INSTRUCTION SHEET
Cat: EM4143-001 (Controlled Torque)
The IEC VAN DE GRAAF GENERATOR is a modern, compact and robust instrument that is specially designed for student use in the classroom.
Power Input : 220/240V.AC 50/60 Hz.
Output: 200 kV under ideal conditions. Approx. 80 mm spark between balls.
Dimensions: Overall height: 650mm. Dome diameter: 200mm. Discharge ball 80mm. diam
Materials: Belt: rubber Width: 55mm. Cat: PA4143-002
Motor pulley is polypropylene and makes positive potential to the dome.
Drive: AC. Motor with electronic speed controller.
EM4143-001
Physical size: Weight: kg
Designed and manufactured in Australia by Industrial Equipment and Control Pty Ltd
Distributed by
Scientrific Pty Ltd
ABN 55 056 072 694
P O Box 420 Yamba NSW 2464
Phone (02) 6645 8111 Fax (02)66458125

INSTRUCTION SHEET
CONSTRUCTION:
The generator is robustly designed and is easily dismantled for servicing or for the maintenance of components. The housing contains the motor, plastic pulley, speed control and power switch. The plastic pulley, fitted to the motor shaft, drives the rubber belt over a roller mounted in ball bearings inside the large aluminium dome. The acrylic support column is firmly supported in place by the tension of the belt and it may be used to carry the unit if reasonable care is taken. The discharge ball is screwed to a long support rod which provides an insulated handle and an earthing terminal. This rod may be located in the hole provided in the housing to hold the discharge ball at the correct position relative to the main dome for prolonged 'hands off' use.
The power (torque) 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 is seen to slow down as the charge increases.
OPERATING CONDITIONS:
The best results will be obtained in a dust-free atmosphere of low humidity and with absolutely clean and smooth spheres and column. The machine should be placed about 2 metres 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 (without the earth cable attached) may be inserted into the hole in the housing and located by the peg fitted to the rear face of the housing. For adjustable spark gap, the rod may be held in the hand providing the earth cable is attached.
PRECAUTIONS: x Approach the machine with caution at all times. A spark discharge to the hand, although harmless, is a little painful.
x The discharge current that makes the spark from the dome, passes through the discharge ball to earth through the earth wiring of the mains socket on the wall. This short duration high current can make the earth potential of other power outlets rise above earth potential at each spark. It is advised that computers in the building are turned off when using a Van De Graaff.
Alternatively, the discharge ball should be earthed with a separate wire direct to an earth point in the building (a metal water pipe etc.) rather than through the panel terminal and then through the power outlet.
x Be sure that the discharge ball is the closest object to the main dome. Always stand behind the discharge ball or be seated well below the large dome.
x At spark gaps greater than 100mm care must be taken when altering the speed or when touching the base, as leakage through the air may cause a small discharge from the user's hand to the chassis.
x After switching off, always earth the large dome to discharge it before touching it with the hand.
x Handle the large aluminium dome gently since dents are difficult to remove and they reduce operating efficiency.
x Always hold the discharge ball support rod by the insulated handle provided. Always have the earth cable attached.
Designed and manufactured in Australia by Industrial Equipment and Control Pty Ltd
Distributed by
Scientrific Pty Ltd
ABN 55 056 072 694
P O Box 420 Yamba NSW 2464
Phone (02) 6645 8111 Fax (02)66458125

INSTRUCTION SHEET x Do not remove the access plug on the underside of the housing unless the unit is first disconnected from the power source.
x Since sunlight causes deterioration of rubber, the unit should always be stored in a well shaded place when not in use. Do not store in front of an unshaded window.
REFER TO THE DRAWING FOR PARTS IDENTIFICATION
MAINTENANCE:
CLEANING: Dirt and moisture cause poor performance:
The belt (N) may be removed and washed in warm soapy water, thoroughly rinsed and dried in a warm oven. The acrylic tube (F) may be cleaned by pushing a ball of cloth back and forth taking care not to damage or scratch the inside surface. Do not use solvents of any type . The surfaces of the pulleys (B & H) should be wiped with a cloth moistened with alcohol. Allow all components to dry before assembling the unit. Run with the dome removed until the unit begins to charge. Turn machine off, reposition the dome then turn machine on again.
The above procedure is a major cleaning operation and should be performed only when most adverse conditions demand it. A normal cleaning routine is to simply wipe the large dome, the small discharge ball and the outer surface of the acrylic tube with a soft lint-free cloth.
ASSEMBLY INSTRUCTIONS:
Components are: x 1 pce. Base housing sub-assembly with motor and controls (A).
x 1 pce. Mains power cable & plug x 1 pce. Acrylic support tube (F).
x 1 set Aluminium dome & pin (M) x 1 pce. Top pulley (H), support frame (L) and 'comb' (J) assembly.
x 1 pce. Discharge ball.
x 1 pce. Handle, with terminal, for discharge ball.
x 1 pce. Cable with 4mm plugs to connect discharge ball handle to base.
x 2 pcs. Rubber belt (N). (1 spare).
x 1 pce. Black plastic collar (G) for top of acrylic tube.
Remove the parts from the packing and check that all parts are present.
As supplied, the 200 kV. Van de Graaff machine is partly assembled. Complete the assembly as follows: x Invert the base housing and allow the rubber belt to hang vertically. Pass the acrylic tube (F) up over the belt (N) to allow the belt to fall freely inside the tube. Insert the end of the acrylic tube into the black plastic collar (E) mounted to the base. With the hand, reach into the lower mouth of the tube and grasp the free end of the belt.
Stretch it through the tube and hold it firmly. Invert the whole unit and stand it upright on the bench while still holding the belt.
Designed and manufactured in Australia by Industrial Equipment and Control Pty Ltd
Distributed by
Scientrific Pty Ltd
ABN 55 056 072 694
P O Box 420 Yamba NSW 2464
Phone (02) 6645 8111 Fax (02)66458125

INSTRUCTION SHEET x Pass the stretched belt through the black plastic collar (G) so that the collar fits over the upper end of the acrylic tube while still retaining the stretched belt with the fingers.
x Slip the top pulley and shaft assembly (H) into the loop of the belt and fit the two ends of the shaft into the two holes (I) provided in the ‘U’ shaped pulley mounting bracket (L). Locate and firmly press the two legs of the mounting bracket into the receptacles in the black plastic collar (G) so that it is supported rigidly. The belt should now be free to turn between the motor pulley (B) in the base housing and the upper pulley (H) in the dome.
x NOTE: The clear acrylic tube might be a firm fit inside the black plastic collars. If it is difficult to twist the upper black collar to align the belt, the collar can be tapped upwards with a solid object to loosen the fit to the acrylic tube. After twisting as required, press collar down firmly to the end of the acrylic tube.
x Swing the upper ‘comb’ (J) that is clipped to its support rod, so that it almost touches the belt. The upper comb must be on the same side of the belt as the lower comb in the base (C) and both combs should be on the front side of the machine. The belt should move upwards from the lower comb to the upper comb when viewed from the front.
x Invert the unit carefully and check the positioning of the lower comb (C). Rotate the belt by hand to check that the comb is very close to the belt but not touching it. Refit the bottom inspection plug (O). Re-check the upper comb position.
x Connect power and turn on main switch on the front panel. Adjust the speed to maximum. Check that the belt runs freely and that the combs are set close to the belt surface but not actually touching the belt.
x While running fast, place your finger close to the upper metal pulley support bracket
(L). If a fast repetitive spark about 20mm long tickles your finger, then the machine is performing well.
x Turn off the motor.
x Make sure the special ‘R’ shaped wire clip (R) is pressed into position on the socket with the straight leg in the groove provided. While holding the dome in position, feel the pin (M) inside the dome enter the socket. Gently press the dome down so that the pin (M) engages the socket and the ‘R’ clip presses firmly against the pin to stop the dome from wobbling.
x Attach the earth cable between the terminal on the discharge ball handle and the earth terminal on the front panel of the machine. Screw the discharge rod into the socket of the metal coated discharge ball. Tighten the discharge ball gently but firmly. Turn on the motor and hold the discharge ball about 100mm away from the large aluminium dome. Strong repetitive sparks should be obtained.
For belt removal and installation, refer to the above assembly instructions for method.
Designed and manufactured in Australia by Industrial Equipment and Control Pty Ltd
Distributed by
Scientrific Pty Ltd
ABN 55 056 072 694
P O Box 420 Yamba NSW 2464
Phone (02) 6645 8111 Fax (02)66458125

INSTRUCTION SHEET
Designed and manufactured in Australia by Industrial Equipment and Control Pty Ltd
Distributed by
Scientrific Pty Ltd
ABN 55 056 072 694
P O Box 420 Yamba NSW 2464
Phone (02) 6645 8111 Fax (02)66458125

INSTRUCTION SHEET
PRINCIPLE OF OPERATION:
The rubber belt (N) is driven by the plastic pulley (B) and a charge is induced on the surface of the belt. This charge on the outer surface of the belt is positive relative to the lower 'comb' (C) which is connected to earth potential at the motor. Having been carried to the dome, the positive charge is removed from the belt by the sharp corner of the 'comb' (J) which is very close to the belt before
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 ball is sufficient to cause a spark discharge between the two balls.
USEFUL OBSERVATIONS:
1. Discharge rates, colours and intensities at various spark gaps and motor torques.
2. Pull of attraction between balls of opposite polarity.
3. Corona discharge from tip of discharge ball support rod.
4. Check polarity and measure actual current flow with 0-25 micro-amp meter. This current measurement is a good check on the performance of the unit. A unit that will perform well and charge at a high rate and provide rapid large sparks will have a short circuit current of about 4 microamps or higher. If the current is high but the performance is poor, look for dirt or dust on or down the tube, or unwanted discharges to sharp corners or points. If the current is poor, it is usually that the belt requires replacement or the belt is dirty or the motor driving pulley is coated in foreign matter and needs cleaning.
5. Retention of charge after machine is switched off.
6. Difference between discharge to a ball and discharge to a point.
7. After switching off, note charge on belt surface. Touch with the finger.
8. In darkened room, see leakage paths, discharges to dust in the air, brush discharge from upper 'comb', different shapes of sparks, effect of bringing different objects close to the dome when at a high potential.
9. Note the behaviour of a scrap of paper dropped between the balls.
10. Reduce the power (torque) of the motor and observe the belt slow down as the charge on the dome increases. Work is done to transport charge on the belt from a place of low potential (housing) to a place of high potential (upper dome).
Designed and manufactured in Australia by Industrial Equipment and Control Pty Ltd
Distributed by
Scientrific Pty Ltd
ABN 55 056 072 694
P O Box 420 Yamba NSW 2464
Phone (02) 6645 8111 Fax (02)66458125