Westinghouse Electric Corporation

Lee A Kilgore

Stephen B Kuznetsov

William H South

Bobby D McKee

Dale I Gorden

Gurney L Godwin

Eugene C Whitney

Arthur H Hoffmann

Edgar R Taylor, Jr

A homopolar dynamoelectric machine is provided with current collecting structures which produce a peripheral, circumferential component of load current for self-excitation. The current collection structures include brush boxes which are skewed at a first angle with respect to the rotor axis and a generally cylindrical stator conductor having slits which are skewed at a second angle with respect to the rotor axis. Current flowing in the brushes and stator conductor is forced to have a circumferential component which compensates for rotor saturation due to load current and minimizes the voltage droop characteristic of drum-type homopolar generators.

Homopolar dynamoelectric machine with self-compensating current collector

A drum type homopolar dynamoelectric machine includes a rotor, a main field coil and an auxiliary field coil. The field coils encircle different portions of the rotor and are supported by a stator structure having a main pole piece for directing magnetic flux produced by current flowing in the main field coil radially into a section of the rotor. A current transfer assembly makes sliding electrical contact with a current collecting zone on the surface of the rotor which is axially positioned between the main and auxiliary field coils. Current flowing in the auxiliary field coil tends to reduce the amount of leakage flux in the current collecting zone produced by current flowing in the main field coil. This reduces undesirable circulating currents in the rotor current collecting zone and the associated current collecting structures.

Homopolar dynamoelectric machine with an auxiliary field coil

A drum-type homopolar dynamoelectric machine includes a rotor and an annular field coil encircling a portion of the rotor. The field coil is supported by a stator structure having a main pole piece for directing magnetic flux produced by current flowing in the coil, radially into a section of the rotor. A current transfer assembly makes sliding electrical contact with a current collecting zone on the surface of the rotor and is axially positioned between the main pole piece and an end pole piece of the stator which directs magnetic flux axially out of the end of the rotor. A magnetic flux shield is positioned adjacent to the field coil to minimize leakage flux, caused by current flowing in the field coil, in the vicinity of the current collecting zone of the rotor. This reduces undesirable circulating currents in the rotor current collecting zone and the associated current collecting brushes.

Homopolar dynamoelectric machine with a shielded stator excitation coil

A marine propulson system is described that includes a gas turbine, an alternating current generator, a fixed pitch propeller, a synchronous motor and a frequency converter. The frequency converted is connected electrically between the generator and motor during starting and reversal procedures when the motor would normally have to operate as an induction motor. Means are provided to brake the system dynamically to speeds within the capacity of the frequency converter. At speeds within the frequency converter's design capacity, the motor can be operated synchronously while it is running at a speed below the minimum operating speed of the turbine and generator.

Marine propulsion system

Method and apparatus for accelerating a large inertia load from rest to a predetermined speed of rotation by means of a synchronous dynamoelectric machine. A synchronous dynamoelectric machine, such as a turbine generator, which is mechanically coupled to a gas turbine prime mover, is started synchronously to bring the gas turbine up to a speed which exceeds its stall speed under load. The rotor field winding of the synchronous dynamoelectric machine is connected to receive direct current excitation from a rotatable rectifier assembly of a brushless exciter. During starting, a quadrature axis winding disposed around the stator of the brushless exciter is energized by single phase alternating current. Alternating current excitation is induced by transformer action within the rotor armature winding of the exciter and is applied to the rotor field winding after being rectified by the rotatable rectifier assembly. The transformer action operates independently of the rotation of the rotor member of the synchronous dynamoelectric machine so that the brushless exciter develops direct current field excitation for starting purposes when the rotor is at rest. Polyphase alternating current excitation is applied to the synchronous dynamoelectric machine stator winding to establish a dynamic magnetic field which rotates at a speed proportional to the frequency of the applied excitation. Interaction of the static magnetic field of the rotor and the rotating stator field produces the mechanical turning force. The frequency of the synchronously applied stator excitation is increased from substantially zero cycles per second to a higher frequency until the rotor member has accelerated synchronously to the desired speed of rotation.

Quadrature axis field brushless exciter

An analog simulator for simulating the mechanical resilience, mass and damping characteristics of a turbine-generator system. The aforementioned parameters are represented by inductance, capacitance and resistance in the simulating system. Electrical power at the output of a generator is sensed by a power transducer and is provided as input to the simulating system. The power is a measure of the torque on the shaft of the generator. The simulating system computes the torsional oscillations between rotating members of the turbine-generator system and provides electrical output signals which are related to the magnitudes and frequencies of the various computed torsional oscillations. The signals are provided to indicating means such as counters, strip recorders and oscillographs for recording the timing, magnitude, and frequency of the various torsional oscillations. The signals are also provided to shut-down means so that the turbine-generator may be shut down if the torsional oscillations are of sufficient magnitude to damage the system shaft.

Supervisory system for detecting torsional oscillation in the shaft of a

A dynamic stabilizer which includes a voltage generator connected in series with the output terminals of a synchronous AC generator provides compensation for voltages produced by the main AC synchronous machine which compensation is provided to overcome the effects of torsional oscillation between masses in the main AC generator system. Torsional oscillations may exist between the masses of turbines driving the AC generator, the exciter mass for the AC generator, and the mass of the rotor of the generator. Shaft angular velocity is sensed and provided to a frequency discriminating filter since the speed is proportional to the torsional oscillation and since a reference signal is provided to the frequency discriminating filter, the frequency discriminating filter provides an output signal which is proportional to the reference signal plus and minus the frequency of the torsional oscillation. This signal is provided to the previously named series connected generator where a 180.degree. phase shift is effectuated between the output signal of the frequency discriminating filter and the output power from the AC synchronous generator. Scaling means is provided to conveniently match the peak amplitudes of the last named signals. The effect of the phase shift of the signal from the frequency discriminating filter as it is applied to the series connected generator is to compensate for the effect of the torsional oscillations in the output power signal of the AC synchronous generator thus providing a power signal for use in a load which is generally without modulating torsional oscillation.

Dynamic stabilizer for synchronous machines having torsional

Two cascaded induction machines provide asynchronous power transmission between two independent generating networks. The shafts of the two induction machines are mechanically connected for concurrent rotation and the rotor windings of the two machines are electrically connected in a reverse phase sequence. The cascaded induction machines are geared to a relatively low power variable speed drive which accurately controls the position and rotation of the shafts. A control system supplies low frequency excitation current for the variable speed drive and is capable of continuous operation through zero frequency to reverse the direction of rotation. The control system determines the level of power flow within the induction machines and is unresponsive to the difference in frequency of generation of the two generating networks so that the power flow is controlled even under transient load conditions.

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Export, PA, United States of America

Lee A Kilgore