Abstract
As important power cables for the mining mobile equipment, such as mining shearers, ethylene propylene rubber (EPR) cables often suffer from the combining effect of various stresses on site. In order to evaluate the aging state of EPR insulation, the paper carried out the multi-stress accelerated aging test on the insulation of coal mining flexible EPR cables. The infrared spectrum, elongation at break and polarization and depolarization current of cable insulation samples were measured. The insulation state of EPR cable was evaluated by using the aging factor obtained from isothermal relaxation current. Based on the failure standard of 50% elongation at break, the life formula of EPR insulation was deduced. The experimental and analytical results show that the tiny air gap was torn to the larger air gap under the mechanical stress, which leads to the increase of oxygen infiltration and promotes the thermo-oxygen reaction. The fracture energy of EPR decreases, and mechanical aging is accelerated. Aging factor and elongation at break can indicates the deterioration degree of EPR insulation. Based on the least square method and Arrhenius equation, the service life of the insulation of coal mining flexible EPR cables is deduced.
Highlights
Ethylene Propylene Rubber (EPR) is synthesized by ethylene, propylene and non-conjugated dienes
Coal mining EPR cables are often subjected to mechanical stress such as extrusion and tensile stresses, as well as thermal stress caused by the frequent start and stop of motors with the heavy load, so EPR insulation is always aged and deteriorated rapidly
The results shown that the product of the depolarization current and time t of cables shown a relationship with the aging time [12]
Summary
Ethylene Propylene Rubber (EPR) is synthesized by ethylene, propylene and non-conjugated dienes. L. Lin et al.: Aging Life Evaluation of Coal Mining Flexible EPR Cables Under Multi-Stresses. Lots of researches have paid attention on the insulation life evaluation, the aging evaluation of EPR cable used in coal mine is unavailable, especially under the multi stresses, such as electrical, thermal and mechanical stresses [13]. In order to evaluate the insulation aging state of EPR cables for mining under multi-stresses, the accelerated aging test was carried out in the lab. For analyzing the effect of temperature on aging, new samples were aged at the temperature of 120 ◦C, 135 ◦C, 150 ◦C and 165 ◦C for 200 hours, respectively In this case, the applied voltage and mechanical stresses were the same as aging test at 100 ◦C. The dumbbell type sample was made in accordance to the Chinese national standard, GB/T 528-2009
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
