Abstract: Each arm forming a three-phase full wave rectifier bridge includes a semiconductor diode, a current transformer and a fuse. The current transformer is connected to a pulse extinction indicator circuit through a pulse transformer. When no current flows through the arm for a predetermined time or more, the pulse extinction detection circuit produces a DC signal indicating the blowing of the fuse. The rectifier bridge, the current transformers, the fuses and the pulse extinction detection circuit are all disposed on the rotor of a brushless synchronous machine.

Abstract: The rotor of an electric rotary machine is provided with two identical transmitting devices each including an amplitude modulator and a transmitting antenna. One of the modulators modulates a carrier with clock pulses while the other modulator modulates the same carrier with a data signal from the rotor expressed by a binary digital code including pulses identical in both shape and phase to the clock pulses. The transmitting antennas are disposed symmetrically with respect to a receiving antenna located externally of the rotor to induce the two modulated carriers substantially in phase across the receiving antenna.