An electrostatic spray gun having a rotatable voltage generator for providing electrical energy at low voltage for conversion within the spray gun into electrostatic high voltage energy, wherein a rotating voltage generator is driven by an air turbine under the influence of a pressurized input air supply, the pressurized air passing through conduits in the handle of the spray gun, an air valve actuated by a trigger, an air flow regulator, and into impinging contact against rotatable turbine blades. The air supply is exhausted from the spray gun through internal passages which provide cooling air to the electrical components within the spray gun, and through further passages opening from the bottom of the spray gun handle which minimize the audible noise caused by such air flow.

A pneumatic system is disclosed for regulating the acceleration and running speed of an air turbine and alternator used in electrostatic spray apparatus having a self-contained electrical power supply. The air turbine includes a rotor which is arranged to be biased in a first direction of rotation by a flow of impinging drive air and in a second opposite direction by a flow of impinging brake air. The flows of air cooperatively result in rotation of the turbine in a desired direction of operation and enable a minimized period of acceleration for a predetermined running speed.

An electrostatic spray gun for the application of paints and other coatings has a high voltage power supply having a contact at the front end thereof. A flange on the end of the power supply surrounds the contact and a rubber boot seal snaps over the flange. Located within the rubber boot is a conductive rubber pin which contacts with a conductor located in the barrel of the gun. Utilization of this design minimizes capacitance in the front end of the gun and also virtually eliminates air volume in the area which in turn limits the production of harmful ozone.

An air amplifying blow-off system incorporating an ionizing apparatus includes a converter driven by the compressed air being directed to an air distributor. The converter provides the power source for the ionizing apparatus. In this way, the air distributor and ionizing apparatus can be an easily contained unit. The system may comprise a turbine which is electrically connected to an ionizing apparatus, such as an ionizing bar. Another system may comprise an oscillatory device connected to a pair of opposing electrodes through a piezoelectric device. The compressed air drives the oscillatory device. The piezoelectric device provides a pulsating supply of voltage to the ionizing device. This invention allows the blow-off/ionizer system to be utilized in potentially explosive environments. Further, the efficiency of the systems is increased since power losses across the relatively long cables incorporated in the prior art systems is eliminated.

An electrostatic spray gun is provided with a spraying voltage control. The contol is produced by Hall effect or magnetoresistive circuitry incorporated with the circuitry of the spray gun. A variably positionable magnet is provided so that the operator may selectively adjust the spraying voltage by positioning the magnet relative to the Hall effect circuitry.