Method for heating a fluid circuit by supplying alternating current to a direct-current pump motor

A heating device intended to heat a body, such as a fluid contained in a fluid circuit, said heating device comprising:

• at least one electric heating element;
• and
• at least one control module comprising an electronic circuit arranged to electrically power said heating element so that said heating element produces heat to heat the body,
• wherein said heating element is formed by a propulsive winding circuit of a direct-current electric motor which, when it is electrically powered by an appropriate direct supply voltage (Usupply), having a given polarity, generates a drive force which tends to drive the motor in a direction of displacement which is determined by the polarity of said supply voltage (Usupply), and
• wherein the control module comprises an activation mode, which is referred to as a heating oscillating mode, according to which said control module causes the warm-up of the propulsive winding circuit by applying at the terminals of said winding circuit an alternating supply voltage (Usupply) whose polarity switches, alternately and automatically, according to a predetermined frequency, which is referred to as a heating frequency (FH), from a first polarity to an opposite second polarity.