Power Supply for an Intrinsically Safe Circuit

Details

• Personal Author:
  Cawley, James C. ; DiMartino MD ; Fisher, Thomas J. ; King, Roger L. ; Uhler MH
• Description:
  An intrinsically safe power supply employing a binary current interrupter connected between the power source and the electrical load. Normally the load is situated in a potentially dangerous environment, like a coal mine, and the intrinsically safe power supply at a safe remote location, e.g., on the earth's surface. The interrupter has a pass and switching transistor, current sensor, gating circuitry, a flip-flop switch, and means to delay the turning on of the transistor--but not its turning off. If an overcurrent or overvoltage condition is sensed between the input and output of the intrinsically safe power supply, load current will cease to flow. In normal operation, only the current interrupter pass transistor will open. A reset signal from an oscillator internal of the interrupter may be used to reset the flip-flop after actuation or upon its initial setting, thereby causing the flow of power into the load. [Description provided by NIOSH]
• Subjects:
  Electrical Equipment And Supplies Mining Occupational Health Safety Semiconductors
• Keywords:
  Electronic Circuits Electronic Components Explosion Prevention Explosive Atmospheres Mining Industry Power Lines
• Series:
  Mining Publications
• Document Type:
  Text
• Genre:
  Other
• Place as Subject:
  OSHA Region 3 ; Pennsylvania
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  PRC - Pittsburgh Research Center
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  1-13
• NIOSHTIC Number:
  nn:10001408
• Citation:
  US Pat 4,438,473 1984 Mar; :1-13
• Federal Fiscal Year:
  1984
• Peer Reviewed:
  False
• Source Full Name:
  United States Patent 4,438,473
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:c26385bce59fd2c85fad0c91d57bc1e904d9228728e9386497fb8b55d5b0f35344b8973d8227fbf408e39fe341fa82235d01d7f577e839212bcf14161080fea8
• Download URL:
  https://stacks.cdc.gov/view/cdc/219387/cdc_219387_DS1.pdf
• File Type:
  [PDF - 728.54 KB ]