of the following methods does not take into account the maximum temperature rise under variable load conditions ? (a) Equivalent power method (b) Equivalent current method (c) Method of average losses (d) Equivalent torque method

Description : Which of the following methods does not take into account the maximum temperature rise under variable load conditions ? (a) Equivalent power method (b) Equivalent current method (c) Method of average losses (d) Equivalent torque method

Last Answer : (c) Method of average losses

If an insulating material is operated beyond the maximum allowable temperature, its life is (a) drastically increased (b) drastically reduced (c) unaffected (d) none of the above

Description : If an insulating material is operated beyond the maximum allowable temperature, its life is (a) drastically increased (b) drastically reduced (c) unaffected (d) none of the above

Last Answer : (b) drastically reduced

In D.C. machines the number of slots per pole usually lies (a) between 2 to 4 (b) between 6 to 8 (c) between 9 to 16 (d) between 20 to 30

Description : In D.C. machines the number of slots per pole usually lies (a) between 2 to 4 (b) between 6 to 8 (c) between 9 to 16 (d) between 20 to 30

Last Answer : (c) between 9 to 16

In D.C. machines the usual limit of slot pitch is (a) between 5 to 10 mm (b) between 10 to 15 mm (c) between 15 to 20 mm (d) between 25 to 35 mm

Description : In D.C. machines the usual limit of slot pitch is (a) between 5 to 10 mm (b) between 10 to 15 mm (c) between 15 to 20 mm (d) between 25 to 35 mm

Last Answer : (d) between 25 to 35 mm

Which of the following methods may be adopted to reduce the effects of armature reaction ? (a) Increase in length of air gap at pole tips (b) Increasing reluctance of pole tips (c) Compensating windings (d) Interpoles (e) All of the above

Description : Which of the following methods may be adopted to reduce the effects of armature reaction ? (a) Increase in length of air gap at pole tips (b) Increasing reluctance of pole tips (c) Compensating windings (d) Interpoles (e) All of the above

Last Answer : (e) All of the above

The operation of a D.C. machine with large air gap lengths is comparatively (a) quiet (b) noisy (c) either of the above (d) none of the above

Description : The operation of a D.C. machine with large air gap lengths is comparatively (a) quiet (b) noisy (c) either of the above (d) none of the above

Last Answer : (a) quiet

In D.C. machines, the ____ in field mmf results in increase in size and cost of machines. (a) increase (b) decrease (c) either of the above (d) none of the above

Description : In D.C. machines, the ____ in field mmf results in increase in size and cost of machines. (a) increase (b) decrease (c) either of the above (d) none of the above

Last Answer : (a) increase

In D.C. machines, ir order to prevent excessive distortion of field form by the armature reaction, the field mmf must be made (a) equal to that of armature mmf (b) less in comparison with the arma¬ture mmf (c) large in comparison with the arma-ture mmf (d) none of the above

Description : In D.C. machines, ir order to prevent excessive distortion of field form by the armature reaction, the field mmf must be made (a) equal to that of armature mmf (b) less in comparison with the arma¬ture mmf (c) large in comparison with the arma-ture mmf (d) none of the above

Last Answer : (c) large in comparison with the arma-ture mmf

D.C. machines designed with a large value of air gap length have (a) worst, ventilation (b) poor ventilation (c) better ventilation (d) none of the above

Description : D.C. machines designed with a large value of air gap length have (a) worst, ventilation (b) poor ventilation (c) better ventilation (d) none of the above

Last Answer : (c) better ventilation

In D.C. machines the width of the duct is usually (a) 4 mm (b) 6 mm (c) 8 mm (d) 10 mm

Description : In D.C. machines the width of the duct is usually (a) 4 mm (b) 6 mm (c) 8 mm (d) 10 mm

Last Answer : (d) 10 mm

In a D.C. machine, the value of peripheral speed should not, normally, exceed (a) 10 m/s (b) 20 m/s (c) 30 m/s (d) 40 m/s

Description : In a D.C. machine, the value of peripheral speed should not, normally, exceed (a) 10 m/s (b) 20 m/s (c) 30 m/s (d) 40 m/s

Last Answer : (c) 30 m/s

In a D.C. machine the current per brush arm should not be more than (a) 100 A (6) 200 A (e) 300 A (d) 400 A

Description : In a D.C. machine the current per brush arm should not be more than (a) 100 A (6) 200 A (e) 300 A (d) 400 A

Last Answer : (d) 400 A

In a D.C. machine the number of brush arms is _____ the number of poles. (a) less than (b) equal to (c) greater than (d) none of the above

Description : In a D.C. machine the number of brush arms is _____ the number of poles. (a) less than (b) equal to (c) greater than (d) none of the above

Last Answer : (b) equal to

The weight of copper of both armature and field windings decreases with _____ in number of poles. (a) increase (b) decrease (c) either of the above (d) none of the above

Description : The weight of copper of both armature and field windings decreases with _____ in number of poles. (a) increase (b) decrease (c) either of the above (d) none of the above

Last Answer : (a) increase

Which of the following problem arises in D.C. motors which are fed from thyristor bridge circuits ? (a) Increased I R losses (b) Increased core losses (c) Poor commutation (d) Change in motor parameters (e) All of the above

Description : Which of the following problem arises in D.C. motors which are fed from thyristor bridge circuits ? (a) Increased I R losses (b) Increased core losses (c) Poor commutation (d) Change in motor parameters (e) All of the above

Last Answer : (e) All of the above

________ is the common method of applying brushes to the commntator. (a) Radial (b) Trailing (c) Reaction (d) All of the above

Description : ________ is the common method of applying brushes to the commntator. (a) Radial (b) Trailing (c) Reaction (d) All of the above

Last Answer : (d) All of the above

Which of the following brushes can be used for high values of current density ? (a) Metal graphite brushes (b) Hard carbon brushes (c) Electro-graphitic brushes (d) Natural graphite brushes

Description : Which of the following brushes can be used for high values of current density ? (a) Metal graphite brushes (b) Hard carbon brushes (c) Electro-graphitic brushes (d) Natural graphite brushes

Last Answer : (a) Metal graphite brushes

_____ brushes are fragile and cause excessive wear of commutator, (a) Natural graphite (b) Hard carbon (c) Electro graphitic (d) Metal graphite

Description : _____ brushes are fragile and cause excessive wear of commutator, (a) Natural graphite (b) Hard carbon (c) Electro graphitic (d) Metal graphite

Last Answer : (a) Natural graphite

The laminations of the armature of a D.C. machine are usually _____ thick. (a) 0.1 to 0.2 mm (b) 0.2 to 0.3 mm (c) 0.3 to 0.4 mm (d) 0.4 to 0.5 mm

Description : The laminations of the armature of a D.C. machine are usually _____ thick. (a) 0.1 to 0.2 mm (b) 0.2 to 0.3 mm (c) 0.3 to 0.4 mm (d) 0.4 to 0.5 mm

Last Answer : (d) 0.4 to 0.5 mm

The stator of a D.C. machine comprises of (a) main poles (6) interpoles (c) frame (d) all of the above

Description : The stator of a D.C. machine comprises of (a) main poles (6) interpoles (c) frame (d) all of the above

Last Answer : (d) all of the above

D.C. servomotors are used in (a) purely D.C. control systems (6) purely AC. control systems (c) both D.C. and AC. control systems (d) none of the above

Description : D.C. servomotors are used in (a) purely D.C. control systems (6) purely AC. control systems (c) both D.C. and AC. control systems (d) none of the above

Last Answer : (a) purely D.C. control systems

Which of the following in an application of D.C. motors? (a) Traction (b) Drives for process industry (c) Battery driven vehicles (d) Automatic control (e) All of the above

Description : Which of the following in an application of D.C. motors? (a) Traction (b) Drives for process industry (c) Battery driven vehicles (d) Automatic control (e) All of the above

Last Answer : (e) All of the above

The surge phenomenon is particularly important in case of (a) low voltage transformers (b) medium voltage transformers (c) high voltage transformers (d) any of the above

Description : The surge phenomenon is particularly important in case of (a) low voltage transformers (b) medium voltage transformers (c) high voltage transformers (d) any of the above

Last Answer : (c) high voltage transformers

The cylindrical windings using circular conductors are used for current rating of (a) upto 20 A (b) upto 40 A (c) upto 60 A (d) upto 80 A

Description : The cylindrical windings using circular conductors are used for current rating of (a) upto 20 A (b) upto 40 A (c) upto 60 A (d) upto 80 A

Last Answer : (d) upto 80 A

The insulation between windings and grounded core and the insulation between the windings of the same phase is called (a) minor insulation (b) major insulation (c) either of the above (d) none of the above

Description : The insulation between windings and grounded core and the insulation between the windings of the same phase is called (a) minor insulation (b) major insulation (c) either of the above (d) none of the above

Last Answer : (b) major insulation

A practical formula for determining the thickness of insulation between low voltage and high voltage windings is (a) 1 + 0.2 kVmm (6) 2 + 0.5 kVmm (c) 4 + 0.7 kV mm (d) 5 + 0.9 kV mm

Description : A practical formula for determining the thickness of insulation between low voltage and high voltage windings is (a) 1 + 0.2 kVmm (6) 2 + 0.5 kVmm (c) 4 + 0.7 kV mm (d) 5 + 0.9 kV mm

Last Answer : (d) 5 + 0.9 kV mm

Which of the following is the basic consideration in the design of insulation ? (a) Electrical considerations (b) Mechanical considerations (c) Thermal considerations (d) All of the above

Description : Which of the following is the basic consideration in the design of insulation ? (a) Electrical considerations (b) Mechanical considerations (c) Thermal considerations (d) All of the above

Last Answer : (d) All of the above

The high voltage winding is usually which of the following type ? (a) Cylindrical winding with circular conductors (b) Cross-over winding with either circular or small rectangular conductors (c) Continuous disc type winding with rectangular conductors (d) All of the above types

Description : The high voltage winding is usually which of the following type ? (a) Cylindrical winding with circular conductors (b) Cross-over winding with either circular or small rectangular conductors (c) Continuous disc type winding with rectangular conductors (d) All of the above types

Last Answer : (d) All of the above types

A current density of _____ is ilsed for large power transformers with forced circulation of oil or with water cooling coils (a) 1.5 to 2.5 A/mm2 (b) 3.5 to 4.5 A/mm2 (c) 4.0 to 5.0 A/mm2 (d) 5.4 to 6.2 A/mm2

Description : A current density of _____ is ilsed for large power transformers with forced circulation of oil or with water cooling coils (a) 1.5 to 2.5 A/mm2 (b) 3.5 to 4.5 A/mm2 (c) 4.0 to 5.0 A/mm2 (d) 5.4 to 6.2 A/mm2

Last Answer : (d) 5.4 to 6.2 A/mm2