Patents Examined by S. C. Medley
  • Patent number: 5402299
    Abstract: An arrangement to coordinate protective devices is provided by defining operation of the instantaneous characteristic portion of an upstream protective device to coordinate with a downstream current-limiting fuse based on the peak let-through current of the downstream current-limiting device, with instantaneous operation being set to occur only above the peak let-through current of the downstream current-limiting fuse. Accordingly, for fault currents which are seen by both the instantaneous device and the current-limiting device and that are within the ratings of the current-limiting device, the upstream device will not respond and the downstream current-limiting fuse will interrupt the fault, as intended.
    Type: Grant
    Filed: September 18, 1992
    Date of Patent: March 28, 1995
    Assignee: S&C Electric Company
    Inventor: Terrance A. Bellei