ELECTROMAGNETIC RAILGUN

(EMRG)

Submitted by:-

Navin Kumar

1144536

D4EE

TABLE OF CONTENTS:

1. Introduction.

2. Literature review

3. Technology and working

3.1 Physics of working

4. Components

5. Limitations

6. Future Scope

7. Conclusion

1.INTRODUCTION

A railgun is an electrically powered

electromagnetic projectile launcher

based on similar principles to

the homopolar motor. A railgun

comprises a pair of parallel

conducting rails, along which a

sliding armature is accelerated by

the electromagnetic effects of a

current that flows down one rail,

into the armature and then back

along the other rail.

Lorentz force: the Lorentz force is

the combination of electric and

magnetic force on a point

charge due to electromagnetic

fields. F=iL*B

2.LITERATURE REVIEW

In 1918, French inventor Louis Octave Fauchon-

Villeplee invented an electric cannon which is an early form of

railgun.

In 1944, during World War II, Joachim Hänsler of Germany's

Ordnance Office built the first working railgun. By late 1944 enough

theory had been worked due to which demanded a muzzle velocity

of 2,000 m/s (6,600 ft/s) and a projectile containing 0.5 kg (1.1 lb) of

explosive. The guns were to be mounted in batteries of six firing

twelve rounds per minute. It was never built.

When details were discovered after the war it aroused much interest

and a more detailed study was done, culminating with a 1947 report

which concluded that it was theoretically feasible, but that each gun

would need enough power to illuminate half of Chicago.

3.TECHNOLOGY AND

WORKING

3.1 Physics of Working

4.COMPONENTS

1. Power supply source

Capacitors banks : 1. A capacitor bank is a grouping of several identical capacitors interconnected in parallel or in series with one another.

2. Capacitor banks are also used in direct current (DC) power supplies to increase stored energy capacity and improve the ripple current capacity of the power supply.

Compulsators (Compensated pulsed alternator) : 1. The compulsator is used like a capacitor, to gather energy from a low-power source and store it, then generate a high-power output for a short period.

2. The windings of a compulsator are different from those of a normal alternator in being designed for minimal inductance. This allows the current in the windings to change very rapidly, which is why this "compensation" makes it better at delivering pulses.

Capacitor bank

Energy produced by

the capacitor bank in

railgun is approx. 50

MJ

Inductors are also

connected is series

with every bank as to

provide delay in the

discharging current.

Compulsator (compensated pulsed power

supply)

It is Curtiss Wright

Compulsator

Stores produced

current in armature of

the alternator.

Currently in

production.

2. Conducting rails

These are generally made of copper.

Oxygen free copper.

Copper has high melting point as compare to aluminium.

Support rails are installed along with rails to provide additional

mechanical strength, due to excessive force acting on conducting

rails.

These should also be resistant to corrosion, high machinebility.

3. Projectile

There are three types of configurations for projectile :-

1. Conducting type

2. Plasma type

3. Hybrid type

1.Conducting type

The first method simply involves using a projectile that is a conductor. Because the projectile itself conducts electricity and rides along the rails, it closes the current loop and can be launched from the gun as it is, with no additional components.

The major drawback of this method is that the high heat and current density involved in launching the projectile from the gun can cause the projectile to weld to the rails.

If a projectile welds itself to the rails the current loop remains closed and in addition to ruining the rails and the projectile, serious damage may occur in the power supply.

2. Plasma type

The second method of launching the projectile involves a

nonconductive projectile and a plasma armature.

In this method a small filament is placed behind a nonconductive

projectile. When power is applied to the rails, the filament vaporizes

and an arc of conducting plasma is formed between the two rails.

This arc is then accelerated down the barrel by the Lorentz force,

pushing the projectile as it goes. This method solves the problem of

projectile welding, but in practice it is somewhat difficult to

implement.

3. Hybrid type

It is the combination of above to configurations.

In this a sabot is used which is conductive casing used to hold tungsten armature.

The plasma gas is formed behind the armature but also a conductive sabot is used.

This type of configuration is currently using in today’s electromagnetic railgun.

5. LIMITATIONS

One of the biggest problems is with maintaining the structural integrity of the rails as they undergo such stressful conditions.

The thermal management of the entire system, especially as the rails increase in size needs to improve.

The pulsed power unit and supply could be compact and decreased in size, as it encompasses most of the system.

The system is bulky.

Charging time of capacitors is high.

Risk of welding of projectile, which could lead to serious damage of system.

6. FUTURE SCOPE

Launching cargo into spaceBecause of the excessive acceleration, however, railguns could not be

used to launch humans or any other acceleration sensitive cargo

into space. In order to be practical for launching cargo into space,

railguns would need to be able to attain muzzle velocities of 11 km/s

with cargo much heavier than small projectiles. In comparison,

effective ballistic missile interception requires muzzle velocities of

approximately 12 km/s.

Nuclear fusionto investigate the possibilities of accelerating particles into a fusion

reactor using a railgun. The high velocity of the particles would

cause instantaneous fusion with target particles upon collision.

Satellite guided projectilesCosting up to $25000 per projectile. Making easy to destroy targets

from long distances more accurately.

7. CONCLUSION

In conclusion, railguns are a very intriguing technology and have

several exciting potential applications.

While the physics of the electromagnetic phenomena are fairly

simple, implementation of the technology has proven to be very

difficult.

The future of railgun development depends not only on continued

development of technology, but also on continued financial support

of railgun research.

Thank you (Any queries)