An alternate technique for selecting a pump drive is called the power method, but this should be used only if the torque is unknown.

1. Determine the net peak power (hp or kW) transmitted to the pump drive from the prime mover.

2. Determine the equivalent power (hp or kW) by multiplying the net peak power by the appropriate service factor for the application. Take into account the engine output characteristics, as well as the equipment’s expected daily hours of use.

3. Using the equivalent power, select the proper pump drive series with a maximum input power capacity that exceeds the equivalent power of the hydraulic pumps.

Both methods require the following additional steps for determining the proper pump drive configuration:

A. Determine the number of pump pads required by making a selection from the models available within the pump drive series. Be sure to take into consideration the maximum output torque rating per pad, and the center distance between the mounting pads for clearance of the pumps and their hydraulic plumbing.

B. Select a gear ratio from the options available for the selected model that will provide the desired pump speed and flow. Be sure to consider the maximum recommended speed for both the pump drive series and the hydraulic pumps being used.

C. Select the desired input configuration from the available options for the pump drive series:
• engine mounted — drive plate or torsional coupling driven,
• engine mounted — clutch-driven (consider clutch limiting speeds and torque capacity), or
• remote mounted. D. Select the desired output configurations from the available options for the pump drive series:
• pump adapter plates,
• Pump shaft adapter sleeves (if required), and
• drive shaft or PTO options.

The manufacturer of the pump drive box can assist in determining whether the configuration will meet an application’s requirements, including expected durability for the specified duty cycle. Most manufacturers will be able to assemble the initial package and modify it as necessary if requirements change.

Additional considerations
The presence of unwanted torsional resonant frequencies in the system can quickly cause damage to components in the drivetrain and reduce the life of the components. The engine manufacturer, torsional coupling supplier, or an independent consultant can perform torsional vibration analysis.

Also ensure that a service and support network is in place when specifying a pump drive. The benefits of a modular assembly system and an experienced regional distribution network can be instrumental in keeping equipment up and running.

Getting the most out of your equipment often depends on close integration between all components. A company that manufactures and integrates all the diverse components of a drivetrain provides the experience to help you select the best pump drive for the application.

For more information, contact the author via e-mail at reeveswilliame@johndeere.com