The David W. Taylor Naval Ship Research and Development Center is conducting research on the development of a condition-monitoring technique for electric motors. The technique, aimed at providing an uncomplicated quality assurance check, is a practical means of assessing the mechanical condition of an electric motor by measuring its coastdown time after repair or overhaul has been completed. Coastdown is that time required for a rotating mass to become motionless after the power is shut off. Measured coastdown time is compared with a calculated coastdown time based upon motor, bearing, and lubricant parameters. Since the dissipation of the kinetic energy during coastdown depends upon friction, the coastdown time provides a measure of friction and is, therefore, an indicator of the mechanical condition of the motor. Significant deviation between the calculated and measured values is evidence of a probable mechanical problem and signals the need for investigation. But when the two values are in agreement, the motor is properly assembled and ready for shipboard use. The motor will then begin its service life in sound mechanical condition and it can be expected to provide a higher probability of trouble-free, mechanical operation. (No further information in article)

  • Corporate Authors:

    Office of Naval Research

    Department of the Navy, 800 North Quincy Street
    Arlington, VA  United States  22217
  • Publication Date: 1976-11

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Filing Info

  • Accession Number: 00147548
  • Record Type: Publication
  • Source Agency: Office of Naval Research
  • Files: TRIS
  • Created Date: Feb 16 1977 12:00AM