Resources Contact Us Home
Coordinated load commutated inverter protection system

Image Number 19 for United States Patent #4475150.

A fault protective system for a load commutated inverter motor drive including an AC to DC source side converter coupled from an AC source to a DC to AC load side converter via a DC link circuit and wherein the load side converter supplies AC power of varying magnitude and frequency to the synchronous motor load. A pair of microcomputers interlinked by a common digital memory respectively control the inverters and interface with hardware type sensor means for detecting the occurrence of a plurality of different types of faults. Additionally, a number of stored instructional sets or programs are respectively included in both microcomputers to detect by software means another plurality of faults. The detection of a fault on either side of the link circuit is communicated to the respective computer which subsequently communicates with the other microcomputer to effect a coordinated protective action in response to thyristor cell failures, circuit failures, and abnormal operating conditions. Cell failure faluts include those instances where a thyristor cell actually fails due to an open or short circuit as well as those cases where a cell fails to commutate properly due to firing strategy problems. Cirucit failures include open and short circuits both in the supply line and the motor leads, while abnormal operating conditions involve such things as low line voltage or excessive motor voltage.

  Recently Added Patents
Preparation and its use of derivatization reagent for detecting L-carnitine or D-carnitine
Method and composition for improving skin barrier function
Method for producing cathode active material for a lithium secondary battery
Electric discharge machining hole drilling
High gradient lens for charged particle beam
Method and apparatus for web crawling
  Randomly Featured Patents
Latex for high performance masking tape
Superhard film-coated member and method of manufacturing the same
Printer for printing visually equivalent images relative to displayed images
Sequential circuit for high frequency clocking
Capacitive analog to digital converter
Fiber intensity reducing devices and related systems
Hat with retractable accessory attachments
Synchronization device for output stages, particularly for electronic memories
Replaceable faceplates for peripheral devices
Off-track retry method in hard disk drive