Apparatus comprising: an induction machine requiring external excitation for generation; a permanent magnet machine configured to be mechanically driven by the induction machine via a rotatable shaft coupling the induction machine with the permanent magnet machine ; the permanent magnet machine including: a multipole rotor having a plurality of permanent magnet poles and a connector for connection to the rotatable shaft , and a stator including a winding and electrical connections, motion of the rotor with respect to the stator generating a voltage signal in accordance with a rotational speed of the shaft and a rotational direction of the shaft at the electrical connections; characterized in that the voltage signal is configured to serve both as control power for control electronics of the induction machine and as a sensing signal indicating at least one of the rotation speed and the rotational direction of the rotatable shaft ; and in that the apparatus further comprises: a circuit for receiving said voltage signal and simultaneously outputting the control power, which is effective for controlling the induction machine , and the sensing signal, said circuit including a power conversion portion for outputting the control power to the control electronics of the induction machine , and a speed sensing portion for outputting the sensing signal. an induction machine requiring external excitation for generation; a permanent magnet machine configured to be mechanically driven by the induction machine via a rotatable shaft coupling the induction machine with the permanent magnet machine ; the permanent magnet machine including: a multipole rotor having a plurality of permanent magnet poles and a connector for connection to the rotatable shaft , and a stator including a winding and electrical connections, motion of the rotor with respect to the stator generating a voltage signal in accordance with a rotational speed of the shaft and a rotational direction of the shaft at the electrical connections; a multipole rotor having a plurality of permanent magnet poles and a connector for connection to the rotatable shaft , and a stator including a winding and electrical connections, motion of the rotor with respect to the stator generating a voltage signal in accordance with a rotational speed of the shaft and a rotational direction of the shaft at the electrical connections; characterized in that the voltage signal is configured to serve both as control power for control electronics of the induction machine and as a sensing signal indicating at least one of the rotation speed and the rotational direction of the rotatable shaft ; and in that the apparatus further comprises: a circuit for receiving said voltage signal and simultaneously outputting the control power, which is effective for controlling the induction machine , and the sensing signal, said circuit including a power conversion portion for outputting the control power to the control electronics of the induction machine , and a speed sensing portion for outputting the sensing signal. a power conversion portion for outputting the control power to the control electronics of the induction machine , and a speed sensing portion for outputting the sensing signal. <EOS>