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Lubrication of Distribution Electrical Equipment
Published in Bella H. Chudnovsky, Transmission, Distribution, and Renewable Energy Generation Power Equipment, 2017
Grease has a maximum temperature at which it can safely be used. This critical temperature is called the drop point at which the gel structure breaks down and the whole grease becomes liquid. When grease is heated above its drop point and then allowed to cool, it usually fails to fully regain its grease-like consistency and its subsequent performance will be unsatisfactory. Accordingly, if the temperature of CB-lubricated components in operation is higher than the upper limit of the lubricant working temperature range, it could leak out at high temperatures, which will affect the mechanical performance of the parts or expose them to corrosive environment.
Grease Lubrication
Published in W. S. Robertson, Lubrication in Practice, 2019
The drop point is the temperature at which the grease flows under gravity. This is not therefore the maximum temperature at which the grease can be used. This depends on many factors and there is no hard and fast rule. For example, the drop point of a simple calcium grease would be about 100 °C but service experience has shown that the maximum temperature for continuous use should not exceed 60 °C. In the case of lithium hydroxystearate greases the drop point is about 180 °C but the maximum temperature for continuous operation should not exceed about 120 °C, although occasional peaks of temperature up to 150 °C can be permitted.
Lubrication of Distribution Electrical Equipment
Published in Bella H. Chudnovsky, Electrical Power Transmission and Distribution, 2017
Thermal limitations, both high and low, represent major factors in the durability of many lubricants (see Section 4.4.5). At low temperatures, many lubricants appear to solidify, developing high-shear-strength films, and leading to high CR. Some lubricants are susceptible to cracking due to long-term exposure to high temperature. Grease has a maximum temperature at which it can safely be used. This critical temperature is called the drop point, the point at which the gel structure breaks down and the whole grease becomes liquid.
Tribological behavior of ZnO-Si3N4 nanoparticles-based lubricating grease
Published in Journal of Experimental Nanoscience, 2018
Qiang He, Anling Li, Zhigang Wang, Yong Zhang, Linghao Kong, Kang Yang
As one of major reasons for materials failure, friction and wear is attracting more attention [1]. Up to now, it is still a challenge for the world to develop a tribological system that is antifriction, wear resistant and capable of self-repairing [2]. Grease is an indispensable lubricant used in mechanical equipment, which can help to decrease friction and wear, as well as prolong the service life of equipment. Lithium lubricating grease, which is featured by high drop point, multiple effect and high adaptability, has been widely applied in industrial fields such as mechanical engineering, aeronautics and astronautics.
Tribological and rheological properties of the lubricant containing hybrid graphene nanosheets (GNs)/titanium dioxide (TiO2) nanoparticles as an additive on calcium grease
Published in Journal of Dispersion Science and Technology, 2022
Bahaa M. Kamel, Enas l. Arafa, Alaa Mohamed
The dropping point shows how resistant the fluid is to heat. The drop-point of the fluid is defined as the temperature at which the first drop of fluid emerges from the cup’s bottom hole. This test measured the nanofluid according to ASTM D-566 [29] by adding a small amount of approximately 0.8 g of nano grease to the cup and then heating until the first drop of fluid falls from the hole in the bottom of the cup. In addition, the dropping point depends on the thickener type.[30]