Give the purpose and location of neutral section and section insulator. 

1 Answer

Answer :

Purpose of Neutral section: Passing of pantograph under insulated overlap will cause short circuit between two phases, damaging OHE & pantograph. To avoid this bridging, a neutral section is inserted between them. Location: Located between two substations. Purpose of Section insulator: Section insulators are provided to insulate OHE of one elementary section from the OHE of another adjacent elementary section. Location: Located at cross over from one track to other, from main line to siding.

Related questions

Description : Give purpose and location of i) Uninsulated overlap. ii) Insulated overlap. iii) Neutral section. iv) Section insulator.

Last Answer : Ans: i) Insulated overlap: To isolate for operation and maintenance of OHE if two lengths of OHE belong to two elementary sections. Located at feeding posts, sub sectioning posts and booster sections.  ... elementary section. Located at cross over from one track to other, from main line to siding.

Description : State the function of (i) Neutral section, (ii) Section insulator, (iii) Un-insulated overlap, (iv) Insulated overlap.

Last Answer : i) Neutral section: Passing of pantograph under insulated overlap will cause short circuit between two phases of the supply system, damaging OHE & pantograph. To avoid this bridging of two ... belong to two elementary sections. Located at feeding posts, sub sectioning posts and booster sections.

Description : Give protection scheme used for 25kV catenary protection for AC traction.

Last Answer : Protection Scheme Used for 25kV Catenary Protection for AC Traction: As shown in the figure below the scheme consists of 1) MHO relay that makes use of the impedance phase angle to get proper ... adjustment. 2) Over current relay. 3) Under voltage relay for low voltage protection.

Description : Give any four advantages of voice frequency signaling over DC signaling system. 

Last Answer : Advantages of Voice Frequency Signaling Over DC Signaling System: 1. Large number of circuits can be easily derived over a single pair of wires (single pair can control 18 stations). 2. Signal ... used over long distances. 5. Can be used where large number of equipment can be controlled. 

Description : Give any four advantages of remote control system.

Last Answer : Advantages of remote control system: 1. As substations and control posts are unattended (due to remote controls) there is considerable savings due to less manpower. 2. Central control station ... Switching operations are carried out safely, quickly, and economically. 6. Maintenance cost is low.

Description : Explain with neat sketch overload protection for power circuit of locomotive.

Last Answer : Overload Protection for Power Circuit of Locomotive:  1. To protect the main power circuit from overload, the thermal overload relays are used. 2. The overload is sensed by the ... overload relay OLR3 operates for overload fault on traction motor due to the flashover of traction motors. 

Description : Explain protection of locomotive from overvoltage and under voltage

Last Answer : Protection of Locomotive From Overvoltage and Under Voltage: 1. For protection against over voltages the over voltage relay which is basically a potential transformer (PT) is used. 2. ... a relay triggering an alarm, which enables the power controller to react and take corrective measures.

Description : Explain the surge protection of electric locomotive from i) Direct lightening stroke ii) Switching surges

Last Answer : i)Protection of Electric Locomotive From Direct Lightening Stroke:  1. The direct lightning strokes may strike on the overhead conductor on the roof of the locomotive. 2. To protect the ... reduce the steepness of the wave front and also help to absorb the energy in the resistance.

Description : Explain with neat diagram i) Sectioning and paralleling post ii) Sub sectioning post

Last Answer : i) Sectioning and Paralleling Post: Explanation of Sectioning and Paralleling Post: 1. The power supply arrangement is as shown in above figure for two track lines between feeding posts and ... subsection or the other. 4. There is no interrupter for paralleling the up and down track line

Description : List different types of signals. State application of each.

Last Answer : Different Types of Signals: 1) Flag signals: This is shown by signalman if green flag is raised; it means to proceed with caution. Green flag shown down, it means there is track defect; ... green lamps indicate indications as in the 2-aspect system, and the yellow lamp shows the caution indication.

Description : State four important features of LEM that differ it from normal electric motor. 

Last Answer : Important Features of LEM That Differ it From Normal Electric Motor: 1. In LEM, primary & secondary or stator & rotor have longitudinal arrangement while normal electric motor has circular ... in high speed levitated system while normal electric motor is used for rotary mechanical output.

Description : Write down the circuit breaker with their rating used in traction substation. Explain any one.

Last Answer : Circuit Breaker With Their Rating Used in Traction Substation: Rated capacity of a circuit breaker is 750Amps at 25 kV, 500MVA. Its overall tripping time is 0.14 seconds composed of 0.04 ... but in case of traction substation application, mostly Minimum Oil Circuit Breaker (MOCB) is preferred.

Description : State any four relays used for catenary protection. State function of each relay.

Last Answer : Relays Used for Catenary Protection: 1. MHO relay: Wrong coupling protection. 2. MHO relay: Over current protection at farthest point. 3. Over current relay: Over current protection against faults near substation 4. Under voltage relay: Protection against faults far away from substation. 

Description : List any four current collectors for overhead system. State application of each.

Last Answer : Current Collectors for Overhead System With Their Application: 1. Trolley (Pole) collector: It is used for trolley buses having speed range from 20kmph to 32kmph. 2. Cable collector: This ... used for main line service locomotives, urban trains, suburban trains etc. having higher speed range.

Description : List any four weaknesses of LIM propelled railway traction system.

Last Answer : Weaknesses of LIM Propelled Railway Traction System: 1. The system requires looping of all reaction rails all along the route. This considerably adds to the cost of track. 2. Since Al is relative ... in the magnetic and electric circuits at entry and exit ends of motor, poor motor efficiency.

Description : Explain with neat diagram trolley collector for overhead system

Last Answer : Trolley Collector for Overhead System:  This consists of a grooved gun metal wheel or grooved slider shoe with carbon insert carried attached to the end of a long pole provided on the top of ... gives rise to high current density. Suitable for comparative low speed (say 22 to 30 kmph).

Description : Draw and explain in brief construction of Diamond Pantograph. Write one advantage and one disadvantage of it.

Last Answer : Diamond Pantograph: Construction of Diamond Pantograph: 1)Diamond Pantograph consist of pressed steel channel sectional fitted with renewable collector strips and supported at the apex of Pentagonal ... It requires more maintenance than Faiveley type. 4. It is costlier than Faiveley type.

Description : With neat sketch explain automatic weight tension and temperature compensation.

Last Answer : Automatic Weight Tension and Temperature Compensation: The tension in overhead lines in traction systems depends on the temperature. Higher temperatures lead to expansion of conductors and hence sag. It is therefore ... figure. The tension in the contact wire and catenary is around 1000 kg.

Description : Explain the following - 1) Encumbrance 2) Span length.

Last Answer : Encumbrance: It is the axial distance between catenary and contact wire. Its value is maintained at 1.4 m as per rules except at i) Turn outs, ii) Overlaps iii) In the vicinity of over ... depends various factors like: i) Wind pressure ii) Curvatures iii) Current collection point of view etc.

Description : State the classification of locomotive.

Last Answer : Classification of Locomotive:  A) Based on the types of service rendered:  1. Freight service for transportation of goods only.  2. Passenger service for transportation of passengers.  3. Mixed traffic ... the type of supply used:  1. Alternating current (AC)  2. Direct current (DC)

Description : The maximum magnitude of shear stress due to shear force F on a rectangular section of area A at  the neutral axis, is  (A) F/A (B) F/2A (C) 3F/2A (D) 2F/3A

Last Answer : (C) 3F/2A

Description : Pick up the correct statement from the following:  (A) The bending stress in a section is zero at its neutral axis and maximum at the outer fibres  (B) The shear stress is zero at the outer ... (C) The bending stress at the outer fibres, is known as principal stress  (D) All the above 

Last Answer : (D) All the above 

Description : If M, I, R, E, F, and Y are the bending moment, moment of inertia, radius of curvature, modulus of  elasticity stress and the depth of the neutral axis at section, then  (A) M/I = R/E = F/Y (B) I/M = R/E = F/Y (C) M/I = E/R = E/Y (D) M/I = E/R = Y/F

Last Answer : (C) M/I = E/R = E/Y

Description : At any point of a beam, the section modulus may be obtained by dividing the moment of inertia of  the section by  (A) Depth of the section  (B) Depth of the neutral axis  (C) Maximum tensile stress at the section  (D) Maximum compressive stress at the section

Last Answer : (B) Depth of the neutral axis 

Description : Pick up the correct statement from the following:  (A) In a loaded beam, the moment at which the first yield occurs is called yield moment (B) In a loaded beam, the moment at which the ... beam, the neutral axis divides the section in two sections of  equal area  (D) All the above 

Last Answer : (D) All the above 

Description : The yield moment of a cross section is defined as the moment that will just produce the yield  stress in  (A) The outer most fibre of the section  (B) The inner most fibre of the section  (C) The neutral fibre of the section  (D) The fibre everywhere 

Last Answer : (A) The outer most fibre of the section 

Description : The neutral axis of a beam cross-section must (A) Pass through the centroid of the section (B) Be equidistant from the top of bottom films (C) Be an axis of symmetry of the section (D) None of these

Last Answer : (A) Pass through the centroid of the section

Description : When a rectangular beam is loaded transversely, the maximum compressive stress develops on (A) Bottom fibre (B) Top fibre (C) Neutral axis (D) Every cross-section

Last Answer : (B) Top fibre

Description : In a beam, the neutral plane  (A) May be its centre  (B) Passes through the C.G. of the area of cross-section  (C) Does not change during deformation  (D) None of these 

Last Answer : (C) Does not change during deformation

Description : The intensity of direct longitudinal stress in the cross-section at any point distant r from the neutral axis, is proportional to (A) r (B) 1/r (C) r2 (D) 1/r²

Last Answer : (A) r

Description : If is the shear force at a section of an I-joist, having web depth and moment of inertia about its neutral axis, the difference between the maximum and mean shear stresses in the web is, (A) Sd²/8I (B) Sd²/12I (C) Sd²/16I (D) Sd²/24I

Last Answer : (D) Sd²/24I

Description : The shear force on a simply supported beam is proportional to (A) Displacement of the neutral axis (B) Sum of the forces (C) Sum of the transverse forces (D) Algebraic sum of the transverse forces of the section

Last Answer : (D) Algebraic sum of the transverse forces of the section

Description : Pick up the incorrect statement from the following. The intensity of horizontal shear stress at the elemental part of a beam section, is directly proportional to (A) Shear force (B) Area of the section ... . of the area from its neutral axis (D) Moment of the beam section about its neutral axis

Last Answer : Answer: Option D

Description : With usual notations the depth of the neutral axis of a balanced section, is given by (A) mc/t = (d - n)/n (B) t/mc = (d - n)/n (C) t/mc = (d + n)/n (D) mc/t = n/(d - n)

Last Answer : Answer: Option D

Description : If the permissible stress in steel in tension is 140 N/mm², then the depth of neutral axis for a singly reinforced rectangular balanced section will be (A) 0.35 d (B) 0.40 d (C) 0.45 d (D) Dependent on grade of concrete also

Last Answer : Answer: Option B

Description : For a reinforced concrete section, the shape of shear stress diagram is (A) Wholly parabolic (B) Wholly rectangular (C) Parabolic above neutral axis and rectangular below neutral axis (D) Rectangular above neutral axis and parabolic below neutral axis

Last Answer : Answer: Option C

Description : The neutral axis in a T-beam section falls (a) Within the flange (b) Outside the flange (c) Either (a) or (b) (d) All the above

Last Answer : (c) Either (a) or (b)

Description : The section of the beam having greater width at the top in comparison to the width below neutral axis is known as. (a) Critical section (b) T-section (c) L-section (d) None of these

Last Answer : (b) T-section

Description : For a reinforced concrete beam section, the shape of shear stress diagram is (a) Parabolic over the whole section with maximum value at the neutral axis. (b) Parabolic above the neutral axis and rectangular below the neutral axis. (c) Linearly varying as the distance form the N.A. (d) All the above.

Last Answer : (b) Parabolic above the neutral axis and rectangular below the neutral axis.

Description : Regarding the working stress design of under reinforced concrete section, (a) The neutral axis depth will be greater than that of a balanced section. (b) The stress in steel intension will reach ... on the tension side is also be considered for calculating the moment of resistance of the section.

Last Answer : both b&c

Description : The effective depth of a singly reinforced rectangular beam is 300mm. the section is over-reinforced and the neutral axis is 120mm below the top. If the maximum stress attained by concrete is 5N/mn2 and the modular ratio ... in the steel will (a) 130N/mm2 (b) 135N/mm2 (c) 160N/mm2 (d) 180N/mm2

Last Answer : (b) 135N/mm2

Description : The neutral axis of an over –reinforced section falls (a) On the critical neutral axis of balanced section. (b) Below the critical neutral axis of balanced section (c) Above the neutral axis o balanced section (d) Al l the above

Last Answer : (b) Below the critical neutral axis of balanced section

Description : The neutral axis of a balanced section is called (a) Balanced neutral axis (b) Critical neutral axis (c) Equivalent neutral axis (d) All of these

Last Answer : (b) Critical neutral axis

Description : The actual neutral axis of n under reinforced section is above the critical neutral axis of a balanced section (a) Correct (b) Incorrect (c) Not known (d) None of these

Last Answer : (a) Correct

Description : The depth of neutral axis for a balanced section is --------- the depth of critical neutral axis [ A ] equal [ B ] always greater than [ C ] always less than [ D ] may be sometimes greater than

Last Answer : [ A ] equal

Description : The depth of neutral axis for over reinforced section is ----------- the depth of critical neutral axis [ A ] Equal to [ B ] Greater than [ C ] Less than [ D ] None of the above

Last Answer : [ B ] Greater than

Description : The depth of neutral axis for under reinforced section is --------- the depth of critical neutral axis [ A ] Equal to [ B ] Greater than [ C ] Less than [ D ] None of the above

Last Answer : [ C ] Less than

Description : The neutral axis corresponding to balanced section condition is termed as [ A ] Critical neutral axis [ B ] Centroidal neutral axis [ C ] Balanced neutral axis [ D ] All the above

Last Answer : [ A ] Critical neutral axis

Description : A beam of T-section is subjected to a shear force of F. The maximum shear force will occur at the a. top of the section b. bottom of the section c. neutral axis of the section d. junction of web and flange

Last Answer : c. neutral axis of the section