US PATENT SUBCLASS 318 / 521
FIELD OR SECONDARY CIRCUIT CONTROL

Current as of: June, 1999
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318 /   HD   ELECTRICITY: MOTIVE POWER SYSTEMS

521FIELD OR SECONDARY CIRCUIT CONTROL {6}
523  DF  .~> Plural, diverse or diversely connected or controlled field windings {6}
530  DF  .~> Plural, diverse or diversely connected or controlled sources of field circuit voltage
531  DF  .~> Variable length or tapped field winding
532  DF  .~> By means of space-discharge device in field circuit
533  DF  .~> Impedance-controlled {1}
536  DF  .~> By field circuit making and/or breaking {1}

DEFINITION

Classification: 318/521

(under the class definition) Subject matter in which means are provided for controlling (1) the electric circuit which is connected to the magnetic-flux producing means of the motor, or (2) the electric circuit which is connected to the secondary (i.e., induced) member of an alternating current motor.

SEE OR SEARCH THIS CLASS, SUBCLASS:

81, for plural motor systems having means for controlling the speed of one or more electric motors relative to the speed of one or more other electric motors by controlling the field or secondary circuit of one or more of the motors.

84, for plural motor systems having means for controlling the speed of two or more electric motors by controlling the field or secondary circuits of the motors.

89, for braking systems in plural motor systems in which one or more of the motors are converted into exciters for supplying field excitation to the remaining motors during the braking period.

97, for plural motor systems having means for controlling the field or secondary circuit of one or more electric motors for controlling the acceleration of two or more motors.

100, for plural motor systems having field or secondary circuit control of the motors to effect a fixed or predetermined ratio of load or current division between the motors. 153, for generator-fed motor systems having combined control of generator field circuit and of the field circuit of the motor supplied by the generator.

190, and the subclasses specified in the Notes to the definition of those subclasses for synchronous motor systems in which means are provided for controlling the field circuit of the motor.

232, for induction motor systems having secondary circuit control of the motor.

246, for motor systems in which the motor is connected to run as a series motor and in which substantially all circuit control affects the field excitation.

296, for this subject matter in motor reversing systems.

381, for dynamic braking motor systems in which there is field circuit control when the armature circuit is locally closed (e.g., short circuited).

493, and the subclasses specified in the Notes thereto, for motor systems having field circuit control combined with armature or primary circuit control.

SEE OR SEARCH CLASS

322, Electricity: Single Generator Systems,

59, for field circuit control of electric generators.

388, Electricity: Motor Control Systems, 801+, and 826+ for single motor running-speed control systems; and subclasses 843 and 849+ for single motor acceleration control systems; wherein the energization of a field winding, or of both a field winding and an armature winding, is controlled.