Role_of_Student_in_Nation_Building

INTRODUCTION Ferrochrome is used in the making of special types of steel, more extensively used for stainless steel is an alloy of iron and chromium. It is divided into two main types according to the carbon contents of the products i.e. High Carbon Ferrochrome (HCFC) and Low Carbon Ferrochrome (LCFC). Chromium is added as ferrochrome in various types of steel to increase hardening, wire resistance to corrosion and stability at high operating temperatures. Its corrosion resistant properties become very much marked when the chromium content exceeds 12% in low carbon steels. Since addition of other elements such as nickel, increase resistance to non oxidizing acids, improves ductility and gives cold working properties. This is essential for the production of stainless steel and cast iron. Consumption of charge chrome or HCFC has been fairly successful although the demand for LCFC is going down not only in the country but also throughout the world. The government of Orissa decided to establish IDCOL Ferrochrome and Alloys Ltd. (IFCAL) due to increasing demand of both HCFC and LCFC which was initially only imported. It is a unit of Industrial Development Corporation of India Ltd. (IDCOL) which is a state government undertaking working for the industrial development of the state. Previously ferrochrome was not produced in India, the materials were imported from foreign countries. IFCAL was the first response to the growing needs of the Indian economy. The license capacity of the plant is 10,000 M.T. LCFC and HCFC. Due to the low demand and high cost of production, production of LCFC was stopped. At present the plant produces only HCFC. Every plant involves a number of components made to work in sync with each other. All the parts like the motors, generators, fuel oil controls, lubricating oil cooling chambers, charge air tubes, compressor air chambers etc. have to respond at the correct time one after he other as per the requirement of the plant. To ensure that no failure occurs at any stage every plant has a control panel that checks and ensures the proper working of all components. At the time of malfunction of any part, either the system shuts down or the corresponding action is taken. This kind of a control system also provides for the safety of the plant and obviates any emergency or panic situation. COMPANY PROFILE IDCOL Ferrochrome and Alloys Ltd. (IFCAL, a wholly owned subsidiary of the Industrial Development Corporation of Orissa Ltd.) is a state Govt. undertaking located at Jajpur road about 5 km from the J.K. Road railway station (S.E. Rly) which is on the main Howrah-Chennai line, 340 km from Howrah and 100 mkm from the state capital Bhubaneshwar. Ferrochrome Plant was transferred as a going concern to IFCAL on 31/03/2002. Till 1969, ferrochrome in any form was not being produced in India on a regular commercial basis. The demand of ferrochrome in some main consuming countries like U.K., Japan, France etc. increased. Therefore, to meet the internal demand and to earn foreign exchange by export the Govt. of Orissa had decided to set up a ferrochrome plant at Jajpur road. The production of HCFC was startedin November, 1969 and LCFC in October, 1970. Earlier it had two furnaces; (1) Reduction furnace and (2) No slag furnace. In reduction furnace HCFC is being produced which is at present the prime product of the plant. In slag furnace LCFC was being produced. With the reduction in demand for LCFC and subsequent shutting down of its production, the plant modified the slag furnace into a reduction furnace. Generally the plant produces HCFC of around 60 MT daily, of which the former furnace yields 40 MT and the latter yields 20 MT. The main raw materials for production of HCFC are: For the production of HCFC, the following raw materials of the required quantity are used: Chromite (lumps) - 10-50 mm Chromite (friable) - 10-50 mm Chromite (briquette) - 10-50 mm The above raw materials are loaded into storage bins by conveyer belts. From the storage bins the raw materials are drawn to the screening station by means of conveyer belts again. In the screen station, coke is screened and is kept in bins as per size. Other raw materials are drawn to their respected bins from their screen station. For production of HCFC 2 reduction furnaces are used. The transfer capacities being 6.5 MVA and MVA. The employees are provided with facilities like canteen, rest sheds, dresses, liveries, safety appliances, schooling facility, hospital facilities. Strict pollution control measures are being taken by experienced engineers. Massive plantation is being done every year since the last 14 years. They have obtained an NOC (No Objection certificate) from the state Pollution Control Board. It has been accredited with ISO-9002 certificate since 8th May 1998 by Indian Registrar Quality Systems and is valid till 20/02/2006. INSTRUMENT PANEL Any power plant cannot work without a properly functioning instrument panel and a safety control panel. The former’s work is to ensure the working of the plant in case of any anomaly of any component involved in the process. It either makes that component gain its original form, speed and parameters. If this s not possible due to reasons that cannot be directly controlled by the instrument panel, the plant is made to shut down to make sure no damage is done to that component or to the ones which depend on it for proper working. This prevents the overall safety of the plant. The Instrument panel consists of a lot of electronic components which aid in the functioning and working of the plant efficiently and without any damage. This project concentrates on four of the main parts of the instrumentation panel: Exciter and rectifier assembly of brushless generator Noristachometer (main control panel) Engines speed control Servotran EXCITER AND RECTIFIER ASSEMBLY OF BRUSHLESS GENERATOR The brushless generator provides the power required to run the instrument panel after the process has once started. The initial energy is provided directly but after the process starts, it is more economical to use the energy achieved from the brushless generator. The essential feature of a brushless generator is that the functions of the exciter commutator and generator slip rings are replaced by a shaft-mounted rectifier. The machine is of the revolving field type and the exciter is a small three phase rotating armature generator directly coupled to the main generator. The rectifier assembly comprises two sets of silicon diodes, six fuses and two heat sinks. One set of diodes (comprising three or possibly six diodes) with a positive base are mounted on one heat sink and the other set of diodes with a negative base are mounted on the other heat sink. The diodes are connected in the form of a three phase bridge with one fuse in series with each arm. Diode protection units are provided in the form of surge suppressors which protect the diodes from reverse voltages induced when synchronising out of phase. They are connected across the output of the output of the rotating rectifier bridge. {draw:frame} NORIS TACHOMETER (MAIN CONTROL PANEL) {draw:frame} This is the main control for the whole of the instrument panel. It is like the supervising head of a firm. The current status of all components (channels) is displayed at this panel. It allows the operator to know which part of the mechanism is at what operating status, if it is operating at all. It also has an inbuilt mechanism to correct certain flaws if not for all. Corresponding LEDs glow for the channel if that channel is in use along with the LED that shows the next step that has been taken in response to a particular way of operation of any channel. This extremely important and indicative panel is the Noris 1000 or the Norimos 1000. During malfunction of any channel an alarm goes off indicating that an error has occurred and the corresponding programmed action is about to com into play or indicating that the system is about to undergo an shut down. Alongwith an alarm for a single channel, sometimes multiple alarms may go off, ie. those channels dependent on that channel suffer a change too and so their alarm goes of too. These alarms are places in the same alarm group. {draw:frame} POWER SUPPLY Norimos 1000 requires a battery-backed 24 V D.C. power supply. The built-in power pack provides electric isolation of the complete auxiliary power supply, including sensors and monitors. SOFTWARE FUNCTION Read-in Cycle: Each measuring channel is read in within 500 ms. Output Cycle: All outputs, alarm LEDs, output relys and the display are reset within 500 ms. The serial interface transfers an information block evey 500 ms. Thermocouple Measuring Channel: The reference junction temperature is added to the thermocouple measured value. Limit Value: The limit value can be set inside the measuring range with an accuracy of 0.5%. A maximum of 8 limit values can be connected to one sensor. It is necessary to assign one measuring channel to each limit value. It is the user’s software which decides whether monitoring is for the variable to exceed or fall below the present limit. The limit value can be changed, if the input module has been withdrawn and an adapter card inserted in between. the measuring channel involved has been selected on the display by means of the control button. The limit value is set by means of a screw driver and the setting operation can be observed on the display. If the setting conditions are not observed, the Norimos will not accept a new limit value. Alarm Delay: Each channel can be provided with an alarm delay of 0.5 to 512 seconds. The delay period is written in the user’s software. Group Alarms: Combining alarm channels to form alarm groups is affected by means of the user’s software. Alarm Inhibit: A maximum of 5 inhibit groups can be formed in a Norimos 1000. Each group can be equipped with an activation delay of 2,4 or 8 seconds. The inhibit groups are formed with an entry in the user’s software of the alarm channels. Alarm Acknowledgement: Acknowledging the visual alarm is possible only after the audible alarm has been acknowledged. The audible bridge alarm can be acknowledged separately. The general audible alarm acknowledgement includes acknowledging the audible alarm. The brightness of the bridge group alarm lamps with the dimming relay is reduced to the intensity preselected by means of the dimmer. Test: On operating the external test button, the Norimos micro-processor is branched into a test routine after every program run. The test routine will not interrupt the normal monitoring program. A channel is tested during every program run. The test program runs automatically until all channels have been tested or a disturbed channel has been detected. The run is observed on the alarm LEDs which light up during the testing of the channels. A disturbed channel is indicated visually by the alarm diode flashing. The test routing essentially consists of a comparison between the limits stored in the RAM and the potentiometer values newly read in through the test routine which are used as a reference voltage, the limit potentiometers, the data bus and the RAM memories. Self-checking Function: All auxiliary voltages required in the system are permanently monitored. The insulation checking function checks the Norimos 1000, all sensors, transmitters and the lines for earth faults. A watchdog supervises the program cycle and address control. Each alarm channel is checked during each program run whether the upeer or lower live zero limits etc. have been exceeded. This enables sensor failure, converter defects and line breaks to be detected. Serial data transmission is checked and, if an interruption exists, an alarm is initiated. (System failure). FAULT FINDING AND REPAIRS The Norimos 1000 contains software modules for fault detection. Some modles are active during normal operation, others can be brought in by operating the test button. Any defects detected by the self-checking function cause “FAULTY” to appear on the display. The instructions following this page should be followed attending to any defects. In the event of total system failure indicated by the system failure relay. {draw:frame} {draw:frame} {draw:frame} “FAULTY” Normal monitoring Mode: A monitoring channel produces an alarm and “FAULTY” appears on the selected display instead of the measured variable. The alarm system has detected an off-limit condition of the live-zero limits etc. on this monitoring channel. An input device, analog transmitter with signal card or an external signal converter should be checked. If a defect is found, the device should be replaced. If no defect can be found in the input device, the wiring to the input device should be carefully checked (retighten all terminals). Test Mode: A monitoring channel produces an alarm during the test routine, the test routine is interrupted by the alarm and “FAULTY” appears on the selected display instead of the measured variable. The test routine has detected a non-conformity between the limit stored in the RAM and the limit value newly read in by the routine. The limit stored in the RAM is the one shown on display. {draw:frame} _ _ _ _ _ _ _ _ _ _ _ _ 1. _ _ _ _ _ _ _ _ _ _ _ _ Reference voltage has changed (5 volts) : Replace mains power back. RAM memory- battery defective : Replace battery RAM memory defective : Replace RAM Data bus is interrupted or shorted : Check system bus board, connector and flat cable to add-on units. A new input module has been inserted and limit value potentiometers have not been set. The A/D converter is defective: Replace A/D converter or replace input module. _ _ _ _ _ _ _ _ _ _ _ _ _ 3. _ _ _ _ _ _ _ _ _ _ _ _ _ The correct limit value is shown on the display : The potentiometer is defective. A wrong limit value is shown on the display : The RAM memory location has been changed. Newly read in limit value cannot be read in or if the limit changes within a short period of time, then the memory location is defective and the RAM has to be replaced. EXHAUST GAS AVERAGE VALUES The Norimos 1000 may incorporate upto 4 exhaust gas average temperature monitors. (=AM) The minimum number of channel required per AM is; number of cylinders + 1, ie. The channels for the cylinder temperatures plus 1 channel for the reference junction (=VST). This minimum configuration provides monitoring of the cylinder temperatures for deviations from the average value. An additional channel is required if it desired to protect against the average temperature exceeding a minimum temperature. This channel may either be an Average Value channel or a channel for measuring point downstream of the turbine. In addition it is possible to connect an operation switch. The allocation of the channels in Noris 1000 is arbitrary. The functions of the limit potentiometer and the contents of the display partly deviate from the normal function. {draw:frame} FUNCTIONS OF INDIVIDUAL CHANNELS Cylinder Channel: Even in a healthy engine in the cylinder next to the turbine will be different from that of the cylinder further away from the turbine. This normal difference should not be included in the monitoring of the exhaust gas average value deviation. Therefore provision is made for this difference to be “corrected”. To this end, limit potentiometers are used. These permit corrections upto +/- 100 degrees. The setting is made during the commissioning of the engine at operating temperature. The potentiometer is then set so that the deviation from the average value is zero. If a cylinder channel is preselected for the display, the momentary deviation from the average value and its sign will appear instead of the limit value. Same as a normal monitoring channel, the display shows the limit value and the actual value of the average temperature. Turbine Exhaust Temperature Channel (HT): An HT channel if provided, will monitor the temperature downstream of the turbine. Strictly speaking, this channel is not part of the exhaust gas average temperature monitor; it is configured same as any channel for limit monitoring. REQUIREMENTS -The VST channel, cylinder channels, MWT and HT channel must belong to the same alarm group. -The VST group too must be the same for all channels referred to. -It is possible to use the reference junction that belongs to an exhaust gas average temperature monitor for the correction of other thermocouple channels. In this case, these channels must be assigned to the sameVST group. -It is not possible to use a VST channel for 2 exhaust gas average temperature monitors. DIGITAL SPEED CONTROL FOR ENGINES {draw:frame} The speed control used in this instrument panel is the 701digital speed control for medium-speed diesel engines in mechanical drive or generator set service. The control includes an input for a 4 to 20 mA remote speed reference setting, an internal speed reference for local control of speed, and an auxiliary voltage input for load sensor connection in load sharing applications. The 701 system for this purpose includes: A 701 digital speed control An external power source A speed sensing device An operator control A proportional actuator to position the fuel rack A terminal for adjusting control parameters An optional load sensing device It has a single printed board in a sheet-metal chassis. Connections are via two terminal strips and a 9 pin subminiature connector. The 701 control provides the following power supply input voltages, with 6watts as the nominal power consumption at rated voltage: 18-45 Vdc (24 or 32 Vdc nominal) 88-132 Vac 50/60 Hz (120 Vac nominal) 90-150 Vdc (125 Vdc nominal) The high voltage version of 88-132 Vac or 90-150Vdc is not presently available. DESCRIPTION OF OPERATION The 701 Digital Speed Control utilizes a 16-bit microprocessor for all control functions, such as computing engine speed, performing the control algorithm calculations, speed ramps, etc. All control adjustments are made with a hand-held terminal/display that communicates with the control via a serial port. The terminal/display is connected from the control when not in service to provide security against tampering. The control features a switching power supply with increased spike, ripple and EMI (electromagnetic interference) rejection. Discrete inputs are optically isolated ad capable of rejecting EMI and variable resistance in switch or relay contacts. Analog inputs are differential type with exta filtering for common mode noise rejection. This protects the control from spurious interference and noise which can speed and load shifts. The control operates automatically with two dynamic settings depending on engine speed error (speed error is the difference between the speed setting and the actual engine speed). During steady-state operation with a constant load, the control uses “slow” dynamics. This prevents the control from responding to minor fluctuations in engine speed, which eliminates potentially damaging jiggle of the actuator and fuel system. The control automatically switches to “fast” dynamics when a large speed error occurs. Operation with “slow” dynamics is restored once the control senses the return to steady-state speed. The control compensates for nonlinear fuel systems and changes in engine dynamics with load. The control dynamics are mapped as a function of actuator current, which is proportional to engine load. This provides optimal dynamics and smooth steady-state operaion for all conditions from no load to full engine load. The speed sensor contains a special tracking filter designed for low speed engines, which minimizes the effects of engine torsionals or irregularities in the gear used for sensing speed. This provides exceptionally smooth steady-state control and allows the control dynamics to be matched to the engine rather than detuned to compensate for speed torsionals. The speed signal itself is usually provided by a magnetic pickup or proximity probe supplying from 1 to 60 Vrms to the control. The 701 digital speed control provides a start fuel limiter to prevent overfueling or flooding during start-up. The limiter is set to provide the desired maximum fuel during starts. The control will reduce the fuel when the speed set point is reached as required to control engine speed, but will not exceed the start limit. The control provides a 4 to 20 mA tachometer output for an analog meter or as input to a computer. The offset and span are adjustable for range. The control also provides a 4 to 20 mA remote speed-setting input for remote setting of engine speed. The control responds to inputs from 2 to 20 mA. Inputs between 2 and 4 mA are treated as 4 mA. An input below 2 mA is considered failed and the control remains at the last reference setting (does not ramp to the 4 mA setting). The auxiliary inputs interfaces with woodward power sensors tp provide isochronous load sharing or droop operation. The power up diagnostic feature is provided to verify the proper operation of the microprocessor and memory components. The diagnostics take about seven seconds after the control is powered on. A failure of the test will turn off the output of the control. {draw:frame} SERVOTRAN {draw:frame} The servotran used in this power plant is the SIETEX SERVOTRAN. It is a potentiometric indicator/controller. IT is a rugged, compact and elegant instrument, fully transistored, working on the principle of the null balance “servo”. These instruments are used basically for measuring and controlling temperature, pressure and other process variables, using appropriate sensors which can convert these inputs to current or voltage. The servotran instruments are designed for easy accessibility inside in the case. The removal of two screws on its cover gives an access to the chassis. The two captive screws when removed from the cast aluminium frame, enables the withdrawal of the chassis from the case. The back cover can be removed by unscrewing screws located inside the external relay housing of the back bakelite cover. The component layout is arranged in such a manner that each component is easily removable for servicing. For convenience the circuitry is divided into three modules viz., the amplifier module, the control module and the power-supply bridge module. Servotran controls: fuel oil(kg/cm^2) injection cooling water (kg/m^2) {draw:frame} PRINCIPLE OF OPERATION The indicator has its input signal continuously compared via the slidewire with an e.m.f. of known value obtained from a Zener diode regulator circuit. The resulting error signal is amplified and made to drive the servo actuator to rebalance the system and indicate the new value of the input signal. Such an indication is finally reached when the error signal is very minimum, only with the compromise of any excessive gain adjustment leading to the “hunting” of the instrument. Want of sufficient adjustment can result in a dead zone which should be kept at minimum. Broken sensor upscale indication is fitted as standard in all thermocouple instruments. If the thermocouple is open, the pointer goes beyond the full scale of the instrument, leaving no ambiguity between overshooting and broken sensors. Resistance bulbs when open will also take the pointer beyond the full scale, being a conventional bridge ciruit. The voltage difference between the two contacts is amplified and fed into a Schmitt trigger circuit which in turn operates the relay. The control relay is housed on the back cover for easy accessibility without disturbing the instrument. Signal lights are incorporated to indicate the control condition. This is a two position, on/off controller with a control sensitivity fixed at better than 0.3% and can be used for switching on and off the heater, solenoid valve etc. this can also be used for high/low alarm. LOCATION OF THE INSTRUMENT These instruments are to be located in a place where the ambient temperatures are reasonably stable. Adequate lighting should be provided in places where the lighting is poor. ELECRICAL SUPPLY Servotran instruments are designed for a power supply of 220/240V 50C/s. A voltage selector link is provided at the back cover so that the use choose 220V range or 240V range. Each range will take care of fluctuations in supply voltage by +10%. The instruments when dispatched, from the factory are linked to the 240V range, unless otherwise specially mentioned in the order. Otherwise for lower voltage ranges the link should be connected suitably. THERMOCOUPLE INSTRUMENTS Correct compensating cables are to be used while connecting the thermocouple terminals with the instrument terminals. The correct “polarity” connections must be ensured as otherwise the instrument is sure to show wrong readings. Terminals numbered 1 is positive. CONNECTION DIAGRAMS Circuit diagrams given here are: Two controllers Three position controllers Representative wiring diagrams for functions stated are given and for any other specific applications circuit diagrams can be obtained from us. When these connections are made as per the circuit diagrams the controller operation can be checked up as follows: {draw:frame} The polarity of the mains supply terminals are to be checked. The voltage settings made in the link are to be checked. Proper connections of the compensating cables are made. Power is supplied to the instrument. The thermocouple connections are then broken and movement of the indicating pointer is watched. This moves upwards and go beyond the full scale. During this process as the indicating pointer passes through the control pointer (red) the corresponding lamp is then cut off. The thermocouple is connected again, the instrument will read the temperature of the hot junction of the thermocouple. When the control arm is moved over the scale, the indicating lamp action will operate when this passes through the indicating pointer. Now the control pointer should be set, bringing the knob provided for the same to the required value. Then the control circuit is connected. TROUBLESHOOTING CONCLUSION Instrument panels, find application in diverse industries for multiple purposes. These panels are perfect to meet diverse technical requirements under stringent and varying site conditions, and utilize floor space more efficiently. Instrument panels are used in different industries for providing protection from short circuits and overloads. Use of modern technology imparts these panels distinguished features and makes them highly popular. BIBLIOGRAPHY For the completion of this project work, the following books and websites have been referred to: Manual for Noris 1000 Manual for Woodward speed control Manual for Servotran Google search www.ifcalorissa.com