Electrostatic coating system, spray gun for electrostatic coating, and alternating power source unit

An electrostatic coating system which includes an electrostatic coating spray gun atomizing an electrically charged coating material and applying the atomized coating material to an object to be coated and an alternating-current (AC) power supply generating alternating voltage,

• the electrostatic coating spray gun comprising:
• a gun body made of a non-conductive material;
• a voltage generation unit generating a direct-current (DC) voltage based on AC voltage supplied thereto via an AC voltage supply line from the AC power supply;
• an electrode to which the DC voltage generated by the voltage generating unit is applied for charging the coating material to be atomized;
• and
• a grounding member detachably attached to the gun body and provided so as to be spaced from the electrode when attached to the gun body, the grounding member having a conductive property such that the grounding member generates an electric field between the electrode to which the DC voltage is applied and the grounding member,
• the AC power supply comprising:
• a detection unit which detects a current flowing via the AC voltage supply line or voltage of the AC voltage supply line;
• and
• a control unit which controls supply of the AC voltage via the AC voltage supply line to the voltage generation unit, based on the detected current or detected voltage,
• wherein the AC voltage supply line includes a ground side supply line which is grounded, the ground side supply line including a part formed with an open circuit;
• wherein the grounding member is configured to close the open circuit when attached to the gun body;
• and
• wherein the control unit is configured to stop supply of the AC voltage to the voltage generation unit when the detected current or the detected voltage is reduced while supplying the AC voltage to the voltage generation unit or when the current or the voltage is not detected.