Final Training Report (Turbocharger)

SUBMITTED BY:-OSCAR ARUN LOUISB.Tech. ME

LOCO SHED TRAINING REPORT

ACKNOWLEDGEMENT

I take this opportunity to express my sincere gratitude to all the people who have been associated in the successful completion of industrial training and this project. I would like to show my greatest appreciation to the highly esteemed and devoted technical staff, supervisors of the Diesel Loco Shed, Agra. I m highly indebted to them for their tremendous support and help during the completion of our training and project.

I m grateful to the D.M.E, Loco Shed and training co-ordinator Mr. Pratap for admitting me in the shed for my industrial training. I would like to thank to all those peoples who directly or indirectly helped and guided me to complete my training and project in the shed.

I would also like to express my heartfelt gratitude to the Dean of “Shepherd School of Engineering and Technology” and Head of the Department of “Mechanical Engineering and Applied Mechanics” for providing me an opportunity to go for the industrial training.

Finally, I may say that I do not claim absolute perfection . However, I have strived hard to gain knowledge during the training and present a good project report.

OSCAR LOUIS

B.Tech ME (VIIth)

S.H.I.A.T.S

INDIAN RAILWAY HISTORY

Indian Railways is the state-owned railway company of India. It comes under the Ministry of Railways. Indian Railways has one of the largest and busiest rail networks in the world, transporting over 18 million passengers and more than 2 million tonnes of freight daily. Its revenue is Rs.107.66 billion. It is the world's largest commercial employer, with more than 1.4 million employees. It operates rail transport on 6,909 stations over a total route length of more than 63,327 kilometers(39,350 miles).The fleet of Indian railway includes over 200,000 (freight) wagons, 50,000 coaches and 8,000 locomotives. It also owns locomotive and coach production facilities. It was founded in 1853 under the East India Company.

Indian Railways is administered by the Railway Board. Indian Railways is divided into 16 zones. Each zone railway is made up of a certain number of divisions. There are a total of sixty-seven divisions. It also operates the Kolkata metro. There are six manufacturing plants of the Indian Railways. The total length of track used by Indian Railways is about 108,805 km (67,608 mi) while the total route length of the network is 63,465 km (39,435 mi). About 40% of the total track kilometer is electrified & almost all electrified sections use 25,000 V AC. Indian railways uses four rail track gauges:-

1. The broad gauge (1670 mm)2. The meter gauge (1000 mm)3. Narrow gauge (762 mm)4. Narrow gauge (610 mm).

Indian Railways operates about 9,000 passenger trains and transports 18 million passengers daily .Indian Railways makes 70% of its revenues and most of its profits from the freight sector, and uses these profits to cross-subsidies the loss-making passenger sector. The Rajdhani Express and Shatabdi Express are the fastest trains of India

CLASSIFICATION

1. Standard “Gauge” designations and dimensions:- W = Broad gauge (1.67 m) Y = Medium gauge ( 1 m) Z = Narrow gauge ( 0.762 m) N = Narrow gauge ( 0.610 m)

2. “ Type of Traction” designations:- D = Diesel-electric traction C = DC traction A = AC traction CA=Dual power AC/DC traction

3. The “ type of load” or “Service” designations:- M= Mixed service P = Passenger G= Goods S = Shunting

4. “ Horse power ” designations from June 2002 (except WDP-1 & WDM-2 LOCOS)

‘ 3 ’ For 3000 horsepower ‘ 4 ’ For 4000 horsepower ‘ 5 ’ For 5000 horsepower ‘ A ’ For extra 100 horsepower ‘B’ For extra 200 horsepower and so on.

Hence ‘WDM-3A’ indicates a broad gauge loco with diesel-electric traction. It is for mixed services and has 3100 horsepower.

DIESEL SHED AGRA

INTRODUCTION

Diesel locomotive shed is an industrial-technical setup, where repair and maintenance works of diesel locomotives is carried out, so as to keep the loco working properly. It contributes to increase the operational life of diesel locomotives and tries to minimize the line failures. The technical manpower of a shed also increases the efficiency of the loco and remedies the failures of loco.

The shed consists of the infrastructure to berth, dismantle, repair and test the loco and subsystems. The shed working is heavily based on the manual methods of doing the maintenance job and very less automation processes are used in sheds, especially in India.

The diesel shed usually has:-

Berths and platforms for loco maintenance. Pits for under frame maintenance Heavy lift cranes and lifting jacks Fuel storage and lube oil storage, water treatment plant and testing

labs etc. Sub-assembly overhauling and repairing sections

ABOUT DIESEL SHED AGC

Diesel Shed, Agra started functioning in 1986. The shed is headed by DME (D) was AGC. It is located at km. 1334/5 about 1.25 Km away from AGC station towards Delhi end. A captive store headed by AMM (D) is attached to the shed. At present the shed holds WDS4 and WDM2 both with Dual Break System, especially for the shunting purpose. The shed cater the needs of Northern Central Railway.

No doubt the reliability, safety through preventive and predictive maintenance is high priority of the shed. To meet out the quality standard shed has taken various steps and obtaining of the ISO-9001-200O& ISO 14001 OHSAS CERTIFICATION is among of them. The Diesel Shed is equipped with modern machines and plant required for Maintenance of Diesel Locomotives and has an attached store depot. The morale of supervisors and staff of the shed is very high and whole shed works like a well-knit team.

Introduction to WDM-2

WDM-2s are 2600 hp Alco models (RSD29 / DL560C). Co-Co, 16-cylinder, 4-stroke turbo-supercharged engine. Introduced in 1962. The first units were imported fully built from Alco. After DLW was set up, 12 of these were produced from kits imported from Alco (order no. D3389). After 1964, DLW produced this loco in vast numbers in lots of different configurations. This loco model was IR's workhorse for the second half of the 20th century, and perhaps the one loco that has an iconic association with IR for many people. These locos are found all over India hauling goods and passenger trains — the standard workhorse of IR. Many crack trains of IR used to be double-headed by WDM-2 locos; this has decreased now owing to the electrification of most important sections and the use of more powerful locos. A single WDM-2 can generally haul around 9 passenger coaches; twin WDM-2's were therefore used for 18-coach trains.

Jumbos – A few locos of the WDM-2 class produced in 1978-79 have a full-width short hood; these are unofficially termed 'Jumbos' by the crew. These range from serial numbers around 17796 or so to about 17895 or so (17899 and above are known to be 'normal' WDM-2s). These were apparently produced with the idea of improving the visibility for the drivers, but it was learned later that it did not make much of a difference under the typical operating conditions of these locos. Some of these were later modified to have narrower short hoods to look more like the other WDM-2's. Two locos, #17881 and #17882, were trial locos produced by DLW when they were considering shutting down Jumbo production; these look like ordinary WDM-2 locos, even though there are other Jumbos with higher road numbers than them. Some Jumbos have undergone further modifications: Loco #17854 was a Jumbo based at Jhansi in 1981; now [6/04] it has been rebuilt as a WDM-3A locomotive (based at Pune) by DCW, Patiala.

The classification WDM-2A is applied to those that were re-fitted with air brakes (most of these therefore have dual braking capability), while WDM-2B is applied to more recent locos built with air brakes as the original equipment (these very rarely have vacuum braking capability in addition, especially if they have been rebuilt by Golden Rock). (However, in the past, before the widespread use of air-brakes, a few modified versions with a low short hood at one end like the WDS-6 were

also classified WDM-2A.) A few WDM-2 locos of the Erode shed have been modified and sport a full-forward cab at one end, with the dynamic brake grid, blower, etc. moved between the cab and the traction alternator.

The original Alco designs had a 10-day, 3000km maintenance schedule, which was later extended by some modifications to a 14-day schedule. Now [1/02], the schedule is being extended to 30 days by increasing the capacities for various fluids (lubrication oil, etc.), and improving some bearings (mainly, using roller bearings for the suspension). The original WDM-2 bearings were very susceptible to failure. However, given the age of this model, unsurprisingly even locos that have been modified for a 14-day schedule do often require more frequent maintenance or minor repair so they end up being put on a 7-day schedule anyway.

WDM-2 locos are excepted from the new mainline diesel classification scheme and will remain classified as WDM-2 and not 'WDM-2F' as they might be in the new scheme based on their horsepower.

The first one supplied by Alco was #18040. This one is no longer in use and is now preserved at the National Railway Museum at New Delhi. The second one from Alco, #18041, is currently [7/05] homed at Kalyan shed and is often seen hauling the Diva - Vasai DMU service. The first WDM-2 built by DLW, #18233, is now at Andal shed (not much in use). The last WDM-2's were in the 16000 series. The very last one is #16887.

The WDM-2 locos have a max. speed of 120km/h. There are generally speaking no restrictions for running with the long hood leading, although it's been reported that in some cases the practice was to limit it to 100km/h. The gear ratio is 65:18.

Some WDM-2 units are being converted [2/02] to have AC-DC transmission (alternator driving DC traction motors) by DCW, Patiala. Golden Rock workshops have also been renovating some WDM-2 locos with new features such as twin-beam headlamps.

Only one WDM-2 loco (#16859, Ernakulam shed) is known to have had cab air-conditioning fitted. This was the first loco to have air-conditioning in India; this was done by the ERS shed in 1997 right after receiving the loco from DLW, but it was disabled later as the auxiliary alternator proved too weak to run the air-conditioner well.

A few WDM-2 locos downgraded for shunting duties have been seen marked with a WDM-2S class name; e.g., some at Itwari shed [2003] and some at Kurla. A few have also been spotted bearing the class name WDS-2, e.g., those

at the Kalyan shed where they are used for shunting. These appear to be quirks of the local shed staff and not officially recognized classifications.

DCW Patiala has rebuilt some WDM-2 units to class WDM-3A/WDM-2C specifications. These are a little different from the normal WDM-2C from DLW. They look very similar to WDM-2's, except for a bulge on one of the doors of the hood; this is due to the presence of a centrifugal fuel filter which moved there because the model required larger aftercoolers. There are some other slight differences in appearance. These units have a GE turbocharger and a different expressor with integral air drying facility. They have a Woodwards governor which leads to even running and idling, and (to the great disappintment of Alco smoke fans) reduces the amount of black smoke during intense acceleration. These also have roller bearings for the suspension, improving on the longstanding problem of bearing failures on the regular WDM-2 model.

TURBO SUPERCHARGER

INTRODUCTION

The diesel engine produces mechanical energy by converting heat energy derived from burning of fuel inside the cylinder. For efficient burning of fuel, availability of sufficient air in proper ratio is a prerequisite.

In a naturally aspirated engine, during the suction stroke, air is being sucked into the cylinder from the atmosphere. The volume of air thus drawn into the cylinder through restricted inlet valve passage, within a limited time would also be limited and at a pressure slightly less than the atmosphere. The availability of less quantity of air of low density inside the cylinder would limit the scope of burning of fuel. Hence mechanical power produced in the cylinder is also limited.

An improvement in the naturally aspirated engines is the super-charged or pressure charged engines. During the suction stroke, pressurised stroke of high density is being charged into the cylinder through the open suction valve. Air of higher density containing more oxygen will make it possible to inject more fuel into the same size of cylinders and produce more power, by effectively burning it.

TURBOSUPERCHARGERS

A turbosupercharger, or turbo, is a gas compressor that is used for forced-induction of an internal combustion engine. It increases the density of air entering the engine to create more power.

A turbosupercharger has the compressor powered by a turbine, driven by the engine's own exhaust gases. The turbine and compressor are mounted on a shared shaft. The turbine converts exhaust heat and pressure to rotational force, which is in turn used to drive the compressor. The compressor draws in ambient air and pumps it in to the intake manifold at increased pressure, resulting in a greater mass of air entering the cylinders on each intake stroke.

Turbosupercharging dramatically improves the engine's specific power, power-to-weight ratio and performance characteristics which are normally poor in non-turbosupercharged diesel engines.

TURBOS USED IN DIESEL LOCOMOTIVE

In diesel locomotives, different turbos are used for different engines on the basis of their horsepower and make. Still, their general function remains the same i.e.

to provide compressed air to the engine by employing the energy of exhaust gases. The exhaust manifold is connected to the inlet of the turbocharger. The exhaust gases enter the gas inlet casing where they are directed towards the nozzle ring. The function of the nozzle ring is to guide the exhaust gases and reduce shock on the turbine blades. The exhaust gases impinge on the turbine blades and cause the turbine to rotate on their way out to the atmosphere

through the chimney.

The rotating turbine causes the impeller of the compressor to rotate along with it since they are mounted on the same shaft. The compressor starts sucking air through the air inlet casing and compresses it due to the centrifugal action of the impeller. After leaving the impeller, the air gets compressed further in the diffuser vanes. From here the compressed air is passed into the blower casing, which guides the air to an after cooler.

The function of the after cooler is to cool the compressed air and consequently reduce its specific volume. The pressure of this compressed air is in the range of 1.2-1.8 kg/cm2, and this is known as BOOSTER AIR PRESSURE (BAP). This compressed air is then introduced into the air gallery, which is connected to the intake valves of all the cylinders.

ALCO FRONT VIEW

ALCO TOP VIEW

ALCO ASSEMBLY

GE (DOUBLE DISCHARGE) FRONT VIEW

GE (DOUBLE DISCHARGE) TOP VIEW

GE (DOUBLE DISCHARGE) BOTTOM VIEW

GE (DOUBLE DISCHARGE) ASSEMBLY

TURBO OPERATING DIFFICULTIES:

Operating difficulties can be prevented providing the daily turbocharger operating data is measured and regular maintenance and inspection routines are adhered to.

To assist in identifying causes of performance deterioration, the following table has been formed:

OPERATING DIFFICULTIES

PROBABLE CAUSE REMEDIAL MEASURES

Engine starts running but the turbocharger does not.

Foreign matter/debris caught between the turbine blade tips and the shroud ring.Blade tips rubbing the shroud ring.

Bearing Disorder

Provide cleaning and eliminate the cause for the ingress of the foreign matter.

Inspect and replace with new bearing.

Turbocharger experiences surging during operating.

Fouling of turbine nozzle, blades.

Engine Cylinder unbalance.

Note: Rapid Changes of the engine load, particularly during shut-down can cause turbocharger surging.

Cleaning of the turbine side of turbocharger as required.

Refer to Engine Builders

Instruction Manual.

Exhaust gas temperature higher than normal.

Fouling or damage to turbine nozzle or turbine blades.

Lack of air e.g.: dirty air filter.

Exhaust back pressure too high.

Charge air cooler dirty, cooling water temperature too high.

Engine fault in fuel injection system.

Cleaning the turbine side of the turbocharger or component replacement.

Clean as required.

Investigate cause.

Clean and adjust as Makers

Instruction Manual.

Charge air (boost) pressure lower than normal.

Pressure gauge faulty or connection to it is leaking.

Gas leakage at engine exhaust manifold.

Dirty Air filter, causing pressure drop.

Dirty turbocharger.

Turbine blades or nozzle ring damage.

Rectify.

See Engine Builders Instruction Manual.

Clean air as required.

Cleaning of complete turbocharger required.

Inspect and replace as necessary.

Charge air pressure (boost) higher than normal.

Pressure gauge reading incorrectly.

Nozzle ring clogged with carbon deposits.

Engine Overload, engine output higher than expected.

Rectify.

Clean as required.

Consult Engine Builders Instruction Manual.

Fault in engine fuel injection system.

Consult Engine Builders Instruction Manual.

Turbocharger Vibration Severe unbalance of rotor due to dirt or damaged turbine blades.

Bent rotor shaft.

Defective bearings.

Rebalance the rotor assembly.

Inspect and replace as necessary.

Inspect and replace as necessary.

TURBO OVERHAULING

The overhauling and servicing of a turbosupercharger is broadly divided into five parts which are:

Dismantling of the turbo

Cleaning of the turbo

Inspection of different parts

Repair and rotor balancing

Assembly of the turbo

DISMANTLING OF THE TURBO

Dismantling of a turbo requires trained personnel and special tools (allen keys, spanners, suspension yoke, support, etc). It is a complicated process and should be done very carefully after referring to the manufacturer’s instruction manual.

CLEANING OF THE TURBO

Cleaning work includes regular visual checks and the cleaning of parts to ensure the correct functioning of the turbo.

Outline of cleaning work

The following figure explains the various symbols used in the previous figure:

GAS CASING:

Deposits often form on the nozzle ring and the turbine blades. Impaired efficiency and performance of the engine are the result.

Thick and irregular deposits can also result in an un-permissible unbalance of the rotor.

Cleaning of the cooling water passage of gas outlet casing:

Commercial HCL of 5% concentration is used for cleaning and defurring. An inhibitor is added to reduce the corrosion of cast iron.

Neutralisation with 5% NaOH (alkaline) solution follows the acid wash.

Fresh water is used foe flushing/rinsing.

All casing gaskets are replaced.

Gas inlet casing:

Deposits are cleaned with soft wire brush and with either diesel/kerosene + 20% mineral oil solution (80/20 solution).

BEARING CASING:

Cleaning of the sealing air ducts:

The carbon deposits are dissolved and cleaning is done with the help of flexible wire for ensuring free passage.

Compressed air is used to check that the sealing air ducts in the bearing casing are unobstructed / unchoked.

Oil Passages:

It is cleaned with 80% kerosene/diesel + 20% mineral oil solution (i.e. 80/20 solution).

AIR OUTLET CASING:

The deposits are cleaned with soft wire brush and 80/20 solution.

ROTOR PARTS:

The turbine blades can be cleaned by glass bead blasting. The seating areas for compressor wheel set, thrust bearing and floating bushes (Bearing compressor side + Turbine side) are protected by means of rubber sleeve. The cleaning of the compressor wheel set is carried out with 80/20 solution and therefore with malmal (piece of cloth).

Rotating parts are thoroughly cleaned uniformly as uneven residual deposits lead to unbalance.

BEARING PARTS:

All bearing parts, bearing covers are cleaned in 80/20 solution and with malmal (piece of cloth). Special care is taken to clean the carbon deposits from the “O” ring grooves and the oil supply/oil drain lines.

INSPECTION OF THE TURBO:

After dismantling and cleaning of the turbo, it is inspected for any faults. All the clearances and blade conditions are checked and a note of all the repair work needed is made.

REPAIR AND BALANCING OF ROTOR:

Various parts of the turbo are repaired as necessary. The rotor is examined carefully and any distorted turbine blade is ground with a grinder so that it is smooth again. The rotor is then checked if it is unbalanced and is balanced on a Rotor Balancing Machine if needed.

In the course of manufacture, following parts are balanced individually:

Shaft

Sets of compressor wheel

While the engine is running, many reasons may cause unbalance to the rotor:

Mechanical damages on the rotor, i.e. foreign bodies.

Uneven deposits of layer of dirt/carbon.

Abrasion on the compressor or the turbine caused by hard particles in the intake air or in the exhaust gas.

Balancing must be done when:

Rotating components feature mechanical damages.

After reblading of turbine.

After repairs on the inducer or compressor wheel.

After replacing the inducer or compressor wheel.

Balancing is not required when:

A new bladed shaft is assembled into the turbocharger.

If, due to a change of specification, the set of wheels has to be changed for a new one.

ABRO ROTOR BALNCING MACHINE

GE ROTOR ON BALANCING MACHINE

TURBO RUNDOWN TIME

The Turbo Rundown Time (TRD) of a turbo is the total time taken by the turbo to come to a standstill, measured from the instant the crankshaft of the engine stops. This time should be within a certain limit prescribed by the manufacturer. If not so, it indicates a fault in the turbo. The rundown times of different turbos have been mentioned earlier.

Turbo Rundown Test (for WDM-2 Loco)

This test is to be conducted if the Booster (Turbocharger in WDM-2 pidgin) is not developing proper pressure during a run.

1. Secure the loco: Keep the A9 (Train Brake lever) in released condition; keep the SA9 (Loco brake lever) in an applied condition; switch off the GF (Generator Field); keep the reverser in neutral condition; and put the ECS (Engine control switch) in the run mode.

2. The driver should climb on top of the hood and sight the turbine of the turbocharger through the chimney.

3. The assistant should raise the engine to 4th notch rpm and allow the engine to stabilize in speed.

4. As the engine begins to stop turning, the assistant must quickly get down and come to the hood door to the Expressor.

5. He must give a signal to the driver as to the instant the huge engine stops rotating by looking at the crankshaft of the engine coupled to the expressor.

6. The driver must count the number of seconds the exhaust turbine takes to come to a stop, from the instant the engine has come to a standstill.

7. If the turbine (which revolves at 18,000 to 19,000 rpm) takes more than 90 seconds then it is a good turbocharger, any reduction in the period of spinning down is an indication of a faulty turbo.

TURBO SUPERCHARGER AND ITS WORKING PRINCIPLE The exhaust gas discharge from all the cylinders accumulate in the common exhaust manifold at the end of which, turbo- supercharger is fitted. The gas

under pressure there after enters the turbo- supercharger through the torpedo shaped bell mouth connector and then passes through the fixed nozzle ring. Then it is directed on the turbine blades at increased pressure and at the most suitable angle to achieve rotary motion of the turbine at maximum efficiency. After rotating the turbine, the exhaust gas goes out to the atmosphere through the exhaust chimney. The turbine has a centrifugal blower mounted at the other end of the same shaft and the rotation of the turbine drives the blower at the same speed. The blower connected to the atmosphere through a set of oil bath filters, sucks air from atmosphere, and delivers at higher velocity. The air then passes through the diffuser inside the turbo- supercharger, where the velocity is diffused to increase the pressure of air before it is delivered from the turbo- supercharger.

Pressurising air increases its density, but due to compression heat develops. It causes expansion and reduces the density. This effects supply of high-density air to the engine. To take care of this, air is passed through a heat exchanger known as after cooler. The after cooler is a radiator, where cooling water of lower temperature is circulated through the tubes and around the tubes air passes. The heat in the air is thus transferred to the cooling water and air regains its lost density. From the after cooler air goes to a common inlet manifold connected to each cylinder head. In the suction stroke as soon as the inlet valve opens the booster air of higher pressure density rushes into the cylinder completing the process of super charging.

The engine initially starts as naturally aspirated engine. With the increased quantity of fuel injection increases the exhaust gas pressure on the turbine. Thus the self-adjusting system maintains a proper air and fuel ratio under all speed and load conditions of the engine on its own. The maximum rotational speed of the turbine is 18000/22000 rpm for the Turbo supercharger and creates max. Of 1.8 kg/cm2 air pressure in air manifold of diesel engine, known as Booster Air Pressure (BAP). Low booster pressure causes black smoke due to incomplete combustion of fuel. High exhaust gas temperature due to after burning of fuel may result in considerable damage to the turbo supercharger and other component in the engine.

MAIN COMPONENTS OF TURBO-SUPERCHARGER

Turbo- supercharger consists of following main components.

Gas inlet casing. Turbine casing. Intermediate casing Blower casing with diffuser Rotor assembly with turbine and rotor on the same shaft.

ROTOR ASSEMBLY

The rotor assembly consists of rotor shaft, rotor blades, thrust collar, impeller, inducer, centre studs, nosepiece, locknut etc. assembled together. The rotor blades are fitted into fir tree slots, and locked by tab lock washers. This is a dynamically balanced component, as this has a very high rotational speed.

LUBRICATING, COOLING AND AIR CUSHIONING

LUBRICATING SYSTEM

One branch line from the lubricating system of the engine is connected to the turbo- supercharger. Oil from the lube oils system circulated through the turbo- supercharger for lubrication of its bearings. After the lubrication is over, the oil returns back to the lube oil system through a return pipe. Oil seals are provided on both the turbine and blower ends of the bearings to prevent oil leakage to the blower or the turbine housing. COOLING SYSTEM

The cooling system is integral to the water cooling system of the engine. Circulation of water takes place through the intermediate casing and the turbine casing, which are in contact with hot exhaust gases. The cooling water after being circulated through the turbo- supercharger returns back again to the cooling system of the locomotive.

AIR CUSHIONING

There is an arrangement for air cushioning between the rotor disc and the intermediate casing face to reduce thrust load on the thrust face of the bearing which also solve the following purposes. It prevents hot gases from coming in contact with the lube oil.

It prevents leakage of lube oil through oil seals.

It cools the hot turbine disc.

Pressurised air from the blower casing is taken through a pipe inserted in the turbo- supercharger to the space between the rotor disc and the intermediate casing. It serves the purpose as described above.

AFTER COOLER

It is a simple radiator, which cools the air to increase its density. Scales formation on the tubes, both internally and externally, or choking of the tubes can reduce heat transfer capacity. This can also reduce the flow of air through it. This reduces the efficiency of the diesel engine. This is evident from black exhaust smoke emissions and a fall in booster pressure.

Fitments of higher capacity Turbo Supercharger- following new generation Turbo Superchargers have been identified by diesel shed TKD for 2600/3100HP diesel engine and tabulated in table 1.

TABLE 1

TYPE POWER COOLING1.ALCO 2600HP Water cooled2.ABB TPL61 3100HP Air cooled3.HISPANO SUIZA HS 5800 NG 3100HP Air cooled4. GE 7S1716 3100HP Water cooled5. NAPIER NA-295 2300,2600&3100HP Water cooled6. ABB VTC 304 2300,2600&3100HP Water cooled

TURBO RUN –DOWN TEST

Turbo run-down test is a very common type of test done to check the free running time of turbo rotor. It indicates whether there is any abnormal sound in the turbo, seizer/ partial seizer of bearing, physical damages to the turbine, or any other abnormality inside it. The engine is started and warmed up to normal working conditions and running at fourth notch speed. Engine is then shut down through the over speed trip mechanism. When the rotation of the crank shaft stops, the free running time of the turbine is watched through the chimney and recorded by a stop watch. The time limit for free running is 90 to 180 seconds.

Low or high turbo run down time are both considered to be harmful for the engine.

ROTOR BALANCING MACHINE

A balancing machine is a measuring tool used for balancing rotating machine parts such as rotors of turbo subercharger,electric motors,fans, turbines etc. The machine usually consists of two rigid pedestals, with suspension and bearings on top.The unit under test is placed on the bearings and is rotated with a belt. As the part is rotated, the vibration in the suspension is detected with sensors and that information is used to determine the amount of unbalance in the part. Along with phase information, the machine can determine how much and where to add or remove weights to balance the part.

ADVANTAGES OF SUPER CHARGED ENGINES

A super charged engine can produce 50 percent or more power than a naturally aspirated engine. The power to weight ratio in such a case is much more favorable.

Better scavenging in the cylinders. This ensures carbon free cylinders and valves, and better health for the engine also.

Better ignition due to higher temperature developed by higher compression in the cylinder.

It increases breathing capacity of engine

Better fuel efficiency due to complete combustion of fuel .

Defect in Turbochargers

Low Booster Air Pressure (BAP).

Oil throwing from Turbocharger because of seal damage or out of clearance.

Surging- Back Pressure due to uneven gap in Nozzle Ring or Diffuser Ring.

Must change components of Turbocharger.

Intermediate casing gasket. Water outlet pipe flange gasket. Water inlet pipe flange gasket. Lube Oil inlet pipe rubber ‘o’ ring. Turbine end Bearing. Blower end Bearing. Chimney gasket. Rubber ‘o’ Ring kit. Spring Washers. Lock Washer Rotor Stud.