Page 5 of 6
Fluorosilicone grease lubricants offer resistance to solvents used in aerosols and penetrating oils.
Penetrating oils should be thought of and used only to free up seized parts and to bust rust.
Penetrating oils do not provide any meaningful long-term lubrication and, as stated previously, the bulk of their volumes will remain in service for only a few hours before it evaporates away completely. Devices treated with penetrating oils will move freely for short time periods, but upon evaporation the device will return to sluggish movement or seized condition. Application of penetrating oil can make a situation worse than it was by removing more grease from the device by solvent wash out.
Aerosols are formulated with about 5-10 percent actual lubricant, with the remaining content of the can consisting of solvent and propellant. While ease of use is high and the solvents do allow some penetrating action, the end-user needs to exercise caution when using aerosol products. It can be easy to apply lubricant beyond the area where it will be effective, and possibly mix the aerosol lubricant with another lubricant that might result in lubricant incompatibility.
Dry film lubricants have found acceptance in automotive component and fastener applications.
Piston skirts and rings, door pins and trunk and door latches, as well as threaded connections, are examples of parts that are treated with dry film lubricants to impart long-term lubrication or corrosion protection to them. Some initial evaluations of dry film lubricants in components of high voltage electrical equipment have produced promising results.
Dry film lubricants are applied and formulated similar to paint – they are brushed, sprayed or screen printed onto the part in question, then cure by solvent evaporation, followed by resin binder cure that binds a layer of additives to the substrate that the coating was applied to. Once dry, the films can adhere with great effectiveness. One other key benefit of dry film lubricants is they dry tack-free. This is a significant benefit considering the dust, dirt and other contaminants that can adhere to wet lubricant coatings.
Dry film lubricants work best in applications where speeds are slow and loads are heavy. Many of the most robust dry film lubricants must be applied in thin, uniform layers and heat cured; the application process is critical to overall success and often best left to an expert coating shop. The application of dry film lubricants can limit them somewhat to equipment manufacturers who have their original parts coated before installing them in their equipment. Coating certain pins, gears and threaded parts on breakers and disconnects might offer a chance to reduce failure from seizure and decrease required maintenance for the end-user, since these coatings could yield maintenance-free service lives measuring several years to more than a decade. It seems worthy of further investigation of usefulness of dry film lubricants in circuit breaker and disconnect switch applications.
Mineral oil & synthetics
Grease and industrial oil can be classified as either mineral oil or synthetic.
Mineral oil originates from crude drawn from underground wells. Crude is refined and distilled to produce the cuts of oil used to form finished lubricants. These cuts often contain high levels of impurities that are responsible for short lubricant life, poor performance at temperature extremes and high levels of volatility. Volatility can be noted by the odor of aromatic compounds in some mineral oils.
Synthetic lubricants all have one thing in common – all originate from a chemical engineering process and have been built to meet a certain set of physical properties, including superiority to mineral oils in thermal and oxidative stability and better extreme temperature capability.