Journal of the Korean Society of Safety (한국안전학회지)

The Korean Society of Safety (한국안전학회)
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Characteristic of Current and Temperature according to Normal and Abnormal Operations at Induction Motor of 2.2 kW and 3.7 kW

2.2 kW와 3.7 kW 유도전동기의 정상과 구속운전에 따른 전류 및 온도 특성

  • Jong-Chan Lee (Safety & Health Management Office) ;
  • Doo-Hyun Kim (Department of Safety Engineering, Chungbuk National University) ;
  • Sung-Chul Kim (Department of Safety Engineering, Chungbuk National University)
  • 이종찬 ((주)KT&G 안전보건관리실) ;
  • 김두현 (충북대학교 안전공학과) ;
  • 김성철 (충북대학교 안전공학과)
  • Received : 2023.02.20
  • Accepted : 2023.06.14
  • Published : 2023.06.30
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Abstract

This study analyzed the current and temperature characteristics of major components of an induction motor during normal and abnormal operations as functions of the difference in the rated capacities of medium and large-sized motors widely used in industrial settings. The temperature rise equation of the induction motor winding was derived through locked-rotor operation experiments and linear regression analysis. When the ambient temperature is 40 ℃, the time to reach 155 ℃, the temperature limit of the insulation class (F class) of the winding of the induction motor, was confirmed to be 48 seconds for the 2.2 kW induction motor and 39 seconds for the 3.7 kW induction motor. This means that when the rated capacity is large or the installation environment is high temperature, the time to reach the temperature limit of the insulation class during locked-rotor operation is short, and the risk of insulation deterioration and fire is high. In addition, even if the EOCR (Electronic Over Current Relay) is installed, if the setting time is excessively set, the EOCR does not operate even if the normal and locked-rotor operation of the induction motor is repeated, and the temperature limit of the insulation grade of the winding of the induction motor is exceeded. The results of this study can be used for preventive measures such as the promotion of electrical and mechanical measures for the failure of induction motors and fire prevention in industrial sites, or the installation of fire alarm systems.

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References

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