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US 4,939,441 AGranted
Excitation system for a brushless generator having separate AC and DC exciter field windings
AssigneeSundstrand Corporation
InventorP. John Dhyanchand
Life of this patent
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AssigneeSundstrand Corporation
InventorP. John Dhyanchand
Estimating the term…
An excitation system for a brushless generator includes an exciter portion having a set of polyphase exciter field windings and an additional exciter field winding disposed in a stator of the generator, a source of polyphase, constant-frequency AC power and circuitry coupled to the set of polyphase field winding for connecting the source of polyphase, constant-frequency AC power thereto at a beginning of operation in a starting mode whereby AC power is induced in an exciter portion armature winding by transformer action. AC power is further provided to armature windings of a main generator portion to thereby cause a rotor of the generator to accelerate. An autotransformer is provided to reduce the voltage provided by the source of polyphase AC power prior to application of such power to the polyphase field windings so that the need for an auxiliary inverter is obviated. Thereafter, at least one of the windings of the set of polyphase windings is connected in series with the additional field winding when the speed of the rotor reaches a predetermined speed and a DC current of controlled magnitude is delivered to the series-connected exciter field windings to thereafter allow operation in a generating mode.
An excitation system for a brushless generator having a main generator portion including a field winding disposed on a rotor and which receives field current and an armature winding disposed in a stator wherein the rotor is movable with respect to the stator and the generator is operable in a generating mode to convert motive power into electrical power which is developed in the armature winding and in a starting mode to convert electrical power provided to the armature winding into motive power, comprising:
An excitation system for a brushless generator having a main generator portion including a field winding disposed on a rotor and which receives field current and an armature winding disposed in a stator wherein the rotor is movable with respect to the stator and the generator is operable in a generating mode to convert motive power into electrical power which is developed in the armature winding and in a starting mode to convert electrical power provided to the armature winding into motive power, comprising:
An improvement in a brushless generator having a main generator portion including a field winding disposed on a rotor and an armature winding disposed in a stator wherein the rotor is movable with respect to the stator and further including an exciter portion having polyphase AC field windings and a DC field winding disposed in the stator and a set of exciter armature windings diposed on the rotor, the generator being operable in a generating mode to convert motive power into AC electrical power at a certain frequency and voltage which is developed in the main generator portion armature winding and in a starting mode to convert electrical power provided to the main generator portion armature winding into motive power, the exciter portion AC field windings receiving power developed by an AC power source at the certain frequency and voltage at a beginning of operation in the starting mode and thereafter the DC field winding receiving a controlled magnitude of DC current, the improvement comprising:
Dependencies are inferred from the claim text.