The electrostatic atomizers - guns, rotating bell units, blades, etc. - their High Voltage cables and the connected generators have altogether a more or less high electrical capacity.

When electrically charged they store an energy equal to ½ CV² where C is the capacity of the system and V the applied voltage.

When the generator is switched off this energy is dissipated in the surrounding air during a time T changing from few seconds to many minutes.

The time T is influenced by the insulation properties of the system, by the electrodes shape and by the umidity and temperature of the surrounding atmosphere.

The CENELEC EN 50176 European Standard concerning the automatic electrostatic painting equipment claims that any part under high voltage should be discharged within two seconds down to a discharge energy level lower than 350 mJ before letting personnel enter inside the enclosure.

To get a similar effect in the safest way we have designed and patented the ELETTROSPRAY^® Earthing Switch here described which satisfies the prescription of the Standard above as proven by TÜV Test Report No. SIC02067.00.

The Earthing Switch should be fitted in the High Voltage circuit after the cascade.

When one of the doors of the enclosure is opened the Switch is actuated discharging to the earth through a suitable resistor the whole HV circuit.

All the energy stored in the system is in this way quickly dissipated and once the doors are opened the operators can touch the bells, the electrodes or the blades in full safety without fear of any electrical shock.

The HV circuit stays safely connected to the earth till the doors are closed again. It is therefore impossible to switch on again the HV while the doors are open.

The ELETTROSPRAY^® Earthing Switch is driven by a single effect pneumatic cylinder: should the compressed air fail the circuit will be earthed while to restore the HV the air pressure must be over the min value requested by the machine.

The ELETTROSPRAY^® Earthing Switch is built for 150 kV max electrostatic voltage with 1mA max current.

It is supplied complete with a 1 m long HV cable ready to be connected to the HV cascade.

A typical application is on board the electrostatic oilers where one unit is normally required for each blade.