Automatic damping and transient supressing improvement in synchronous motors and generators
OwnerLouis Maininventor
Life of this patent
Estimating the term…
Abstract
A synchronous motor/generator is modified by mounting the conventional rotor on a sleeve that rotates freely on the main shaft rather than being fixedly mounted on the shaft. Limits to this rotation are incorporated in the design such that the maximum angular rotation of the rotor on the shaft equals half the stator advance that occurs during a complete full cycle of the AC stator winding voltage. In addition to smoothing transients, this configuration permits the machine to smoothly drop into the correct stator/rotor flux phase when it changes from a motor to a generator, and back into the correct phase for a motor, when the AC power is interrupted, and subsequently resumes, resulting in dropping a single cycle.
Claims15
A synchronous electrical machine defining a rotational axis and having a stator, a shaft member coaxially rotatably mounted within said stator and having a rotor member mounted thereon, and field windings on said rotor member, one of said members being a driving member and the other of said members being a driven member comprising:
- (a) means between said rotor member and said shaft member for coupling said rotor member and said shaft member and providing a degree of coaxial rotational freedom between said members whereby one of said members is rotatable with respect to the other member of said members between rotational limits;
- (b) limit means incorporated into said machine for defining rotational limits to said coaxial rotational freedom;
- (c) limit switch means operative with said limit means for energizing or de-energizing an external circuit upon a respective limit being reached, to control the source of power to an external load.
A self-adjusting synchronous electrical machine comprising:
- (a) a stator defining a rotational axis and being wound with stator windings;
- (b) a rotor member having field windings thereon and being coaxially rotatably mounted within said stator;
- (c) a shaft member being coupled in axially aligned driving relationship with said rotor member;
- (d) means between said rotor member and said shaft member for coupling said rotor member to said shaft member and providing a degree of coaxial rotational freedom between said members wherein said members are rotatable with resect to each other;
- (e) limit means on said means between said rotor member and said shaft member for coupling said rotor member to said shaft member for defining limits to said coaxial rotational freedom;
- and
- (f) limit switch means coupled to said limit means for energizing or de-energizing an external circuit upon a limit being reached to control the source of power to an external load.
A method of attenuating transients between stator and rotor magnetic fields in a synchronous motor having a stator with stator windings and rotor with rotor windings, and a rotary shaft, comprising:
- (a) providing a sleeve which is close-fitting on said shaft for rotational motion about the axis thereof;
- (b) mounting said rotor with the rotor windings thereon, on said sleeve such that both rotor and sleeve are rotatable about the axis of said shaft;
- (c) coupling said rotor to said shaft;
- (d) permitting said rotor to rotate relative to said shaft within limits;
- (e) defining stops to limit the rotational motion of said sleeve with respect to said shaft to a predetermined angle;
- and
- (f) providing a limit switching means on said rotor and on said shaft and using said limit switching means to control power to an external circuit.
Dependencies are inferred from the claim text.