A current detection resistor is connected between an output terminal of a high voltage generator and an air motor. A coater current detector detects a coater current supplied to a coater based on a potential difference taking place on both terminals of the current detection resistor. The high-voltage control device serves to discriminate based on the coater current detected by the coater current detector whether the coater is caused to be close to a coating object. When it is discriminated that the coater is caused to be close to the coating object, the high-voltage control device outputs a shut-off signal for shutting off supply of the power supply voltage to the power supply voltage control device.

An alternator, such as for use in an electrostatic spray gun, comprises an electromagnetic alternator, a housing and an impeller. The electromagnetic alternator has a shaft. The electromagnetic alternator is disposed within the housing. The housing has an air aperture. The impeller is mounted to the shaft within the housing so as to be aligned with the air aperture. The impeller includes blades having curved leading and trailing edges. In one embodiment, each blade has a curvature so as to be perpendicular to the air aperture across an entire arc over which each impeller blade has a line of sight of the air aperture.

An electrostatic coating apparatus includes a coating gun that sprays a coating material toward a coated matter, a high-voltage application apparatus that applies a high voltage to the coating gun, a bell-side current calculation unit that calculates a bell-side current to flow from the coating gun to the coated matter, an earth-side current measurement unit that measures an earth-side current to flow from the coated matter to the earth, and an earth check unit that detects an abnormal earth state of the coated matter, depending on a magnitude relation between the bell-side current calculated at the time of electrostatic coating and the bell-side current when the earth is properly connected, and a magnitude relation between the earth-side current measured at the time of the electrostatic coating and the earth-side current when the earth is properly connected.

A system includes an electrostatic tool having a cascade that includes electrical components configured to convert a first voltage from an incoming alternating current into an outgoing second voltage at a direct current and a shell configured to cover the electrical components. The shell radially conforms to the electrical components.

In one embodiment, systems and methods include an electrospray device for atomizing fluids comprising a body defining a resonant microwave cavity, wherein the body comprises a radio frequency inlet configured to inject a radio frequency signal received from a power source into the resonant microwave cavity, wherein the resonant microwave cavity is configured to to amplify a voltage of the radio frequency signal. The device further comprises a field concentrating pole disposed within the resonant microwave cavity configured to concentrate the amplified voltage at a first end of the field concentrating pole to form an electric field. The device further comprises a nozzle disposed at the first end of the field concentrating pole and a fluid supply line configured to provide a fluid disposed within the field concentrating pole and fluidly connected to the nozzle, wherein the fluid supply line is fluidly connected to a fluid source.

An aerosol-generating device includes: a housing having a liquid storage cavity for accommodating an aerosol-generating substrate; a metal element arranged outside the liquid storage cavity; a static electricity generating assembly including a positive terminal and a negative terminal, one of the positive terminal and the negative terminal being electrically connected to the metal element so as to cause a part of the aerosol-generating substrate that is close to the metal element in the liquid storage cavity to be charged by electrostatic induction when the static electricity generating assembly is electrified; and a vaporization sheet, that, when electrified, vaporizes the charged aerosol-generating substrate to generate a charged aerosol.