摘要 |
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).
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