Air Conditioning for Railway Coaches
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Questions and Answers

What is the cooling capacity of the new roof-mounted AC units per coach?

  • 5.2 TR
  • 14.0 TR (correct)
  • 7.0 TR
  • 10.4 TR

    • How do the compressors in the new AC units operate under normal conditions?

  • All four compressors operate simultaneously.
  • One compressor operates; others are completely shut down.
  • Three compressors operate, with the fourth as a standby. (correct)
  • Compressors run at reduced capacity.

    • What type of compressors are used in the modular roof-mounted AC units?

  • Open compressors
  • Reciprocating compressors
  • Centrifugal compressors
  • Hermetically sealed compressors (correct)

    • What is the primary purpose of the new roof-mounted AC units in railway coaches?

    <p>To improve energy efficiency and comfort.</p> Signup and view all the answers

    What is the power requirement of the roof-mounted units under normal conditions?

    <p>11.5 KW</p> Signup and view all the answers

    What method is used to start the compressors to reduce electric peak demand?

    <p>Sequence with time delay</p> Signup and view all the answers

    Which type of coaches on Indian Railways utilizes a brushless alternator for power supply?

    <p>Self-generating coaches</p> Signup and view all the answers

    What was identified as a significant cause for excessive vibration in discharge pipes?

    <p>Defective packless vibration eliminator</p> Signup and view all the answers

    Which modification was NOT implemented to address vibration issues?

    <p>Introducing flexible mounting pads</p> Signup and view all the answers

    What was determined to be the major contributing factor to water ingress due to rain?

    <p>Inadequate drainage area</p> Signup and view all the answers

    What change was made to address the problem of packing dislodging due to vibrations?

    <p>Implementing a single gasket under point pressure</p> Signup and view all the answers

    What issue was directly related to condensate water entering the corridor?

    <p>Evaporator section not being water tight</p> Signup and view all the answers

    What is the primary power source for coaches at low speeds and during halts?

    <p>110 V lead acid battery</p> Signup and view all the answers

    What voltage and phase is supplied by the diesel-generating sets in End-On-Generation coaches?

    <p>415/750 V, three phase</p> Signup and view all the answers

    Which component of the air conditioning system is NOT mounted on the underframe of the coach?

    <p>Cooling coils</p> Signup and view all the answers

    What is a major drawback of the conventional AC system mentioned?

    <p>Refrigerant leakage</p> Signup and view all the answers

    How much weight reduction does the roof-mounted AC package unit contribute compared to the conventional unit?

    <p>900 Kg</p> Signup and view all the answers

    What advantage does the roof-mounted AC unit provide in terms of fuel consumption?

    <p>Saves fuel for hauling</p> Signup and view all the answers

    How is the roof-mounted AC unit installed in the coach?

    <p>Lowered into the false ceiling and connected</p> Signup and view all the answers

    What benefit does the roof-mounted AC unit provide in terms of operational costs?

    <p>It pays for itself within a year</p> Signup and view all the answers

    What is NOT a feature of the air conditioning system in Indian Railways coaches?

    <p>External cooling units</p> Signup and view all the answers

    What is the maximum refrigerant charge for the roof-mounted A.C. unit?

    <p>3 Kg</p> Signup and view all the answers

    What advantage does the hermetically sealed system have over a conventional A.C. system?

    <p>Lower potential for gas leakages.</p> Signup and view all the answers

    How long does it take to replace a defective roof-mounted A.C. unit?

    <p>Two hours</p> Signup and view all the answers

    Which refrigerant is used in the roof-mounted A.C. unit?

    <p>R-22</p> Signup and view all the answers

    What is a benefit of the roof-mounted A.C. unit being installed on the roof?

    <p>Negligible dirt or dust collection.</p> Signup and view all the answers

    What is the weight difference between the roof-mounted A.C. unit and the conventional A.C. unit?

    <p>Roof-mounted is lighter by 1800 Kg</p> Signup and view all the answers

    How does the roof-mounted A.C. unit control humidity during monsoons?

    <p>By a microprocessor-based control system.</p> Signup and view all the answers

    What disadvantage does the conventional A.C. system have in comparison to the roof-mounted unit?

    <p>More maintenance required.</p> Signup and view all the answers

    What is a key feature of the roof-mounted A.C. unit that enhances its reliability?

    <p>Use of 3ph AC motors.</p> Signup and view all the answers

    What performance metric is described as 'Nil' for roof-mounted A.C. units?

    <p>Damage due to flash floods</p> Signup and view all the answers

    Which type of A.C. unit has the latest technology?

    <p>Roof mounted</p> Signup and view all the answers

    What is the range of capacity control for roof-mounted A.C. units?

    <p>25% to 100%</p> Signup and view all the answers

    What significant problem is associated with roof-mounted A.C. units?

    <p>Failure of safety cut-outs</p> Signup and view all the answers

    For which factor is the downtime for repair shorter with roof-mounted A.C. units compared to conventional units?

    <p>Unit replacement time</p> Signup and view all the answers

    What is a consequence of poor maintenance for conventional A.C. units?

    <p>Deterioration due to dust collection</p> Signup and view all the answers

    Which A.C. unit type tends to take in toilet smells?

    <p>Conventional</p> Signup and view all the answers

    What is one of the major problems noted for roof-mounted A.C. units?

    <p>Water ingress into the corridor</p> Signup and view all the answers

    Which reason contributed to gas leakage in one particular make of A.C. unit?

    <p>Lack of vibration testing</p> Signup and view all the answers

    What is the downtime for repairs of conventional A.C. units described as?

    <p>Very long</p> Signup and view all the answers

    What modification was made to address the issue of vibrations caused by the compressor mounting?

    <p>Secure the compressor at the top with solid mounting pads</p> Signup and view all the answers

    What was identified as a primary cause of water ingress due to rain?

    <p>Ineffective drainage area</p> Signup and view all the answers

    How was the issue of packing dislodging due to vibrations addressed in the design modifications?

    <p>Introduced a single gasket under point pressure mounting</p> Signup and view all the answers

    What contributes to the problem of condensate water entering the corridor?

    <p>Condensate carried by the blower into the duct</p> Signup and view all the answers

    What factor was significantly improved to reduce the risk of water ingress through the interface between the trough and the package?

    <p>Apply a single gasket design with skirting</p> Signup and view all the answers

    What is the main advantage of the roof-mounted AC units compared to the traditional AC systems used in railway coaches?

    <p>They are more energy efficient and reliable during operation.</p> Signup and view all the answers

    What component of the roof-mounted AC units serves as a standby during peak days of the summer?

    <p>The compressors in the unit.</p> Signup and view all the answers

    Which system must the roof-mounted AC unit be compatible with for operation?

    <p>E.O.G. systems or S.G. systems.</p> Signup and view all the answers

    How are the compressors in the roof-mounted AC units started to manage electricity demand?

    <p>Compressors are started in sequence with time delays.</p> Signup and view all the answers

    What characterizes the compressors used in the modular type roof-mounted AC units?

    <p>They are specially developed for dynamic conditions.</p> Signup and view all the answers

    What is the approximate electrical requirement of the roof-mounted AC unit under normal conditions?

    <p>11.5 KW at 20 amperes.</p> Signup and view all the answers

    How many compressors are used in each modular AC unit fitted in railway coaches?

    <p>Two compressors.</p> Signup and view all the answers

    What is the primary reason for the failure of the AC control panel in roof-mounted units?

    <p>Vibration tests not conducted</p> Signup and view all the answers

    Which maintenance issue is noted as significant for conventional AC units?

    <p>Deterioration from dust collection</p> Signup and view all the answers

    What is identified as a shortcoming specific to roof-mounted AC package units?

    <p>Water ingress into the corridor</p> Signup and view all the answers

    How does the capacity control range of roof-mounted AC units compare to conventional units?

    <p>Higher within a smaller range</p> Signup and view all the answers

    What type of air intake does the roof-mounted AC unit utilize?

    <p>From the roof, avoiding restroom smells</p> Signup and view all the answers

    What is a notable performance characteristic for roof-mounted AC units compared to conventional units?

    <p>Excellent performance overall</p> Signup and view all the answers

    What is the average downtime required to repair a roof-mounted AC unit?

    <p>4 hours for unit replacement</p> Signup and view all the answers

    What issue is linked to cows causing heavy damage?

    <p>Physical damage to the AC structure</p> Signup and view all the answers

    What is the primary benefit of the roof-mounted AC package units compared to conventional units?

    <p>Is lighter and saves fuel for hauling</p> Signup and view all the answers

    What consequence does dust collection have on the conventional AC unit's performance?

    <p>Quick deterioration of performance</p> Signup and view all the answers

    What characteristic does the latest technology in AC units possess?

    <p>Features multiple compressors for better capacity control</p> Signup and view all the answers

    Which of the following issues is highlighted as a drawback of conventional AC systems?

    <p>Heavy equipment weight</p> Signup and view all the answers

    In terms of installation, what is a characteristic feature of the roof-mounted AC units?

    <p>Can be installed without specialized tools</p> Signup and view all the answers

    What total weight reduction does the implementation of roof-mounted AC units provide for 20 coaches?

    <p>36 MT</p> Signup and view all the answers

    What is a major advantage of the hermetically sealed system used in roof-mounted AC units?

    <p>Minimized refrigerant leakage</p> Signup and view all the answers

    What requirement is met by the traditional power source for coaches at low speeds and halts?

    <p>Utilization of a 110 V lead acid battery</p> Signup and view all the answers

    Which of the following is part of the air conditioning system found in Indian Railways coaches?

    <p>Open type compressor with a blower fan</p> Signup and view all the answers

    What is the voltage and phase supplied by diesel-generating sets in End-On-Generation coaches?

    <p>415/750 V, 3 phase</p> Signup and view all the answers

    Which aspect of the roof-mounted AC package units contributes to their lower operational costs?

    <p>Low cost of installation and maintenance</p> Signup and view all the answers

    What is the refrigerant used in the roof-mounted A.C. unit?

    <p>R-22</p> Signup and view all the answers

    What is the maximum refrigerant charge for the conventional A.C. unit?

    <p>15-20 Kg</p> Signup and view all the answers

    What is a primary advantage of the hermetically sealed system in roof-mounted A.C. units?

    <p>Reduced potential for gas leaks and breakdowns</p> Signup and view all the answers

    Which statement accurately describes the installation time for roof-mounted A.C. units compared to conventional units?

    <p>Roof-mounted units take 4 hours while conventional units take 4 days</p> Signup and view all the answers

    What is a major drawback identified for conventional A.C. units?

    <p>Potential for water leakage</p> Signup and view all the answers

    What feature of the roof-mounted A.C. unit helps to minimize dirt and dust accumulation?

    <p>Location on the roof</p> Signup and view all the answers

    What is the approximate weight difference between the roof-mounted A.C. unit and the conventional A.C. unit?

    <p>900 Kg</p> Signup and view all the answers

    What component contributes to the low maintenance of the roof-mounted A.C. unit?

    <p>Absence of commutators and brushes</p> Signup and view all the answers

    Which factor enhances the A.C. unit's reliability and reduces breakdowns?

    <p>Hermetically sealed system with no openings</p> Signup and view all the answers

    What is the minimum cooling capacity required for each roof-mounted A/C unit per coach?

    <p>20,000 K.Cal/hr</p> Signup and view all the answers

    Which refrigerant is specified for use in the A/C package unit?

    <p>R22</p> Signup and view all the answers

    What type of compressor motor is used in the A/C units?

    <p>Hermetic</p> Signup and view all the answers

    What is the rated current consumption of the compressor at 415V?

    <p>8.25 Amps</p> Signup and view all the answers

    What is the diameter of the condenser fan used in the A/C units?

    <p>533.4 mm</p> Signup and view all the answers

    What is the face area of the condenser coil in square meters?

    <p>0.67 M2</p> Signup and view all the answers

    What is the specified power factor of the compressor motor?

    <p>0.8</p> Signup and view all the answers

    Which material is used for the tubes in the condenser coil?

    <p>Copper</p> Signup and view all the answers

    What is the airflow rate of the condenser fan in CFM?

    <p>5000 CFM</p> Signup and view all the answers

    What is the refrigerant charge limit for each circuit in the A/C unit?

    <p>3.0 Kg</p> Signup and view all the answers

    What feature of the branch diffuser allows for control of cool air quantity?

    <p>Adjustable vanes</p> Signup and view all the answers

    How is the power supply for lighting and fan loads transformed in the coach?

    <p>415/190V transformer</p> Signup and view all the answers

    Which voltage is supplied to the water raising apparatus in the coach?

    <p>240V AC</p> Signup and view all the answers

    What type of panel is provided inside the coach for distribution of the electrical system?

    <p>Control panel</p> Signup and view all the answers

    What is the specification of the emergency lighting battery provided in the coach?

    <p>24V, 90AH</p> Signup and view all the answers

    What type of transformer unit is used for charging the emergency lighting battery?

    <p>Charging transformer rectifier</p> Signup and view all the answers

    What is the electrical configuration of the feeders supplying the coach?

    <p>Three-phase, 4 wire</p> Signup and view all the answers

    Which arrangement is used to connect adjacent coaches for power transmission?

    <p>Inter vehicular couplers</p> Signup and view all the answers

    What does the 415V, 3-phase supply provide for the railway coaches?

    <p>Light and fan loads</p> Signup and view all the answers

    How many parts does the transverse berth's diffuser consist of?

    <p>Two parts</p> Signup and view all the answers

    What is the primary purpose of providing fresh air at a rate of 0.35 m³/min per person in the A.C. compartment?

    <p>To maintain air quality</p> Signup and view all the answers

    What is the nominal current consumption of the evaporator blower fan motor at 415V, 3ph, 50Hz, AC?

    <p>2.2 Amps</p> Signup and view all the answers

    What type of protection does the condenser motor conform to in terms of IP rating?

    <p>IP 55</p> Signup and view all the answers

    What is the range of RPM for the motors mentioned in the specifications?

    <p>1400 +/- 10%</p> Signup and view all the answers

    What material is specified for the fins of the evaporator unit?

    <p>Aluminium</p> Signup and view all the answers

    What is the specified face area for the evaporator unit?

    <p>0.265 m²</p> Signup and view all the answers

    How many fins per centimeter does the evaporator unit have, considering the allowable margin?

    <p>4.3 +/- 1</p> Signup and view all the answers

    What is the air flow rate in CFM for the evaporator fan?

    <p>2000 CFM</p> Signup and view all the answers

    What is the external static pressure with which the fan operates?

    <p>20 mm water gauge</p> Signup and view all the answers

    What is the thickness of the fins used in the evaporator unit?

    <p>0.19 mm</p> Signup and view all the answers

    Study Notes

    Roof Mounted Air-Conditioning Package Units for Railway Coaches

    • Roof-mounted AC units for Indian Railways coaches offer more comfort and allow for more coaches on superfast trains (e.g., Rajdhani Expresses).
    • These new units are more efficient and lightweight, manufactured domestically.
    • Two high-capacity (minimum 7.0 TR cooling) packaged units replace the previous underframe units (5.2 TR each).
    • The new units are placed above the toilets on both ends of the coach, supplying conditioned air throughout.
    • Four compressors are fitted per unit, but typically three operate, with one as a backup for peak summer demand.
    • This advanced system is more energy-efficient and reliable than existing open systems.
    • The units are suitable for both electric-originated generation (EOG) and self-generating (SG) coach systems.

    Existing Systems

    • Current systems use open-type compressors, creating refrigerant leakage and maintenance issues, along with higher energy consumption.
    • Self-generating (SG) coaches use axle-driven alternators, generating 110V DC power, supplementing with batteries for low speeds and halted operation.
    • End-On-Generation (EOG) coaches use diesel-generating sets for power. These sets operate at 415/750 V, 3 phase, 50 Hz AC and power the train and distributed through feeders.

    Roof-Mounted AC Package Unit Features

    • Lightweight (~900 kg) compared to traditional units (~2700 kg)
    • Faster installation (4 hours) versus traditional systems
    • Environmentally friendly refrigerant (R-22 or R-134A, lower than 3kg)
    • Less dust/dirt build-up, lower maintenance due to roof-mounted position
    • Protected from flood damage
    • Less likely to be damaged from cattle moving about.

    Performance Comparison

    • Roof-mounted units significantly outperform conventional units.
    • Key performance indicators for roof-mounted units highlight improved performance in comparison with conventional units

    Performance Issues and Solutions

    • Gas leakage, water ingress, and tripping of packages are common issues with current systems.

    • Problems in control panel components and switchgear lead to problems.

    • Solutions include:

      • Improved design for better water drainage
      • Increased robustness for vibration control
      • Standardization of control panel designs
      • Upgrade to better quality components.

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    Related Documents

    Roof Mounted Air-Conditioning Package Units for Railway Coaches PDF
    A/C 3Tier Sleeper Coach PDF

    Description

    Explore the advancements in roof-mounted air-conditioning units for Indian Railways coaches. This quiz covers the efficiency, design, and technology behind the new systems replacing older models. Dive into details about their cooling capacity and energy-saving features.

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