ELECTRICAL APPARATUS WITH FREQUENCY CONTROLLED LOAD COMPENSATION

• US 3,667,012 A
• Filed: 07/31/1970
• Issued: 05/30/1972
• Est. Priority Date: 07/31/1970
• Status: Expired due to Term

• Current Assignee: Lee A. Kilgore
• Original Assignee: Lee A. Kilgore
• Inventors: Kilgore, Lee A.
• Primary Examiner(s): Rubinson, Gene Z.
• Application Number:
  US05/059,949
• Time in Patent Office: 669 Days
• Field of Search: 318/161,197,227,237,150
• US Class Current: 318/161
• CPC Class Codes: H02J 3/30 using dynamo-electric machines coupled to flywheels
• CPC Class Codes: H02P 27/04 using variable-frequency supply voltage, e.g. inverter or converter supply voltage
• CPC Class Codes: H02P 27/05 using AC supply for both the rotor and the stator circuits, the frequency of supply to at least one circuit being variable
• CPC Class Codes: Y02E 60/16 Mechanical energy storage, e.g. flywheels or pressurised fluids

Abstract

A wound rotor motor and a flywheel are provided on a shaft with speed control of the motor by frequency control on its secondary applied by means such as a cycloconverter that is responsive to pulsating load conditions on the system. Power flows from the flywheel into the system during periods of high load and into the flywheel during periods of low motoring load or a regenerative load. The invention permits use of equipment, such as large excavators, that have sharply varying loads in their duty cycles, in locations where there are small, otherwise inadequate, power systems.

Claims

1. In combination:

an induction dynamoelectric machine with a stator and a rotor and windings on each of said stator and said rotor;

a mechanical energy storage device mechanically connected with said rotor;

a cycloconverter electrically connected with selected ones of said windings to control speed of rotation of said rotor and electrical-mechanical energy transfer between said energy storage device and said windings on said stator.

2. The subject matter of claim 1 further comprising:

an alternating current power system connected with said stator windings and with an electrical load that normally pulsates over its duty cycle, said dynamoelectric machine transferring energy between said mechanical energy storage device and said power system to maintain actual power demand on said system within limits that are narrow compared with the load pulsations.

3. The subject matter of claim 2 wherein:

said pulsating load duty cycle has both motoring and regenerative load portions;

said mechanical energy storage device is a flywheel; and

said cycloconverter comprises solid state switching elements and has independent frequency and current amplitude control units associated therewith.

4. The subject matter of claim 2 wherein:

a frequency control unit is associated with said cycloconverter to regulate the frequency applied to said motor windings in accordance with power developed by said power system and with the speed of said rotor.