Rotor/stator voltage modulation device, in particular for a brushless electric motor

A device for modulating a voltage supplied to a motor, said device comprising:

• a fixed stator having a first statoric portion and a second statoric portion;
• a DC voltage source having positive and negative terminals;
• at least one annular resistive signal track located on said first statoric portion of said fixed stator and centered on a fixed central axis Z--Z, said at least one annular resistive signal track having an even plurality of angularly distributed connection points, said even plurality of angularly distributed connection points being alternately connected with said positive and said negative terminals of said DC voltage source, so that said at least one annular resistive signal track has an electrical potential having a periodic circumferential variation between a maximum value and a minimum value;
• at least two collector tracks located on said second statoric portion of said fixed stator and concentrically centered on said fixed central axis Z--Z,
• at least two output terminals carried by said fixed stator, each output terminal of said at least two output terminals being electrically connected to a respective collector track of said at least two collector tracks;
• a rotor coaxially disposed along said fixed central axis Z--Z, said rotor having a first rotoric portion and a second rotoric portion;
• a rotary drive member mounted with said rotor for rotating said rotor about said fixed central axis Z--Z,
• at least two output brushes mounted on said first rotoric portion of said facing said second statoric portion, each said output brush of said at least two output brushes being contiguous to and in sweeping contact with a single collector track of said at least two collector tracks;
• at least two input brushes mounted on said second rotoric portion of said rotor and facing said first statoric portion, each input brush of said at least two input brushes being electrically connected to an output brush of said at least two output brushes, said at least two input brushes being contiguous and in sweeping contact with separate zones of said at least one annular resistive signal track whereby said at least two output terminals are supplied with electric signals having a potential modulated in amplitude by the rotation of said rotor.