Low power refrigerating machine for cooling a power cabinet or an electronic or electromechanical device, which comprises: - a cooling circuit comprising a compressor; - an electric motor connected to said compressor in order to operate it; - an operating apparatus connected to said electric motor in order to power wherein said operating apparatus comprises: - an AC/DC converter device configured so that it may be connected, by means of a first input connector, to a single-phase or three-phase or DC electrical network and so as to provide a first output connector with an output voltage (Vu); - a DC/AC converter device connected to said first output connector so as to be powered by the latter at said output voltage (Vu) and having a second output connector connected directly to said electric motor in order to power it; said DC/AC converter device being configured to power said electric motor with a power supply voltage (Va) and at a power supply frequency which are variable upon command and independent of the power supply provided by said electrical network; - a control device connected to said AC/DC converter device and to said DC/AC converter device; - at least one fan (23a, 23b) connected to said control device so as be operated at a variable speed; said cooling circuit comprising at least one heat exchanger to which said at least one fan (23a, 23b) is connected; - characterized in that the refrigerating machine further comprises a flyback power supply connected to: - said first output connector, in order to be powered; - said at least one fan (23a, 23b), in order to regulate the speed of rotation thereof; - said control device in order to be operated so as to regulate the speed of rotation of said at least one fan (23a, 23b) depending on the operating conditions of said cooling circuit; and wherein said at least one fan (23a, 23b) is configured to be powered by a DC current and the flyback power supply comprises a PWM control system for powering the at least one fan (23a, 23b) in order to regulate the operating speed thereof. - a cooling circuit comprising a compressor; - an electric motor connected to said compressor in order to operate it; - an operating apparatus connected to said electric motor in order to power wherein - an AC/DC converter device configured so that it may be connected, by means of a first input connector, to a single-phase or three-phase or DC electrical network and so as to provide a first output connector with an output voltage (Vu); - a DC/AC converter device connected to said first output connector so as to be powered by the latter at said output voltage (Vu) and having a second output connector connected directly to said electric motor in order to power it; said DC/AC converter device being configured to power said electric motor with a power supply voltage (Va) and at a power supply frequency which are variable upon command and independent of the power supply provided by said electrical network; - a control device connected to said AC/DC converter device and to said DC/AC converter device; - at least one fan (23a, 23b) connected to said control device so as be operated at a variable speed; said cooling circuit comprising at least one heat exchanger to which said at least one fan (23a, 23b) is connected; - characterized in that the refrigerating machine further comprises a flyback power supply connected to: - said first output connector, in order to be powered; - said at least one fan (23a, 23b), in order to regulate the speed of rotation thereof; - said control device in order to be operated so as to regulate the speed of rotation of said at least one fan (23a, 23b) depending on the operating conditions of said cooling circuit; and wherein said at least one fan (23a, 23b) is configured to be powered by a DC current and the flyback power supply comprises a PWM control system for powering the at least one fan (23a, 23b) in order to regulate the operating speed thereof.