An atomizer (P 1) for electrostatically spraying coating material in liquid or in powder form, said atomizer comprising: - an electrically insulating body; - an atomizer member for spraying coating material, which member is mounted to rotate relative to the body and about an axis of rotation (X 2); - rotary drive means for driving the atomizer member in rotation; - electrical power supply means arranged for raising the potential of the atomizer member to high voltage; - conductive elements (2, 1, 6, 8, 9, 22, 23, 33) that are electrically connected to the electrical power supply means and that belong, in particular, to the atomizer member, to the rotary drive means, and to the electrical power supply means, the potential of the conductive elements (2.1, 4, 6, 8, 9, 22, 23, 33) being suitable for being raised to high voltage; and - a detector device for evaluating the speed of rotation of the atomizer member, the detector device comprising: - at least one target (41, 42) disposed on a rotary component belonging to the atomizer (P1; P2), such as the atomizer member or one of the rotary drive means; and - a sensor fastened in the atomizer (P1; P2), the sensor being configured to detect the or each target (41, 42), the sensor being equipped with a link cable for linking it to a remote processor unit for processing the signal; said atomizer (P 1) being characterized in that it further comprises at least one wall (50; 150) made of an insulating material and which is formed integrally with the body, the wall (50; 150) defining a recess (51; 151) surrounding the sensor and all or some part of the link cable in a manner such as to insulate the entire sensor and all or some part of the cable link electrically from the conductive elements (2.1, 6, 7, 8, 9, 22, 23). - an electrically insulating body; - an atomizer member for spraying coating material, which member is mounted to rotate relative to the body and about an axis of rotation (X 2); - rotary drive means for driving the atomizer member in rotation; - electrical power supply means arranged for raising the potential of the atomizer member to high voltage; - conductive elements (2, 1, 6, 8, 9, 22, 23, 33) that are electrically connected to the electrical power supply means and that belong, in particular, to the atomizer member, to the rotary drive means, and to the electrical power supply means, the potential of the conductive elements (2.1, 4, 6, 8, 9, 22, 23, 33) being suitable for being raised to high voltage; and - a detector device for evaluating the speed of rotation of the atomizer member, the detector device comprising: - at least one target (41, 42) disposed on a rotary component belonging to the atomizer (P1; P2), such as the atomizer member or one of the rotary drive means; and - a sensor fastened in the atomizer (P1; P2), the sensor being configured to detect the or each target (41, 42), the sensor being equipped with a link cable for linking it to a remote processor unit for processing the signal; said atomizer (P 1) being characterized in that it further comprises at least one wall (50; 150) made of an insulating material and which is formed integrally with the body, the wall (50; 150) defining a recess (51; 151) surrounding the sensor and all or some part of the link cable in a manner such as to insulate the entire sensor and all or some part of the cable link electrically from the conductive elements (2.1, 6, 7, 8, 9, 22, 23).