MEC628V2 Questions - 4 PDF

1)Parts of DC Motor - commutator - brushes - Bearing inside - Gear 2)Disadvantages of DC Traction Motor - Have commutator and brushes - More Maintenance - very bulky in size Occupies more space in the bogie - Power regeneration facility is not available in DC motor fitted lo...

1)Parts of DC Motor - commutator - brushes - Bearing inside - Gear 2)Disadvantages of DC Traction Motor - Have commutator and brushes - More Maintenance - very bulky in size Occupies more space in the bogie - Power regeneration facility is not available in DC motor fitted loco - Need to be used a separate converter for regeneration 3)Advantage of AC Traction Motor - No commutator and brushes - Less Maintenance - Small in size Occupies less space in the bogie - Power regeneration facility is available in AC motor fitted loco 4\) CLW has been manufacturing 3 phase electric locomotives whose technology was acquired through ABB/ADTRANZ 5)3ph IGBT base locomotive's converters are based on **GTO** Technology. 6)Draw the symbol of IGBT 7)Draw the symbol of GTO and IGBT 8\) Which one is the most advanced power device in power electronics among the following? - IGBT - GTO - SCR - BJT 9Which is the first Indian company to design and develop indigenously the IGBT-based 3-phase drive propulsion equipment, type MEC628V2, for WAG9/WAG9H/WAP7/WAP5 electric locomotives? - ABB SEIMENS - MEDHA SERVO DRIVES(P)Ltd - CGL 10\) IGBT-based 3-phase drive propulsion equipment is commonly used in - WAG9 - WAG9H - WAP7 - WAP5 ALL 11\) What type of AC motor is used in the WAG-9 locomotive? - 6 FRA 6068 (WAG9/WAP7) - 6FXA 7059 (WAP5) 12)What is 1Hr motor rating which is used in the WAG-9 locomotive? - 1156 HP, 2089 V, 290A, 1135 rpm (WAG9/WAP7) - 1563 HP, 2044 V, 396A, 1485 rpm (WAP5) 13)What is Cont. Rating motor rating which is used in the WAG-5 locomotive? - Cont. Rating : 1156 HP (850 kW), 2180V, 270A,1283 rpm,132Hz (WAG9/WAP7) - 1563 HP (1150 kW), 2180V, 370A,1585rpm,160.3Hz (WAP5). 14)What is winding (P,V,I)and total rating of transformer 1 Primary winding & 8 Secondary windings 4 Traction windings (4x 1449 kVA) 1 Auxiliary winding (334 kVA) 1 Filter winding (400 kVA) 2 Hotel load windings (2x 622.5 kVA) Total power rating= 7775 kV 15)What are objectives of IGBT based 3-phase drive propulsion equipment for Electric loco's - Indigenous development-so as to provide quick response in case of problems, improvements and upgrades - To provide an integrated system to avoid compatibility and interface issues - To provide high level of redundancy (VCU, Traction converter and Auxiliary converter) - To provide a flexible system with user settable parameters for easy changes by Indian Railways 16)Draw the Block diagram and explain the function of VCU - MEC628 is provided with two Vehicle Control Units (VCU1 & VCU2) located under SB1 & SB2 cubicles Each VCU is provided with a CPU card - The CPU inside the master VCU controls the complete system operation based on the signals measured, commands received from the loco pilot, monitoring conditions of various equipment etc It is a Mother Board based design with proper polarization of connectors on plug-in type modules to prevent accidental insertion into wrong position 17)Explain the function of MDOPCAN & MDIPCAN cards - Provided with a 16-bit microcontroller, which gets the digital output channel data from MVCUCC on main CAN communication channel and from MACC on Redundant CAN communication channel (only in case of failure of main channel), whenever commanded - Each digital output module has provision for 20 channels. - This card consists of a 16-bit micro controller, which reads all the digital input channels periodically and transmits the information ü to MVCUCC on Main CAN communication channel and to M628ACC on Redundant CAN communication channel, whenever requested. Each digital input module has provision for 24 channels. 18)What is The MVCUCC, and what control activities does it perform in the locomotive? - It is the central processing unit of the entire computer system - It contains a 32-bit micro controller, various peripherals and interface circuits such as CAN, RS485, RAM, etc - This module works on ±15 V and ±7.5 V DC input voltages - If VCU1 Main CPU fails, the locomotive control operation changes over to VCU2 Main CPU - Continuously communicates with on board sub-systems like Traction Converter, Aux Converters etc - Pantograph Control - 2\. VCB Control - 3\. Compressor Control - 4\. Reference Ventilation Level Computation - 5\. Wheel Diameter Calibration - 6\. Wheel Slip Control - 7\. Drive Meters - 8\. Multiple Unit Communication - 9\. Test modes through DDU 18)Draw the Block diagram of VCU and explain functions of VCU? 1.Control Stand Integration 2\. Brake System Integration 3\. Traction Converter Interface 4\. Auxiliary Converter Interface 5\. Driver Display Unit Interface 6\. Event Recording & Energy Monitoring 7\. User Settable Parameters 8\. Fault storing & Downloading 19\) Explain Control Stand Integration - Each VCU is integrated with the control stand (cab) that is closest in terms of physical distance - Both VCUs in turn share control stand information with each other (VCU redundancy) - Integration with control stand includes interface with, - Master controller (Reverser handle, TE/BE Throttle handle) - Drive meters like TE/BE meter for each bogie - Push button / toggle switches like BPCS, BPPB, BPVR, Spring loaded switches like ZPT, BLDJ, TE Limit switch etc. - Indication Lamp 20\) Explain Brake System Integration - Existing interface with brake system has been retained - VCU interface with E-70/CCB Brake system through Digital and Analog I/Os - Limited Blended braking as is available with the existing control electronics - When loco runs in the regeneration mode, and if regeneration is failed, VCU commands brake system to apply equivalent pneumatic brake through analog output. 21)Explain Traction Converter Interface? - Redundant CAN interfaces through separate processors of each VCU - Motoring/Braking Torque command based on Throttle - Traction Converter faults & status feedback - Traction Converter Faults & fault data packs downloading through VCU - Traction Converter configuration (user-settable parameters) on power up by VCU - Functions achieved through integration of VCU & LTC - Wheel slip control - Wheel diameter calibration. 22)Explain Auxiliary Converter Interface? - Redundant CAN interfaces through separate processors of each VCU - Auxiliary Converters commands from VCU, faults & status feedback back to VCU - Auxiliary Converter Faults and fault data packs downloading through VCU - Auxiliary Converter configuration (user-settable parameters) on power up by VCU - Auxiliary Converters failure change-over controlled by VCU 23)Explain Redundancy in VCU Module Failed Redundant option --- -------------------------------------------------- ---------------------------------------------------------------------------------------------- 1 Main Control Computer (MVCUCC1) in VCU1 1 VCU2 will take over the control function, interfaces with other system operation & display 2 Auxiliary Communication Computer (MACC1) in VCU1 No effect. MVCUCC1 (same VCU) will already having communication with subsystems 3 3 Any Digital Input/Output module of either VCU No effect, as important inputs/outputs are duplicated in two cards. 4 Physical CAN OFC cable Redundant CAN through MACC will do the communication 5 MAIP module / (Throttle position) TE/BE demand by Aux Contact inputs (0%, 33%, 66%, 100% contacts in Throttle controller) 6 MAOP module/ (TE/BE meters) Seen on Driver display 24)Explain Function of LCD TFT Based Driver Diplay - It communicates with the VCU system through RS 485 link - It displays the data sent by VCU system in graphical as well as in text format - MDS740 has its own power supply module for generating regulated power supplies required for display electronics - These regulated power supplies are generated from nominal 110 V DC input power from the locomotive battery. - Main Menu, Loco status , Entire Archive Faults, Inching mode , Self test, Meter test, Blower test, 25)Draw the LTC Circuit Block Diagram. 26)Explain the function of Line and Traction Control Unit(LTCU) - LTCU consists of 2- Line Converter computers (LIC) 3 - Traction Inverter Control Computers (TIC) Main function of LIC - Unity Power Factor at AC input and minimum Harmonics ,Stable DC Link Voltage - Main function of TIC - Independent Motor Torque control (Motoring / Braking) ,Wheel slip control - Both LIC and TIC do fault diagnostics based on voltage, current, speed, temperature, pressure sensors - LIC and TIC communicate with VCUs through redundant CAN - LIC and TIC communicates among themselves through dedicated CAN communication. 27\) Explain the function of Line Converter Control Computer (MLICCV2) - MLICCV2 consists of a 32-bit Digital Signal Processor (DSP) and one16-bit Microcontroller - Both communicate with each other to share the control, status and protection information - DSP measures the input and output voltage and currents and performs the control and protection activities of Line Converter - Microcontroller performs all the auxiliary functions. 28\) Explain the function of MLTCPSV2 - MLTCPSV2 card provides various regulated power supplies required for the modules of LIC - These regulated power supplies are generated from nominal 110 V DC input power from the battery 29\) what are types of Analog Inputs in Line Converter. Analog inputs: Hotel load current signal DC link voltage signal Rectifier heat sink temperature signal. T/F oil temperature signal Line converter Input current signal Primary voltage PT signal Common analog inputs: Auxiliary current signal LTC coolant pressure signal Earth fault voltage signal Transformer oil pressure signal Harmonic filter current signal Primary current signal Brake chopper current signa 30\) what are the Digital Input Output in Line Converter Digital Inputs: 1\. Precharging Contactor Feedback 2\. Line SW Close RLY FB 3\. Line SW Open RLY FB 4\. Line SW Close State FB 5\. Line SW Open State FB 6\. Filter Contactor Feedback 7\. Filter Adaption Contactor Feedback 8\. Filter Discharging Adaption Contactor Feedback 9\. ADB PS Health 10.Earthing Switch Feedback Digital Outputs: 1\. Precharging Contactor output 2\. Line SW Close RLY output 3\. Line SW Open RLY output 4\. Filter Contactor output 5\. Filter Adaption Contactor Output 6\. Filter Discharging Adaption Contactor Output 31)Explain the function of Traction Inverter Control Computer (MTICCV2) - MTICCV2 consists of a 32-bit Digital Signal Processor (DSP) and one 16-bit Microcontroller - Both communicate with each other to share the control, status and protection information - DSP measures the input and output voltage and currents and performs the control and protection activities of Line Converter. - Microcontroller performs all the auxiliary functions 32)What are the Traction Inverter Analog Inputs Analog Inputs: 1\. DC Link Voltage Sensor 2\. UV Phase module Heat sink Temperature Sensor 3\. W Phase module Heat sink Temperature Sensor 4\. TM stator Temperature Sensor1 5\. TM stator Temperature Sensor2 6\. TM U phase current sensor 7\. TM W phase current sensor. 33)Explain the function of MLTOFCV2 card - MLTOFCV2 module consists of CAN communication interface circuit which converts the electrical signals to optical light for data transmission and from optical light signal to electrical signal for data receiving - MLTOFC also consists of Over Voltage Limiting driving circuit (driven from both LICs) and six DIP channels (all the control 5 V circuit to external 110 V). 34)How many **6** INVPS cards in one LTC 35)Explain the function of Line and Pre-charge Contactor The input switch gear section consists of Main (line) contactor Pre-charge contactor and pre-charge resistor - The main and pre-charge contactors are used to isolate or to connect the main transformer to traction converter unit. - The pre-charge resistor and pre-charge contactor together are called as pre-charge circuit - The pre-charge resistor is switched in series with input to the line converter by pre- charge contactor. - The pre-charge resistance is used to limit the current through the DC Link capacitors and IGBTs (diodes) 36)Explain the function Over Voltage Limiting Circuit in LTC - Over voltage protection circuit comprises over voltage limiting IGBT Module and over voltage limiting resistor (4 to 6 ohms) - The over voltage limiting circuit is used to limit the over-voltages in DC Link capacitors during abnormal conditions or during transients - Over voltages in the DC Link capacitors may occur due to Non-receptive OHE during regeneration Transient Load Condition 37)Explain the function Earth Fault Detection circuit and how it works. There are two sets of resistor branches connected in series (their equivalent resistances are R1 and R2) between DC link terminals. R1 and R2 are different resistances each of values 66 kΩ and 20.4 kΩ respectively 1. Ue/Udc =0.5 for 2sec \-\--Earth fault on +Ve side 2. 0.5 \< (Ue/Udc) \ - IGBT open circuit failure - Reduction of 1/6th locomotive power - Gate Drive card - Reduction of 1/6th locomotive power - Gate Drive Power Supply - Reduction of 1/6th locomotive power - Short Circuit of IGBTs - Reduction of half of locomotive power - Speed Sensor - No reduction in locomotive power, if at least one quadrature signal is available - Temperature Sensor - No reduction in locomotive power (Two temperature sensors are available in the TM) - OVL IGBT module - No reduction in locomotive power, if IGBT fails in open condition. 42\) What is Coolant Maintenance, and how is it performed? - System should be thoroughly checked for corrosion, scale & sedimentation - Colour & pH of the coolant to be monitored quarterly - Coolant normally to be changed after every 5 years - Accepted pH ranges: 7.7 to 8.3 (during filling) & 7.1 to 8.9 (while in service) 43)Draw the Block Diagram of ACU1 & ACU2 including transformer winding. 44)Briefly explain the Electric locomotive Aux. Converter section. - WAG9/WAG9H/WAP7/WAP5 Electric locomotive is provided with three Auxiliary converters of 132 kVA rating each - Physically in one locomotive, two aux converter cubicles are available, which are called ACU1 and ACU2 - ACU1 consists of 1no. of 132 kVA converter, which is called AC1 - ACU2 consists of 2nos. of 132 kVA converters. The cubicle contains AC2, AC3 and one Battery Charger Each 132 kVA Auxiliary converter consists of one Line Rectifier, DC Link and one Inverter - Battery charger is available in ACU2 cabinet, can be driven by either of the AC2 or AC3 converters in that cabinet - The three phase output of ACs is nominal 415 V and that of the battery charger is 111V. 45)what are Sub-assemblies in Aux. Converter Auxiliary Converter components Line Rectifier DC Link Inverter Battery Charger (only in Auxiliary Converter 2 & 3) Three phase output of the each Aux Converter is 415 V and that of the battery charger is 111 V Thyristors as active switch in Line Rectifier and IGBTs for Inverter and battery charger The existing locomotive cooling system has been retained. Input Fuse \-\--550 A, 1300 V MOV \-\-\--2 x 750 V, 80 k Ohms DC Link Capacitor \-\-\--3 x 2.9 mF OVLR \-\--4 Ohms SFC \-\--3 x 37.5 micro F, 850 V AC, 3x 56 A Bleeder Resistor \-\-\--5 x 15 k Ohms CT\-\-- 1000 A/ 1 A SFI \-\-\--124 micro H, 185 A DC- DC Transformer\-\-- 13 kVA, 550 V/ 220V Input Voltage Sensor \-\--2000 V/ 50mA Snubber Capacitor \-\-\--0.68 micro F, 1000 V Battery Charger 3-phase rectifier diode \-\-\--1600 V,150 A HFDCDC IGBT \-\--1200 V, 200 A Battery Charger Output Rectifier Diode \-\-\--600 V, 304 A DC O/P Fuse\-\-\-- 200 A, 700 V Output Change-over Contactors (52/1, 52/2, 52/3)\-\-- 1000 V AC, 265 A HFDCDC IGBT Snubber Capacitor \-\-\--0.68 micro F,1000 V Battery Charger O/P CT \-\--200 A/ 100 Ma 46\) Explain Function of Control Card (M304V2CC) - One 16-bit Micro Controller running at 80 MHz or higher clock. It communicates with power modules through through CAN. - Microcontroller Communicates the same information of the power modules through CAN communication Analog Inputs: 1\. I/P ELD CHANNEL 2\. 3-PH EARTH LEAK CURRENT F.B 3\. TEMPERATURE CHANNEL (AUX Internal Ambient) 4\. LOCO BATTERY VOLTAGE. 47)What are the Digital Input and Outputs M304V2DIO card Digital Inputs: 1\. CANTACTOR 52/3 & 52/4 FEEDBACK 2\. BATTERY CHARGER\_MCCB\_FEEDBACK 3\. CONTACTOR 52/1 & 52/5 FEEDBACK 4\. CONTACTOR 52/2 FEEDBACK 5\. AUX-CONTACTOR 52.4/1 & 52.5/2 FEEDBACK 6\. AUX-CONTACTOR 52.4/2 & 52.5/1 FEEDBACK 7\. INPUT FUSE FB Digital Outputs: 1\. 52/1 ENABLE SIGNAL TO 52.3/1 2\. 52/2 ENABLE SIGNAL TO 52.3/2 3\. 52/3 ENABLE SIGNAL TO 52.3/3 4\. 52/4 ENABLE SIGNAL 48)Explain the function of Power Supply Module in Aux.Converter. - Power Supply module supplies various DC-DC regulated power supplies required for all the modules inside the Auxiliary Computer - These regulated power supplies are generated from nominal on-board power 110 V DC input. 49)Explain the function Line rectifier and & DC Link in Aux. converter - Line Rectifier is the interface between the Traction Transformer auxiliary winding and the DC Link. Line Rectifier Components Fuse Surge suppressors LC filter Semi Controlled Thyristor rectifier - Converts AC input from Transformer to DC and stores in DC link capacitors bank - The DC Link circuit consists of an LC filter (existing inductor in Transformer tank will be re-used) - The function of brake chopper is to reduce the over voltages on DC link. 50)Explain the function of Inverter in Aux.converter - Interface between the DC Link and the three phase output to the Auxiliary loads - VVVF output with three frequencies (37, 47, 50Hz) - Inverter Components IGBT\'s Snubber capacitors - Sine filter - to reduce voltage & current harmonics - Basic control parameters - voltage and fundamental frequency of the output voltage. - Sensors provided Current sensors Voltage sensors 51)Draw the block diagram and Explain the function of Battery charger Module in Aux. converter It converts the 415V AC from Aux. converter into 570V DC. 570V DC is converted into 111V DC. Battery charger module consists of individual DSP for controlling and monitoring purpose. AIP in Battery charger module 1\. BATTERY CHARGER DC LINK VOLTAGE F.B 2\. TRANSFORMER PRIMARY CURRENT F.B 3\. DC-DC CONVERTER O/P CURRENT F.B 4\. DC-DC CONVERTER OP VOLTAGE F.B 5\. BATTERY CURRENT F.B 6. TEMPERATURE CHANNEL (DCDC IGBT HS). Battery Charger consist of - Three Phase Bridge Rectifier High Freq. DC-DC converter Uncontrolled Rectifier LC Filter Capable of charging NiCd battery with 30 A rating (110 A limiting current rating) - Redundant control from either AC2 or AC3 computers Sensors provided Voltage sensors, Current sensors 52)What are the protections in Aux. converter 1\. Fuse failure in converter 2\. Input over voltage / under voltage 3\. Input over current 4\. Ground fault in AC input circuit 5\. Over and Under voltage protection in DC link 6\. DC Link over current 7\. 3 phase Output overload 8\. Output short circuit 3 phase terminals 9\. Ground fault in 3-phase loadoutput 10\. Auxiliary converter phase fault 11\. Thermal overloading 12\. Battery charger Input MCCB trip 53)Explain the redundancy in Aux. converter? Load distribution among the Auxiliary Converters Automatic switching of load from one Auxiliary Converter to another in case of failure of any of the Auxiliary Converters Battery Charger can be driven either from AC2 or AC3 and controlled by either of their computers (using independent sensors) There are four operating cases when AC\'s fail Normal operation When AC-1 is isolated When AC-2 is isolated When AC-3 is isolate 54)Draw the Load change over configuration When AC-1 is Isolated. 55\) Draw the Load change over configuration When AC-2 is Isolated. 56\) Draw the Load change over configuration When AC-3 is Isolated. 57 Auxiliary Converter Cubicle-1 Main 58)What is the full form of AOH **Annual Overhaul** 59)What are tasks to performed during maintenance. Overall the unit is maintenance-free. During AOH following checks are to be carried out- 1\. Blowout dust from entire unit. 2.Check input & output cable connections. 3.Open the unit & ensure the connections of all assemblies. 4.Check for wear & tear of bolts. 5.ACU1\-\--Check exit air velocity at four places in exit duct & average velocity should be more than 7.0 m/s. 6.ACU2\-\-- Check exit air velocity at four places in exit duct & average velocity should be more than 5.0 m/s (for AC2) & 6.0 m/s (for AC3) 7.If observed air velocity is less than specified, then the machine room air suction filter should be cleaned as per standard practice followed in Railway Loco Shed 60\) What are the conditions and protections for VCB opening? - Transformer Primary return current is \ 800 A rms for 50 msec after Switch ON the VCB then VCB will Open - Maximum Current Relay 78 is ON then VCB will Open - Transformer Primary return current is \> 330 A rms for 50 msec duration during normal operation then VCB will Open - When Harmonic Filter current is \> 600 A within one second after switch ON of Harmonic filter then Filter Contactor Open & VCB Open - When Harmonic Filter current is \> 410 A during normal operation then Filter Contactor Open & VCB Open - When Auxiliary converter current is \> 400 A then VCB Open - Converter Coolant Temperature is \> 80°C for continuous 10 seconds then VCB Open