Final answer:
Hydraulic pumps in heavy machinery such as backhoes are driven through various methods. Primary hydraulic pumps are typically engine-driven, while secondary and auxiliary pumps can also be electric or use secondary power take-offs. These systems leverage Pascal's principle for force multiplication.
Step-by-step explanation:
The question 'How are the primary, secondary, and aux hydraulic pumps driven?' involves understanding the driving mechanisms of different types of hydraulic pumps used in heavy machinery such as backhoes. In general, hydraulic pumps are driven by several means depending on their design and the applications they are used for.
Primary Hydraulic Pumps
Primary hydraulic pumps are typically driven by the engine of the equipment directly through a gear, belt, or shaft connection. In some cases, the primary pump is a variable displacement pump that can alter its output to match the hydraulic demand of the system.
Secondary Hydraulic Pumps
The secondary hydraulic pump, often a constant displacement pump, is usually powered in a similar manner to the primary pump but may serve a specific subsystem or provide additional power when needed.
Auxiliary Hydraulic Pumps
As for auxiliary hydraulic pumps (aux pumps), which are used for auxiliary functions of the machinery, are often driven electronically or by secondary power take-offs from the engine, ensuring they can operate independently of the primary system when required. Motorized pumps, as those in power brakes and bulldozers, do most of the work, leveraging electric motors for function.
In regards to the backhoe example provided, the application of Pascal's principle in hydraulic systems allows the multiplication of forces to move heavy loads using cylinders of different diameters. By applying a smaller force to a smaller-diameter primary cylinder, you can create a pressure that can lift a much heavier load with a larger-diameter secondary cylinder due to the mechanical advantage offered by the system.