Report of Investigations 9638: Distinguishing Motor Starts from Short Circuits Through Phase-Angle Measurements

Details

• Journal Article:
  National Institute for Occupational Safety and Health
• Personal Author:
  Yenchek, Michael R. ; Cawley, James C. ; Peterson, Jeffrey S. ; Kohler, Jeffrey L.
• Description:
  An investigation was undertaken to investigate the characteristics of high voltage underground electrical mining equipment motor start and short circuit waveforms. The aim of the study was to determine a method for providing short circuit protection without intentional time delays to account for motor starts. Computer simulations of power systems identified the requirement for accurate and rapid detection systems. Analyses of high voltage longwall coal mine power systems were conducted using commercial power system analysis software. Distribution voltage, transformer impedance, power center location, and motor size affected magnitude of short circuits and motor start currents. Phase angles between voltage and current were longer for motor starts than for short circuits. A prototype with an induction motor was developed and tested in the laboratory. Minimizing the intentional time delays in short circuit protection will help ensure temperatures of ignition thresholds for gas and dust are not be exceeded on energized electrical apparatus surfaces. [Description provided by NIOSH]
• Content Notes:
  Michael R. Yenchek, James C. Cawley, Jeffrey Shawn Peterson, and Jeffrey L. Kohler.
  
  Investigation by the Pittsburgh Research Center (PRC).
  
  Includes bibliographical references (p. 9).
  
  
• Subjects:
  Electricity Mining Occupational Health Safety
• Keywords:
  NIOSH-Author; Mining-industry; Underground-mining; Mining-equipment; Electrical-equipment; Electrical-properties; Electronic-circuits; Voltage-regulation
• Source:
  Pittsburgh, PA: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 97-120, (RI 9638), 1997 Mar; :1-15
• Series:
  NIOSH Numbered Publications
• Subseries:
  Report of Investigations
• Publisher:
  National Institute for Occupational Safety and Health
• Document Type:
  Text
• Genre:
  Report
• Place as Subject:
  OSHA Region 3 ; Pennsylvania
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  PRL - Pittsburgh Research Laboratory
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  18 pdf pages
• NIOSHTIC Number:
  nn:00238990
• NTIS Accession Number:
  PB97-156723
• Federal Fiscal Year:
  1997
• Peer Reviewed:
  False
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:2e4c60fb6829211802aea8efd761bc10db8b609956d8e540c4f605a7e53518d2c66eff1c6d51e8502e16e2bd65c9f739a6fc8c3750349bf7c7909449d4c430c7
• Download URL:
  https://stacks.cdc.gov/view/cdc/6352/cdc_6352_DS1.pdf
• File Type:
  [PDF - 266.43 KB ]