“VAN DE GRAAFF GENERATOR”
A PROJECT REPORT (UDP)
Submitted by
NISARG R KODINARIYA 140280109058
RISHABH R PANDYA 140280109060
MEET J PATEL 140280109077
RIPAL K PATEL 150283109021
Guided by
JITEN K CHAWDA
In fulfillment for 7th Semester
Of
BATCHLOR OF ENGINEERING
IN
ELECTRICAL ENGINEERING
Gujarat Technological University, Ahmedabad
2017 – 2018
CERTIFICATE
Date: / / 2017
This is to certify that the dissertation entitled “VAN DE GRAAFF GENERATOR” has been carried out by NISARG R KODINARIYA, RISHABH R PANDYA, MEET J PATEL, RIPAL K PATEL under my guidance in fulfillment of the degree of Bachelor of Engineering in Electrical from Gujarat Technological University, Ahmedabad during academic year 2017-2018.
Guided by:
Jiten K Chawda
Prof. Prof.
Head of the Department Director
CERTIFICATE OF APPROVAL
The Project entitled
“VAN DE GRAAFF GENERATOR”
Submitted By
NISARG R KODINARIYA 140280109058
RISHABH R PANDYA 140280109060
MEET J PATEL 140280109077
RIPAL K PATEL 150283109021
As a partial fulfillment of the requirement for the 7th Semester of
BACHELOR OF ENGINEERING
In the field of
ELECTRICAL ENGINEERING
Is here by approved.
Internal Examiner External Examiner
Date:
Place:
PMMS Completion Certificate
activities at PMMS portal of GTU.
Plagiarism result Certificate
Undertaking About Originality Of Work
ACKNOWLEDGEMENT
ABSTRACT
LIST OF TABLES
Table No Table Description Page No.
LIST OF FIGURES
Figure No Figure Description page No
Figure 1 AEIOU canvas
Figure 2 Empathy summary
Figure 3 Ideation canvas
Figure 4 Product Development canvas
Figure 5 Electric Potential of a charged sphere
Figure 6a Charge Carrying belt used in van de graaff generator
Figure 6b Pulley used in van de graaff generator
Figure 7a Schematic diagram van de graaff generator
Figure 7b Van de graaff generator with discharger
Figure 8 Actual model of van de graaff generator
Figure 9a Shows an aircraft having a radar cross-section reducing system constructed in accordance with this invention
Figure 9b Shows a sectional view, partially schematic, of part of the radar cross-section reducing system of Figure 11a
Figure 10a Schematic diagram of electrostatic precipitator.The negative electric potential maintained on the central coiled wire creates an electrical discharge in the vicinity of the wire
Figure 10b The air pollution when the electro static precipitator is on
Figure 10c The air pollution when the electro static precipitator is off
Figure 11 The xerographic process
LIST OF ABBREVIATIONS
INDEX
Topic Page No.
Chapter 1 Introduction
1.1 Introduction
1.2 Aim and objectives of the project
1.3 Problem Specifications
1.4 Brief literature review and Prior Art Search (PAS) about the project
1.5 Materials / Tools required.
Chapter 2
2.1 Observation record sheets
2.1.1 AEIOU framework
2.1.2 Empathy canvas
2.1.3 Ideation canvas
2.1.4 Product development canvas
Chapter 3
3.1 Principle of operation
3.2 Construction
3.3 Working
Chapter 4
4.1 Uses of Van De Graaff Generator
4.2 Other application of electrostatic principle
Reference
CHAPTER 1
- Introduction
The Van de Graaff generator is an electrostatic precipitator which uses a moving conveyor belt to gather electric charge on a hollow metal surface on the top of an insulated system, creating high electric potentials. It produces very high potential direct current electricity at low current level. It was invented by American scientist Robert J. Van de Graaff during 1929.The voltage difference achieved by modern Van de Graaff generators can be as much as 6 megavolts. The small version can produce on the order of 1 lac volts and can store enough energy which can produce a visible spark. Small Van de Graaff machines are produced for entertainment purpose, and for physics education to teach electrostatics and electrostatic principle; larger ones are displayed in some science museums and school laboratories.
The Van de Graaff generator was developed as a particle accelerator for physics research and development, its high voltage is used to accelerate subatomic particles to great speeds in an evacuated and insulated tube. It was the most powerful type of accelerator of the 1930s until the cyclotron was invented. Van de Graaff generators are still used as accelerators to generate energetic particle and x-ray beams for nuclear medicine research and development. In order to double the voltage, two generators are usually used together, one generating positive and the second negative potential; this is termed a tandem Van de Graaff accelerator or generator. The voltage produced by an open-air Van de Graaff generator is limited by arcing and corona discharge to about 5 MV.
- Aim and objectives of the project
A Van de Graaff generator is an electrostatic influence machine which uses a moving belt to accumulate electric charge on a hollow metal globe on the top of an insulated column, creating very high electric potentials. It can produce very high voltage direct current electricity at low current levels.
- Problem Specifications
This invention relates to electrostatic generators for the production of direct current voltages, and also to apparatus including an electrostatic generator and the electrical device, such as an X-ray tube, operated thereby
- Brief literature review and Prior Art Search (PAS) about the project.
An electrostatic precipitator used to produce a high electrostatic voltage, usually in the megavolt range. It consists of a large metal spherical-shaped electrode mounted on a hollow insulating support. An insulating belt runs through the support from the base to a pulley within the hollow metal globe. In the original model, charge is sprayed by point discharge from brush, held at a potential of about 8 kV, on to the bottom of the belt. A brush near the upper belt pulley removes the charge from the belt and passes it to the outer surface of the hollow metal globe. The voltage produced by the device is proportional to the radius of the hollow metal globe. A typical device with a terminal having a radius of 1 m will produce about 1 MV. Terminals can be made smaller, for a given voltage, by enclosing the apparatus in nitrogen at a pressure of 10–20 atmospheres to reduce sparking. Generators having a positive or negative ion source are fitted with an evacuated tube through which the particles can be accelerated for research purposes. Machines having an electron source are used for various medical and industrial purposes. The generator was invented by R. J. Van de Graaff (1901–67).Modern patterns of the generator have a chainlike belt of alternate links of metal and insulator. The metal links are charged by contact with a metal pulley, and discharge to the dome in the same way. This permits much higher current drain that the point discharge.
- ) Materials / Tools required.
1)Hollow Metal Globe
2)Upper Electrode
3)Upper Pulley(Acrylic glass)
4)Side of the belt with positive charges
5)Opposite side of the belt with negative charges
6)Lower pulley (metal)
7)Lower electrode (Ground)
8)Spherical device with negative charges
9)Brush
10)DC motor
CHAPTER 2
2.1 OBSERVATION RECORD SHEETS
2.1.1 AEIOU Framework
AEIOU is the abbreviation of Activities, Environment , Interaction, Objects and User.
1) Activities-The purpose of van de graaff generator is to produce high electrostatic charge and following activities are done in over project,
(1) Charge Supply System (2) Maintenance
(3) High voltage Testing (4) Impulse Testing
(5) Control Room (6) Safety
(7) Supervision (8) Mixing
2)Environment-The surrounding around the plants/factory/industry as well as the environment in the work area is understood.
(1) Sunny (2) Quite
(3) Less humid (4) Wide area required
(5) Clean and No dusty (6) Safe environment
3) Interactions– The interactions taking place inside the campus. It may be between the workers, all campus faculty, HOD, school teachers, etc. who are connected to household solid waste.
4) Objects – The objects essential in the design of van de graaff generator is metal globe, brushes, electrodes, charge carrying belt, DC motor.
5) Users– The van de graaff generator is useful for industrial experiments, research facilities, school, colleges, scientists, hospitals.
Figure 1
2.1.2 Empathy Canvas
Figure 2
2.1.3 Ideation Canvas
Figure 3
2.1.4 Product Development Canvas
Figure 4
CHAPTER 3
3.1) PRINCIPLE OF OPERATION:
The rubber belt is driven by the plastic pulley and a charge is induced on the surface of the belt as the rubber belt leaves contact with the plastic pulley. This charge on the outer surface of the belt is positive relative to the lower ‘comb’ which is connected to earth potential.
The belt carries the charge to the dome. The inside surface of the belt touches the metal pulley to be at the same potential as the dome and the positive charge across the belt thickness is removed from the belt by the sharp points of the upper ‘comb’. This charge from the belt is added to the dome’s existing charge.
The outer surface of the dome acquires a positive charge in respect to earth. This ‘charge pumping’ effect is cumulative until a voltage on the large dome is sufficient to cause a spark discharge between the dome and the discharge ball.
If we have a large conducting spherical shell of radius ‘R’ on which we place a charge Q, it spreads itself uniformly all over the sphere. The field outside the sphere is just that of a point charge Q at the centre, while the field inside the sphere vanishes. So the potential outside is that of point charge and inside it is constant.
The potential inside the conducting sphere =
Now suppose that we introduce a small sphere of radius ‘r’, carrying a charge q, into the large one and place it at the centre. The potential due to this new charge has following values.
Potential due to small sphere of radius r carrying charge
Potential at the surface of large shellof radius R
.
Taking both charges q and Q in to account we have for the total potential V and the potential difference given by,
Figure 5
Now assume that q is positive. We see that, independent of the amount of charge Q that may have accumulated on the larger sphere, it is always at a higher potential: the difference V(r) – V(R) is positive. The potential due to Q is constant upto radius R and so cancels out in the difference.
This means that if we connect the smaller and larger sphere by a wire, the charge q on the former will immediately flow on to the matter, even though the charge Q may be quite large. The natural tendency is for positive charge to move higher to lower potential. Thus, provided we are somehow able to introduce the small charged sphere into the larger one, we can in this way pileup larger and larger amount of charge on the latter. The potential of the outer sphere would also keep rising, at least until it reaches the breakdown field of air.
3.2) CONSTRUCTION:
The generator is robustly designed, both motor drive and charging belts are easily changed. The housing contains the motor with a belt drive to a plastic pulley, speed control and power switch. The plastic pulley drives the rubber belt over a roller inside the large stainless steel dome and the tension of the main belt is adjustable. Transparent and easily removable covers protect both the motor drive belt and the charging belt.
The support columns are clamped firmly and they may be used to carry the unit. The discharge ball is screwed to a long support rod which provides an insulated handle and an earth connection terminal. This rod may be located in the adjustable support provided on the rear face of the housing to hold the discharge ball at the correct position relative to the dome for prolonged ‘hands off’ use.
The power and speed of the motor may be adjusted to demonstrate that work is done when the charge on the belt is transported from a place of low potential to a place of high potential. The belt can be seen to slow down as the charge increases on the large dome.
Belts and Pulleys
A flexible belt made from insulating material is connected with two pulleys and is continuously moving. This motion can produce charge on the hollow cylinder. Material of two rollers are different i.e acrylic and metal.
Figure 6a and Figure 6b
Comb
Charges are collected and removed from the belt by use of combs. Combs are situated near the pulleys so that it can scratch the insulating belt to collect or remove the charge.combs can be made from stretched wire of copper or sharp serrated edge. Lower comb are maintained at earth potential and is a drain for the negative charges so positive charges carried upwards to the
Figure 7a Figure 7b
Collecting sphere
The upper comb is connected to a hollow sphere whose electrical capacity is proportional to its radius, will collect and store the charges on its outer metallic surface. Discharge can be done by two ways, mainly by conduction to nearest earth object or by breakdown of surrounding air.
Figure 8
Charging current
This process will continue as long as the belt moves. The charging current is normally a few mA and potential difference achieved by small generators will be 100-150 kV and by larger generators up to about 300 kV.
The whole apparatus
The mechanical arrangement of the belt/roller system/pulley is very simple and robust. The lower pulley is driven either manually or by motor. This pulley can be mounted directly on the motor spindle. In small models, fixed speed, shaded-pole IM are usual Whereas in bigger models often incorporate small H.P. variable-speed motors like sewing machine with carbon brushes, control is done by two method i.e. simple rotary rheostat or a solid state circuit. The motors, control switches and mains input socket are housed in a metal or plastic enclosure.
The support column for the collecting sphere must be made from insulating material like simple PVC plastic rod or acrylic tube or a pair of acrylic strips with separators. In some models the belt is enclosed within a plastic pipe with “windows” along its length.
Since the diameter of the collecting sphere determines the maximum p.d. (voltage) achievable, large spheres are mounted on taller columns to be more remote from the earth motor and control box. Machines are usually supplied with a “discharger”, often another, smaller, sphere mounted on a metal rod that has to be earthed to draw sparks from the collecting sphere.
3.3) WORKING
The initial start given to van de graaff is by giving the first comb B1 a positive potential by a strong source of near about 104 Volts. Electric wind having a positive charge will be generated. Production of wind occurs due to the discharging of charge from sharp edges. Conveyor belt moves continuously and will reach the hollow sphere on moving. When the belt will reach the sphere an induced negative charge will be produced on the sharp edges of comb B2. At once a induced positive charge will be produced on the second side of the comb B2. After this shifting of the charges,it will be transferred to hollow sphere S. Similarly, due to the discharging action of B2, wind will be generated but this will be negatively charged. The negatively charged wind helps us to make the positively charged belt neutral. After this the conveyor belt will be totally discharged. Again after one rotation, the conveyor belt will come down. It will take the positive charge from comb B1. Then again this charge will be taken by comb B2.
The above process repeats again and again and again. Due to the repetition the charge will start collecting on the hollow sphere S. The air present around the hollow sphere S will start ionizing when the potential of the spherical belt will cross the value of 3*106. 3*106 is the value of the air’s breakdown field. When the ionization of air starts then side by side leakage of charge will also occur. As the generator is packed into a steel compartment system filled with gas such as methane or nitrogen. So, leakage is reduced by this steel chamber. The larger the hollow sphere and the farther it is from ground, the higher will be its final potential.
3.4) OPERATING CONDITIONS:
The best results will be obtained in a dust-free atmosphere of low humidity and with absolutely clean and smooth domes, support rails and cover. The machine should be placed at least 2 meters from walls, light fittings, plumbing, etc. particularly if these objects present sharp corners or edges. The discharge ball should be earthed by connecting to the terminal on the base of the unit with the flexible wire supplied.
During prolonged operation, the discharge ball rod (with or without the earth cable attached) may be ‘parked’ by inserting into the hole in the adjustable holder mounted on the rear of the housing.
To adjust the ‘parking’ angle of the discharge ball, use the rod to twist the holder on the rear panel. If desired, the discharge ball’s insulated rod may be held in the hand, but the earthing cable must be attached.
Chapter 4
4.1)Uses of van de graaff generator
They are used where a very high voltage at very low current is needed. For example, to accelerate electrons or ions to high speed, a form of particle accelerator. Accelerating electrons to sterilize food and process materials, accelerating protons for nuclear physics experiments, producing energetic X-ray beams in nuclear medicine, physics education, and entertainment. One of Van de Graaff’s accelerators used two charged domes of sufficient size that each of the domes had laboratories inside – one to provide the source of the accelerated beam, and the other to analyze the actual experiment. The power for the equipment inside the domes came from generators that ran off the belt, and several sessions came to a rather gruesome end when a pigeon would try to fly between the two domes – causing them to discharge (The accelerator was set up in an airplane hangar)potential difference up to 14 million volts could be achieved at the terminal of a tandem that used a tank of high pressure sulfur hexafluoride (SF6) gas to prevent sparking by trapping electrons. This allowed the generation of heavy ion beams of several tens of mega-electron-volts, sufficient to study light ion direct nuclear reactions. The highest potential sustained by a Van de Graaff accelerator is 25.5 MV, achieved by the tandem at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. The Nuclear Structure Facility, or NSF at Daresbury Laboratory, was proposed in the 1970s, commissioned in 1981 and opened for experiments in 1983. It consisted of a tandem Van de Graaff operating routinely at 20 MV, housed in a distinctive building 70 metres high. During its lifetime it accelerated 80 different ion beams for experimental use, ranging from protons to uranium. Van de Graaff generator can produce a voltage of over 10 million volts on its spherical cover. In nuclear physics, such a high voltage can be used to accelerate various kinds of charged particles, like protons, electrons etc. Moreover, the generator can be used to demonstrate many interesting phenomena of static electricity. For examples, it can make your hair stand upright, attract a metal ball or a polystyrene ball, produce an electric spark, and generate electric wind to set a mini-windmill into rotation. Through these phenomena, we can understand more about the nature of static electricity.
1)Wave attenuation in aircrafts and radar
Study shows that the radar cross-section of the object is reduced by applying a high positive DC static potential to the outer surface or skin of the object. The DC potential is preferably above 200,000 volts. The high DC potential reduces the reflectivity of radar electromagnetic waves from a radar transmitter.
One method for applying the DC potential is by mounting at least one Van de Graaf generator to the object. Van de Graaf generators are well-known devices, used primarily for experimental and educational purposes. A Van de Graaf generator has a belt that is engaged at one end by a rotating pulley of nonconductive material, such as a plastic, and the other engaged by a rotating pulley of a conductive material, such as aluminum. One of the pulleys is driven to rotate the belt. Frictional rubbing between the belt and pulleys occurs due to the curvature of the belt as it passes around the pulleys. The rotation of the belt rotates creates a static potential. A positive brush at one end picks up the positive charges from the belt and deposits them on a metal collector or dome. A negative brush at the other end picks off the negative charges from the belt and deposits them on a ground section. The charges can accumulate up to a high level, typically 200,000 volts.
In application to an aircraft, a number of Van de Graaf generators are mounted in a housing or pod attached to each wing. The collector locates at the forward end and the ground section locates at the rearward end in the shape of a fin. The collector is in electrical contact with the outer skin of the wing. The combined Van de Graaf generators create voltages in excess of 200,000 volts. The high DC potential is applied uniformly throughout the skin of the aircraft.
Negative dissipators or wires are attached to the ground section. During flight, the air stream flowing past the dissipators will cause the negative charges to dissipate from the ground section.
Also, to discharge the high static potential on the aircraft before it lands, preferably positive dissipators are also mounted to the aircraft trailing edges. The positive dissipators are separated by an insulator section so that they do not function to dissipate the positive charges unless connected by the closing of a switch. The switch, when closed, connects the positive dissipators to the skin of the aircraft to dissipate positive charges during flight. The switch is controlled by the pilot or by the aircraft flight control system.
It is not completely clear why the radar cross-section is reduced by the high DC potential. A theory is that in order to have good reflectivity of radar, free negative electrons need to be readily available on the object. If a high positive charge has been applied to the object, the negative electrons will not be free and present when electromagnetic radar waves strike the object. Consequently, the radar cross-section or reflectivity is reduced. The electromagnetic waves from a radar transmitter are attenuated upon striking the object.
Figure 9a Figure 9b
The invention has significant advantages. Considerable reduction in radar cross-section has been achieved with the application of the high positive static charge. The equipment used to apply the charge is relatively light in weight and not complex. The high static charge, having no current, poses no danger to humans or to other equipment on the aircraft.
2)For Nuclear Physics Measurement
The present report describes an EG-2 Van-de-Graaff generator that has built at the IAP NUU and has following parameters: accelerated proton energy is in a range of 0.3/2.0 MeV with monochromaticity of 104, beam current is 50nA/10uA.
Van-de-Graaff generators provides high monochromatic (~10-4) beams of various ions with currents of ~10-4A and energies that are continuously adjustable within a range of 0.1/10 MeV. These characteristics of the generators as well as compactness and simplicity of their construction and maintenance have led to a wide use of the generators for nuclear physics measurements.
Modern conceptions of nucleus structure and nuclear reactions nature have been considerably developed due to measurements at the Van-de-Graaff generators with energies
up to 10 MeV. An important information about density function of neutron spectra nuclear levels and about a nature of one-particle excited states of nuclei and their quantum characteristics were obtained when reactions of (p,n), (d,p) and (t,α) types were measured. Measurements of (α,p) = (p,α) type direct and back reactions were used to study nuclear systems symmetry features in regard to their time inversion. Fissionabilities of several tens of short-half-life heavy nuclei were studied by measuring (p,p’f)> (d,pf), (t,pf)> (α, α ‘f), (3He,df) and (t,αf) reactions. 3H(p,n), 7Li(p,n), 2 H(d,n), 3H(α,n) reactions are used to be sources of relatively low background, monoenergetic (continuously adjustable within a range of (0/20 MeV) neutron beams that are necessary for sensitive “limited white spectrum” neutron measurements.
The Van-de-Graaff generators occurred to be very useful for application studies. (p,a), (α,2n), (t,n) and (d,2n) reactions activation methods of detecting H, 2H, Li, Be, B, C, N, O admixtures, particle induced gamma-ray emission (PIGE) method, and particle induced X-ray emission (PIXE) one, as well as Rutherford backscattering (RBS) one based on the generators were developed. These methods all together provide detecting practically all of the chemical elements down to concentration of n.10-10g/g and depth and surface distribution of components with an accuracy of 0.1 um. Accelerated ions channeling method is developing for detecting crystal flaws and locating doped nuclei in crystal structure. Ion beams of the Van-de-Graaff generators have a wide use for microelectronic materials modifications. Since ninetieth of last century the generators have been modified for implanting ions of wide range that provides them to compete with ion mass-spectrometers successfully.
4.2)Other application of electrostatic principle
1)The Electrostatic Precipitator
One important application of electrical discharge in gases is the electrostatic precipitator. This device removes particulate matter from combustion gases, thereby reducing air pollution. Precipitators are especially useful in coal-burning power plants and in industrial operations that generate large quantities of smoke. This system are able to reduce 99%dust from smoke. A high potential difference (typically 40 to 100 kV) is maintained between a wire running down the center of a duct and the walls of the duct, which are grounded. The wire is maintained at a negative electric potential with respect to the walls, so the electric field is directed toward the wire. The values of the field near the wire become high enough to cause a corona discharge around the wire; the discharge ionizes some air molecules to form positive ions, electrons, and such negative ions as O2–. The air to be cleaned enters the duct and moves near the wire. As the electrons and negative ions created by the discharge are accelerated toward the outer wall by the electric field, the dirt particles in the air become charged by collisions and ion capture. Because most of the charged dirt particles are negative, they too are drawn to the duct walls by the electric field. When the duct is periodically shaken, the particles break loose and are collected at the bottom. In addition to reducing the level of particulate matter in the atmosphere, the electrostatic precipitator recovers valuable materials in the form of metal oxides.
Figure 10,10a,10b
2)Xerography and Laser Printers
The basic idea of xerography was developed by Chester Carlson, who was granted a patent for the xerographic process in 1940. The one feature of this process that makes it unique is the use of a photoconductive material to form an image. (A photoconductor is a material that is a poor electrical conductor in the dark but that becomes a good electrical conductor when
exposed to light.
The xerographic process is illustrated in Figure 11a to d. First, the surface of a plate or drum that has been coated with a thin film of photoconductive material (usually selenium or some compound of selenium) is given a positive electrostatic charge in the dark. An image of the page to be copied is then focused by a lens onto the charged surface. The photoconducting surface becomes conducting only in areas where light strikes it. In these areas, the light produces charge carriers in the photoconductor that move the positive charge off the drum. However, positive charges remain on those areas of the photoconductor not exposed to light, leaving a latent image of the object in the form of a positive surface charge distribution.
Next, a negatively charged powder called a toner is dusted onto the photoconducting surface. The charged powder adheres only to those areas of the surface that contain the positively charged image. At this point, the image becomes visible. The toner (and hence the image) are then transferred to the surface of a sheet of positively charged paper. inally, the toner is “fixed” to the surface of the paper as the toner melts while passing through high-temperature rollers. This results in a permanent copy of the original.
Figure 11
The xerographic process:
(a) The photoconductive surface of the drum is positively charged.
(b) Through the use of a light source and lens, an image is formed on the surface in the form of positive charges.
(c) The surface containing the image is covered with a negatively charged powder, which adheres only to the image area.
(d) A piece of paper is placed over the surface and given a positive charge. This transfers the image to the paper as the negatively charged powder particles migrate to the paper. the paper is then heat-treated to “fix” the powder.
(e) A laser printer operates similarly except the image is produced by turning a laser beam on and off as it sweeps across the selenium-coated drum.
Reference
- Basic Operation & Applications of Van de Graaff Generator Authors Prof.P.G.Mahajan , Prof. N. V. Patil, Prof. M. S. Shinde
- Boyd B. Bushman, Wave attenuation, United States patent, 13th May 1995.
- J. Van De Graaf, Electrostatic Generator, United States patent, 12th February 1935.
- High Voltage Engineering Authors Naidu M.S. and Kamaraju V Publisher Tata Macgrow hill
- High Voltage Engineering, Fundamentals Authors Kuffel. E., Zaengl W.S., Kuffel J. Publisher Butterworth Heinmann
- John G Trump, Robert W Cloud,Charge transferring means for high-voltage electrostatic apparatus, United states patent, 1st July 1947
- John G Trump, Apparatus for reducing destructive transients in electrostatic belt generators, United States patent, 21st January 1948
- Amrita Vishwa Vidhyapeetham University published website page on van de graaff generator
- A use of van de graaff generators for nuclear physics measurements, Paper published in The Third Eurasian Conference “Nuclear Science and its Application”, 5-8 October 2004
- Instruction Sheet of 400KV van de graaff generator by Industrial Equipment and Control pvt. Ltd.