The invention relates to a synchronous permanent-magnet motor preferably used in fluid driving pumps and in particular circulators for heating and/or cooling plants, of the type comprising: a stator or stator stack housed in a circulator body; a permanent-magnet rotor; an electronic control board of the circulator, installed in a casing associated with the circulator body. Advantageously a direct internal electrical connection is provided between the stator stack 11 and the electronic board so as to form a functional earthing connection terminal. This connection is obtained by means of a terminal having one end fixed to the metal structure of the stator stack and the other end connected to said electronic board.