Gene Finner of Dow Corning will delve into the details of eliminating mechanism seizures and slow trip times at the Finepoint Circuit Breaker Test and Maintenance Training Conference in October. Finner, who is an applied-engineering technical service professional for Molykote lubricants, will examine how lubricants help or hinder the operation of this equipment.

Finner has held his current position at Dow Corning for 10 years. Dow Corning is a global company headquartered in Midland, Michigan, with about 9000 employees and roughly 25,000 products, and is a global leader in silicon technology.

“I’m going to use the trip-coil bearing in motor spring-actuated breakers as an example of one possible cause of delayed trip,” Finner said. “In a nutshell, the trip-coil bearing acts as a hair trigger to set off the spring tension and trip a spring-actuated breaker.” If the bearing is hindered, it may rotate too slowly and contribute to a delayed trip.

“Grease” selection and application based on environment and maintenance intervals may be helpful in avoiding these problems.

Finner will present information on physical properties of two to four commonly used greases in the power utility industry, and he will talk about why one may work well in a given environment and another may work, but not as well.

Ambient temperature and the amount of grease applied are two points to consider when greasing these bearings. Temperature plays a significant role in determining how well a given bearing will move through any specific grease and how long the service life of that grease will be.

“Some of the other moving components in the mechanism of that type of breaker mechanism are pins, cams, bearings,” Finner said. “After the trip-coil bearing acts on the trip latch, the energy stored in the spring will provide the force to trip the breaker so the other components are not going to be as temperature-sensitive as the trip-coil bearing.” These components can be lubricated with less regard to ambient temperatures. “Perhaps it is more important to consider seizure and keeping the components lubricated with long-lasting low coefficient of friction materials--that also have some decent corrosion protection built into them,” he said.

Here too, Finner will offer some thoughts on strength and weakness of lubricating greases and pastes that could be used to lubricate these components.

Finner’s session will take place on Oct. 3.