________ 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

________ 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
by

1 Answer

Answer :

(d) Cast iron
by

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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

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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

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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

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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

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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

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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

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cooling is the process of dissipating the armature and field winding losses to a cooling medium circulating within the winding insulation wall (a) Direct (b) Indirect (c) Conventional (d) Any ofthe above

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The change in flux linkages can be caused in which ofthe following ways ? (a) The flux is constant with respect to time and is stationary and the coil moves through it (b) The coil is stationary with respect to flux and the flux varies in magnitude with respect to time (c) Both the changes mentioned above occure together, i.e., the coil moves through a time varying field (d) All ofthe above

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The slot leakage can be calculated by making which of the following assumptions ? (a) The current in the slot conductors is uniformly distributed over their cross-section (b) The leakage path is straight across the slot and around the iron at the bottom (c) The permanence of air paths is only considered. The reluctance of iron paths is assumed as zero (d) All of the above

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When placed in a magnetic field, which of the materials listed will maintain the highest permeability? A. Glass B. Bakelite C. Soft iron D. Aluminum

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Pebble mills are tumbling mills widely used for grinding in the manufacture of paints & pigments and cosmetic industries, where iron contamination in the product is highly objectionable. Pebbles used in pebble mill are made of (A) Bronze (B) Stainless steel (C) Flint or porcelain (D) Concrete

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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

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A mould board of MB plough is made of? a Cast iron b Chilled cast iron c Mild steel d Soft centre steel

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Last Answer : (A) Aluminium, mild steel, stainless steel, concrete & tin

100% H2SO4 at 30°C can't be stored in a vessel made/lined with (A) Cast iron and high silicon iron (B) Mild steel and stainless steel (C) Aluminium, tin and rubber (D) Teflon, glass and porcelain

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Spray dryer for evaporating milk to produce milk powder is made of (A) Lead lined steel (B) Stainless steel (C) Aluminium (D) Cast iron

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Acetaldehyde is shipped in __________ drums. (A) Cast iron (B) Steel (C) Aluminium (D) Either (B) & (C)

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For handling sulphuric acid of 95% strength, the suitable material of construction for pipes is (A) Stainless steel (B) Cast iron (C) Aluminium (D) Nickel

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Hydrocyanic acid is not shipped in (A) Cast iron vessels (B) Steel cylinders (C) Aluminium containers (D) Monel drums

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Mixing vessel used for the chlorination of methane to produce methyl chloride is made of (A) Copper (B) Cast iron (C) Aluminium (D) High carbon steel

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Polymerisation reactor used in the production of styrene butadiene rubber (SBR) is made of (A) Stainless steel or glass lined steel (B) Nickel clad steel (C) High silicon cast iron (D) Aluminium

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Last Answer : (A) Stainless steel or glass lined steel

Which of the following material of construction may be recommended by a chemical engineer for handling a gaseous chlorine (dry or wet) stream in a fluid flow system? (A) High silicon iron, silicon rubber, Kel-F and Teflon (B) Mild steel and stainless steel (C) Cast iron, tin and aluminium (D) Copper, nickel and Monel

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Last Answer : (A) High silicon iron, silicon rubber, Kel-F and Teflon

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Last Answer : (A) Aluminium

Compressed dry air is used as the cutting fluid, while machining (A) Steel (B) Cast iron (C) Aluminium (D) None of these

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Electromagnet is constructed with which of the following? (1) Steel (2) Soft Iron (3) Aluminium (4) Nickel

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Electromagnet is constructed with which of the following ? (1) Steel (2) Soft Iron (3) Aluminium (4) Nickel

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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

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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

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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

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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

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Last Answer : (a) quiet

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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

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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

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