Medha Servo Drives Private Limited Ghatkesar, Hyderabad, Telangana

Vigilance Control Device (VCD) is a microcontroller based safety device which will automatically apply penalty brakes in case the driver is incapacitated. Similar operation is available in older locomotives in the form of Deadman’s Lever.

A typical vehicle control system comprises microprocessor based vehicle control unit, associated sensors, distribution boxes, contactors, and display unit with keypad. Based on the application, the hardware and configuration of the system varies.

Station TCS is the network of control unit, radio unit, and an array of passive radio frequency identifier (RFID) tags positioned at all the crucial location s of the station and block section placed in the vicinity of the station. Loco TCS is an onboard control unit connected to a speed sensor, RFID reader, radio unit, and display unit. Loco TCS RFID reader is mounted under frame of the locomotive such that it can read the RFID tags fitted between the rails and collect data like unique tag id, direction of travel, unique track identification number (TIN). This data is communicated to the station TCS through the radio link. Station TCS locates the train in its database, based on the RFID tag ID and sends the information like approaching signal aspect, distance to the locomotive TCS. Loco TCS uses the information provided by the station TCS like approaching signal aspect, movement authority (MA), and collects the speed of the train through sensors mounted on loco axle to determine whether the loco is traveling in safe speed limits. In case, the locomotive is running beyond safe speed an alert is sounded to the loco pilot for 5 seconds before initiating the brakes and bringing the train to a complete stop.

Medha and Traktionssysteme, Austria entered into a Joint Venture agreement (Medha Traction Equipment Pvt. Ltd.) to manufacture 3 phase AC Traction Motors and Traction Alternators in India. Medha Traction Equipment Pvt. Ltd. produces AC Traction motors which complement Medha's existing and growing portfolio of traction and propulsion products. Implemented product range for applications including diesel and electric locomotives, DMU, EMU, Metro, High Speed, Tram and Trolley bus Recently made motors for 1600 HP DMU, 1.3 MW EMU, and 4500 HP diesel locomotive

Diesel locomotive and DMU propulsion system architectures provide rectified alternator output as stable DC link bus voltage input to the Traction Converter. Traction Converter could be a combination of one or more inverters each controlling one or more traction motors.

Driver's display console for Locomotives EMUs Metro Cars for showing running data (status information), historical data (Event Fault logs), maintenance related data and for data entry. The Multifunction TFT LCD Display is used in Locomotives as Man Machine Interface for guiding the operator to control the Locomotive. It communicates with the Locomotive Control System by either RS232 or RS485 link. It displays the data sent by the Locomotive Control System in graphical as well as text format.

Medha is one of the leading manufacturers of speed recorders for railway applications. These recorders are used on locomotives and are similar in function to black boxes in aeroplanes. Speed recorders are used for monitoring the performance of loco driver and especially in the event of an accident the recorded data becomes vital for establishing the cause of accident.

Medha�s Single Section Axle Counter (SSDAC) overcome track circuit limitations in situations including - water logging or flooding, metal bridges, long block sections, yards with poor wheel shunt lines, high EMIEMC environments, tunnels, high temperature and sunshine regions, complex and large stations and yards etc. 2oo2 architecture Detects 2 or 3 points Counts and compares the number of axles entering and exiting the section and establish as if the last car has cleared that section. System is interfaced to provide section occupancy information, based on which signaling system controls safe movement of trains. Configurations (SSDAC) One detection point � Single section (1DP-1S): Typically used for sidings Two detection points � Single section (2DP-1S): Straight line sections Three detection points � Single section (3DP-1S): Point zones. Three detection points � Two consecutive sections or Auto-Section in a straight line (3DP-2SAS

Medha offers HEP units from 300kVA-500kVA and higher (1000kVA – 2x500kVA), utilizing capacities of alternator transformer to meet auxiliary power requirements such as lighting, fans, HVAC, heating, battery charging etc. of complete train. HEPs are IGBT based converters, using sine filters at inverter output to minimize harmonic distortions. Protections for output overload, short circuit and power ground are provided. The converters are designed to suit wide range of inputs.

Features : Energy efficient design and Underframe or on-board mounted

Central interlocking unit (ciu) uses two-out-of-two architecture with two independent channels computing the vital interlocking logic and a supervisory processor monitoring the two vital computing channels. Hot standby with automatic change-over facility is provided. Redundant communication channels to object controller (oc) and panel processor (pp) are provided through two communication processors. Ofc interface with ring configuration is used for communication between ciu and oc and ciu and pp.

Electronic Governor is a maintenance free alternative to the mechanical Governors popularly used for this application. The Governor consists of a Control Unit mounted in the Driver cab, and an Actuator Unit mounted on the Engine. The Actuator Unit can be mounted exactly on the same Engine base as mechanical Governors. The Governor controls the engine speed, based on throttle handle position (popularly known as notch) selected by the Driver on the Driver Desk. Engine RPM is measured from a Tachogenerator or speed sensor mounted on the Engine. Digital PID control is used to calculate desired fuel rack position dynamically, based on the selected notch on throttle handle and measured Engine RPM. A Stepper motor drive is used in the Actuator Unit to control the fuel rack of Diesel Engine

Medha supplies driver consoles in ready to install condition with tft lcd displays, master controller, brake controller, electrical switches, gauges, lamp indications and other required components and sub-assemblies. Modular panels are used for easy change smodifications including provisions for future additions.

Features : Ergonomically optimized layout and TFT LCD display

The system simulates the speed profile for a given trip by taking various factors into account acting on the train. The total available time for a trip is fully utilized to achieve minimum fuel consumption for complete trip. Optimal speed profiles and power (notch) level are continuously displayed to the driver as advisory input.

Railways world-over can increase throughput by running longer freight trains which require more motive power. More locomotives when bunched together cause unacceptably high coupler forces. This situation can be overcome by distributing locomotives throughout the consist of the train, which will require a means of synchronizing actions on all locomotives based on driver inputs in the lead locomotive.

Pump driven by camshaft provides high pressure fuel to all injectors. This pressure level is controlled by ECU depending upon operating speedpower. Each injector has a solenoid valve to accurately control the fuel injection start and duration. ECU controls these parameters based on operating conditions like speed, power, load, Boost Air Pressure, Coolant Temperature etc. This continuous optimization based on various operating conditions is done to reduce fuel consumption and at the same time reduce emissions. In Mechanical fuel injection system, it is not possible to independently control injection start and duration for different operating speedspowers.

Medha's BPAC system ensures that the track section is empty before permitting another train in that section, eliminates human error and controls safe movement of trains between stations. No train is permitted if there is any other train, parted train, detached wheels, rail trolley or other rail vehicle in that section.

APU is a self-contained system with its own small diesel engine coupled to low capacity compressor and alternator to maintain main reservoir pressure, charge battery, operate driver cabin HVAC system and other small loads as per customer requirement. The main engine is started only when the locomotive is actually required for movement or traction.

Current product offering has a wide selection of input power type such as ac power from auxiliary winding of traction transformer, dc power from alternators (rectified) traction converter or battery banks. Offered converters are available for range of power rating from 2.5 kva up to 300 kva with combination of ac and dc outputs for different loads.

Both Diesel and Electric locomotives use DC auxiliary power supply and small DC motor used for various applications. These DC machines are failure prone (many times leading to failure of complete locomotive) and hence need more maintenance. To increase the reliability of these motors, Medha has developed 3phase AC motor with inbuilt inverter, so that they can directly replace existing DC motors in use. These replacement motors are compatible with input DC voltage and are within the physical space constraints.