LHB Coach Air-Conditioning Overview
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Questions and Answers

Which company is NOT mentioned as a manufacturer of the RMPU used in LHB coaches?

  • Fedder Lloyd
  • CoolTech Systems (correct)
  • Sidwal
  • Amit Engineering

    • What type of air-conditioning system is utilized in LHB coaches?

  • Centrifugal chiller system
  • Evaporative cooling system
  • Natural ventilation system
  • Micro-processor controlled air-conditioning system (correct)

    • Which function is NOT provided by the air-conditioning system in LHB coaches?

  • Air purification (correct)
  • Air filtration
  • Air dehumidification
  • Air heating

    • How many air-conditioning units are provided in LHB coaches?

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

    Which area is NOT mentioned as part of the ventilation system for LHB coaches?

    <p>Storage room</p> Signup and view all the answers

    What is the primary design basis for the LHB coaches' air-conditioning system?

    <p>Design from M/S ALSTHOM LHB</p> Signup and view all the answers

    What does RMPU stand for in the context of LHB coaches?

    <p>Roof Mounted Package Unit</p> Signup and view all the answers

    What feature of the air-conditioning system handles excess moisture?

    <p>Air dehumidification</p> Signup and view all the answers

    What is the primary function of the compact air conditioning unit in LHB coaches?

    <p>To condition air for passenger comfort</p> Signup and view all the answers

    How is the outside air mixed with recirculating air in the compact air conditioning unit?

    <p>By adjusting the positions of air dampers</p> Signup and view all the answers

    Which assembly is NOT part of the AC system for the Passenger and Generator cars?

    <p>Heating element unit</p> Signup and view all the answers

    What is the role of the axial fans in the compact air conditioning unit?

    <p>To assist in the condensing process</p> Signup and view all the answers

    In the preheating and cooling operation mode, what is done to the outside air dampers?

    <p>They are closed to enable quicker temperature adjustment</p> Signup and view all the answers

    What ensures the fresh air volume of 21 m3/h per person in normal operation mode?

    <p>Automated positioning of dampers</p> Signup and view all the answers

    What components are included in the two separate cooling circuits of the compact air conditioning unit?

    <p>Two hermetic refrigeration compressors and two condensers</p> Signup and view all the answers

    What type of filters are part of the compact air conditioning unit?

    <p>Mixed air filters</p> Signup and view all the answers

    Where is the compact air conditioning unit installed in LHB coaches?

    <p>In a recessed trough matching the car profile</p> Signup and view all the answers

    What does the exhaust air system primarily help to manage?

    <p>Removal of stale air</p> Signup and view all the answers

    What occurs when the cooling power request is received in the cooling circuit?

    <p>A safety check is performed before turning on the compressor.</p> Signup and view all the answers

    What happens to the adjusting dampers when the AC system fails due to a power supply failure?

    <p>They close to operate with outside air.</p> Signup and view all the answers

    Which component in the air conditioning system sucks air from the mixing chamber?

    <p>The supply air fan.</p> Signup and view all the answers

    What is the room set point temperature in winter mode for a selection of 24.0°C?

    <p>21.0°C</p> Signup and view all the answers

    In which operational mode does the system use a dedicated service program for testing?

    <p>Test mode.</p> Signup and view all the answers

    At what relative humidity does the dehumidification function activate?

    <p>60%</p> Signup and view all the answers

    How long does the test mode run before it has to be reset?

    <p>2 hours.</p> Signup and view all the answers

    What is introduced when the moisture sensor indicates less than 60% relative humidity during dehumidification?

    <p>The extra heater continues operation.</p> Signup and view all the answers

    Where is the 110V supply located in the controller?

    <p>On a front side connector of card A1.</p> Signup and view all the answers

    What maximum percentage of cooling output is allowed during dehumidification service?

    <p>50%</p> Signup and view all the answers

    What command is used to switch to test mode during the testing process?

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

    What is one function of the condenser fans in the AC unit?

    <p>They suck fresh air through ventilation slots.</p> Signup and view all the answers

    What initiates the emergency mode in the air conditioning system?

    <p>Failure of the power supply.</p> Signup and view all the answers

    What is the primary purpose of the compensating chamber?

    <p>To distribute air into the passenger compartment.</p> Signup and view all the answers

    What does the software command 'Z' accomplish during the test mode?

    <p>It sets or resets outputs.</p> Signup and view all the answers

    What happens when a measuring sensor fails in the system?

    <p>Evaluation is taken over by the sensor of another system.</p> Signup and view all the answers

    Which fixed value is used when the set point generator is defective?

    <p>23 degrees C</p> Signup and view all the answers

    In pre-heating mode, how long must the output be active for the flap to fully open?

    <p>At least 90 seconds</p> Signup and view all the answers

    What mode does the system switch to after achieving an indoor temperature of 14ºC during pre-heating?

    <p>Heating in controlled service mode</p> Signup and view all the answers

    What is the initial condition to start pre-cooling mode?

    <p>When the room temperature is above 28ºC</p> Signup and view all the answers

    What does the system use to save energy in both pre-heating and pre-cooling modes?

    <p>100% recirculating air</p> Signup and view all the answers

    What occurs when both room and duct sensors are defective?

    <p>The system turns off heating and cooling.</p> Signup and view all the answers

    Which component controls the air-conditioning units in controlled service mode?

    <p>A microcomputer</p> Signup and view all the answers

    What is the purpose of the exhaust air fan in pre-heating mode?

    <p>It must not be running.</p> Signup and view all the answers

    When does the cooling system switch to controlled service mode during pre-cooling?

    <p>When the room temperature reaches 28ºC</p> Signup and view all the answers

    What temperature range is set for summer mode with the 7-point temperature selector switch?

    <p>20.0°C to 24.0°C</p> Signup and view all the answers

    What is the purpose of the moisture sensor during the dehumidification function?

    <p>To detect relative humidity levels</p> Signup and view all the answers

    When does the extra heater become activated during dehumidification?

    <p>When cooling power is insufficient to maintain temperature</p> Signup and view all the answers

    What action is taken when a cooling power request is received?

    <p>A safety check is conducted prior to compressor activation</p> Signup and view all the answers

    What is the maximum allowed cooling output during dehumidification service?

    <p>50%</p> Signup and view all the answers

    Which of the following statements correctly describes the air-conditioning units in LHB coaches?

    <p>All units used in different car types are identical.</p> Signup and view all the answers

    What is the primary purpose of the roof-mounted AC package unit used in LHB coaches?

    <p>To facilitate air filtering and air dehumidification.</p> Signup and view all the answers

    In which of the following areas is the concentrated heating function of the air-conditioning system NOT incorporated?

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

    What task is NOT performed by the AC systems in LHB coaches?

    <p>Air pollution measurement</p> Signup and view all the answers

    Which component is essential for maintaining the optimal air quality in the LHB coaches?

    <p>Air filter</p> Signup and view all the answers

    How many compact air-conditioning units do the generator cars of LHB coaches have?

    <p>One unit each</p> Signup and view all the answers

    Which feature of the air-conditioning system is specifically responsible for reducing humidity levels?

    <p>Air dehumidification</p> Signup and view all the answers

    What is the benefit of using micro-processor controlled air-conditioning systems in LHB coaches?

    <p>They allow for automatic adjustments based on environmental changes.</p> Signup and view all the answers

    What is the controlled factor for mixing outside air with recirculating air in the compact air conditioning unit?

    <p>Air dampers</p> Signup and view all the answers

    Which component is responsible for the supply of air in the compact air conditioning unit?

    <p>Radial fans</p> Signup and view all the answers

    What is the intended fresh air volume per person in normal operating mode of the AC system?

    <p>21 m3/h</p> Signup and view all the answers

    In which mode are the outside air dampers closed to enhance rapid temperature changes?

    <p>Preheating and cooling operation</p> Signup and view all the answers

    Which of the following components is NOT part of the cooling circuits in the compact air conditioning unit?

    <p>Heating elements</p> Signup and view all the answers

    What is the primary function of the exhaust air system in the AC system for LHB coaches?

    <p>Removing excess moisture</p> Signup and view all the answers

    Which sensors are essential components of the AC system in LHB coaches?

    <p>Temperature and humidity sensors</p> Signup and view all the answers

    What maximum percentage of cooling output is permitted during the dehumidification service?

    <p>50%</p> Signup and view all the answers

    What component is designed to prevent excess moisture buildup in the air conditioning system?

    <p>Dehumidification function</p> Signup and view all the answers

    Which operating mode enables a specific service program for system testing?

    <p>Test mode</p> Signup and view all the answers

    What is the primary function of the digital controller in the air conditioning system?

    <p>It manages all controlling and regulating functions.</p> Signup and view all the answers

    In which operational mode does the air conditioning system use a dedicated test program?

    <p>Test mode</p> Signup and view all the answers

    What action occurs when the adjusting dampers of the circulating air duct close?

    <p>The system operates solely with outside air.</p> Signup and view all the answers

    Which component is responsible for sucking air from the mixing chamber in the compact air conditioning unit?

    <p>Supply air fan</p> Signup and view all the answers

    What is indicated by the command 'H' during the testing process?

    <p>Start the test mode.</p> Signup and view all the answers

    What happens to the outputs during the test mode?

    <p>They are switched off completely.</p> Signup and view all the answers

    What is the layout structure of the supply air duct in the compact air conditioning unit?

    <p>Longitudinally split and thermally insulated.</p> Signup and view all the answers

    In emergency mode, what is the main source of air for the air conditioning system?

    <p>Fresh outside air.</p> Signup and view all the answers

    What does the software command 'Z' do during the test mode?

    <p>Resets any output settings.</p> Signup and view all the answers

    What is the primary purpose of the condenser fans during operation?

    <p>To cool the compressor-condenser section.</p> Signup and view all the answers

    What happens in the emergency mode when the room and duct sensors are defective?

    <p>Heating and cooling are turned off, but ventilation continues.</p> Signup and view all the answers

    In which scenario does the system start using recirculating air only in pre-heating mode?

    <p>At an indoor temperature of less than 14ºC.</p> Signup and view all the answers

    What fixed value does the system control to when the set point generator is defective?

    <p>23 degrees C</p> Signup and view all the answers

    What is the maximum duration for which the output must be active in pre-heating to ensure the flap fully opens?

    <p>90 seconds</p> Signup and view all the answers

    Under what condition does pre-cooling mode initiate?

    <p>When the indoor temperature is greater than 28ºC.</p> Signup and view all the answers

    What is the energy-saving strategy employed during both pre-heating and pre-cooling modes?

    <p>Using 100% recirculating air.</p> Signup and view all the answers

    What control mechanism governs the air-conditioning units in controlled service mode?

    <p>A dedicated microcomputer.</p> Signup and view all the answers

    What occurs when the system reaches an indoor temperature of 14ºC during pre-heating?

    <p>Heating switches to controlled service mode.</p> Signup and view all the answers

    What action does the system take if both duct air and room temperature sensors are defective?

    <p>It defaults to a specific temperature setting.</p> Signup and view all the answers

    What fixed value does the system utilize when the duct air temperature sensor is defective?

    <p>20 degrees C</p> Signup and view all the answers

    Study Notes

    LHB Coach Air-Conditioning

    • LHB coaches are manufactured by RCF in Kapurthala using technology licensed from ALSTHOM.
    • Air-conditioning is micro-processor controlled for comfort.
    • Several manufacturers' make RMPU units are used (Sidwal, Fedder Lloyd, Amit Engineering, Lloyd Electric).
    • AC systems are roof-mounted.
    • The system's functions include ventilation, heating, cooling, dehumidification, and air filtering.
    • The system serves passenger and staff compartments, restrooms, and kitchen areas.

    Construction

    • AC units are compact, with two units per coach and one per generator car.
    • Units are identical in different car types.

    Diagram of Control Panel

    • The AC system for passenger and generator cars has these components:
      • Compact air conditioning unit
      • Duct system
      • Exhaust air system
      • WC/WC exhaust fan
      • WC/switch cabinet exhaust fan
      • Circulating air duct system
      • Fresh air screen
      • Open/closed-loop control devices
      • Sensors

    Compact Air-Conditioning Unit

    • The unit has been designed for 2-tier, 3-tier, and chair cars.
    • Fresh air is drawn in through screens and filters.
    • Air is mixed with recirculated air based on computer-controlled dampers.
    • The units are recessed to fit the car's profile.
    • The unit has two cooling circuits:
      • Two hermetic compressors with oil heaters.
      • Two condensers with copper pipes and aluminum fins.
      • Two axial fans for condenser cooling.
      • Two evaporators.
      • Two twin-sucking radial fans for supply air.
      • Three maintenance covers.
      • Two air inlets for circulating air.
      • One air outlet for supply air.
      • Control and safety devices.
      • Pipelines/fittings.
      • Two mixed air filters.

    Operating Modes

    • Preheating/Precooling: Dampers close for quick heating/cooling.
    • Normal Operation: Dampers adjust for 21 m³/h fresh air per person.
    • Emergency Operation: If power fails, the system operates on outside air only.

    Controller

    • The digital controller regulates and controls all functions.
    • It is a rack-mounted system using Eurocard-form factor cards and 19" technology.
    • It has multiple cable connectors for signals and power inputs (e.g., X1, X2).

    Software Operating Modes

    • Operations are separated into Test, Emergency and Control.

    Test Mode

    • The service program PRUEFWIN is used for testing.
    • A PC is connected for testing.
    • Testing mode last for 2 hours.
    • User can test individual functions after testing mode.

    Emergency Mode

    • The system goes into emergency mode if there’s a power problem.
    • Operations are automatically switched to use outside air.

    Temperature Regulation in Preheating and Precooling

    • Preheating involves maximizing heater power until the indoor temp reaches 14 °C, and the system shifts to a controlled heating mode.

    • Energy is saved by using only recirculated air.

    • Fresh air/recirculating air flap is set to extreme position (100% recirculation).

    • The exhaust air fan isn't running during preheating.

    • Precooling involves maximizing cooling output to reach precooling temperature before cooling in controlled mode takes over.

    Pre-heating, Cooling and Dehumidication

    • Controlling is by using a microcomputer and is completely automatic.

    Temperature Regulation in Cooling/Heating Mode

    • Room temperature is controlled by a microcomputer.
    • Predefined set-point temperatures are available for both cooling and heating modes. (Specific values)

    Cooling Circuit Control

    • A safety check is done before starting the compressor for cooling.
    • Thermal monitoring of the condenser fan, suction pressure, and high-pressure messages are available.

    Dehumidification

    • Used when relative humidity increases to 60%.
    • A moisture sensor monitors the humidity.
    • The cooling power is controlled by an extra heater.

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    Air Conditioning in LHB Variants of AC Coaches PDF

    Description

    Explore the air-conditioning systems used in LHB coaches, detailing their components, functions, and construction. This quiz covers the micro-processor controlled systems and the manufacturers involved in producing the RMPU units, along with a diagram of the control panel.

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