Abstract: A stator adapted for mounting adjacent the periphery of a moving machine gear, whereby the gear serves as a rotor in an electric alternator. A pair of elongated pole pieces are mounted in parallel adjacent the gear periphery. Dependent teeth are formed on each of the ends of each pole piece. The ends of the teeth of the pole pieces are separated from the gear tooth tips by a short air gap. The pole pieces are of length such that when the teeth at one end of a pole piece overlie gear tooth tips, the teeth at the opposite end of that pole piece overlie spaces between gear teeth. The pole pieces are displaced longitudinally relative to one another so that when the teeth at one end of one pole piece overlie gear tooth tips, the teeth at the like end of the other pole piece overlie spaces between gear teeth. Magnets are positioned between the pole pieces, one at each end. Gear motion induces electrical potentials in conductor coils wound on the pole pieces.

Abstract: A speed sensor (30) for an electromagnetic machine (31) such as a permanent magnet generator includes a magnetic core (44) mounted laterally outboard of the machine's stator teeth (36) and having at least one leg (48) adjacent openings (43) in slots (38) between the stator teeth (36) which extends into the alternating magnetic flux field (42) generated by the machine's rotor (34) in order to pick up a sample (42) of the rotor flux. A portion (50) of the core (44) has wrapped therearound an electrical coil (52) within which there is induced by the flux sample (42) an alternating electrical signal having a frequency proportional to the angular velocity of the rotor (34). The magnetic core (44) may consist of either one or more discrete U-shaped members (44) each having legs (46,48) immediately adjacent or extending into the slots (38) of the stator (32) or a continuous strip (44f,44g) of material extending circumferentially around the stator (32) and having a plurality of the legs (48).