What is the lubrication method commonly used for small turbines that drive auxiliary equipment?

Oil impregnated bushings are often used in small turbines that drive auxiliary equipment due to their self-lubricating properties. These bushings are made from a porous material that is saturated with oil, allowing them to continuously release lubrication during operation. This characteristic makes them particularly advantageous in applications where regular maintenance is difficult due to space constraints or the design of the equipment.

In the context of small turbines, oil impregnated bushings provide a consistent level of lubrication, reducing the friction and wear on moving parts, which is crucial for maintaining efficiency and prolonging the life of the turbine. This method minimizes the need for external lubrication systems and reduces the risk of mechanical failure due to lack of maintenance.

The other lubrication methods listed may not be as effective or practical for small turbine applications. For instance, grease nipples typically require regular maintenance and may not be suitable for all operating conditions, while ring-oiled bearings are more common in larger, more complex systems. Hand lubrication can be labor-intensive and is generally not appropriate for continuous operation machinery where consistent lubrication is needed.