Influence of tribocharging on the work of lip seals in a model engine

The paper presents the results of preliminary tests upon the tribocharging of some engine and gear oils and one transformer oil, as well as two different lip seals for comparison. Experiments were carried out using a simplified model of an engine in whose interior a metal shaft was rotated with given angular velocities from 500 up to 4500 rpm maximum. The potential of a sealing seating was measured with an electrometer, and this potential is proportional to a zeta one, as assumed. The effect of the elevated temperature of the oil on the torque was also investigated. The results of the preliminary tests are presented in the form of some characteristics that are relationships of the braking torque and of the potential induced in the housing of a seal to the angular velocity of a shaft and to the temperature of the oils examined; these relationships show that there is an influence of tribocharging of the oil and seal on the increasing torque.