For nearly six decades, Butler Machinery Company has offered equipment sales, services, and product support for customers, the construction, agriculture, demolition and scrap handling, mining, landscaping, power generation, and on-highway trucking industries. With a fleet of approximately 175 service trucks manned by skilled field service technicians, Butler must be prepared with reliable and versatile equipment for repair, maintenance, and service jobs 24/7.
Butler offers such support services as fleet machine rental; equipment management software and computer software; training and safety videos; and customer training seminars. To meet the wide variety of its customer needs while also lowering fuel and operation costs, Butler decided to convert its truck fleet to EnPak® power systems.
EnPak—a fully integrated power system that provides Butler field service technicians with an air compressor, hydraulic pump, and generator—is powered by a fuel-efficient diesel engine integrated with the truck’s fuel supply and battery. These tools of the trade come in one efficient and dependable machine, providing jobsite capabilities while the work truck’s engine is turned off.


Much of Butler’s service and repair work happens in the field, such as during planting and harvest season and during peak construction periods. When customers call Butler’s technicians to their shop, the technicians use EnPak’s generator to power auxiliary tools or a welder.
EnPak provides a 60 cfm air compressor with air-on-demand delivery, a 20 gpm Eaton hydraulic pump, and a 6,000-watt generator. A 24.8 hp, Tier 4 Final compliant Kubota diesel engine powers EnPak’s 2,400-watt EnVerter™. “It’s all right there. It’s got everything that I need when I’m out working on anything,” says Todd Hammer, Butler field service technician.

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The ability to turn the truck engine off and utilize the machine’s power system reduces fuel usage and truck engine idle time for Butler. EnPak’s diesel engine uses up to 30 percent less fuel than a work truck’s engine and costs up to 79 percent less to maintain. “We’ve noticed a substantial idle reduction with our EnPak-equipped vehicles,” says Kelly Klemisch, fleet manager for Butler. “From a lifecycle perspective, we understand that in two to three years we can return that investment, passing the savings directly to our customers.”
Along with less truck idle time, several technology advancements also play a role in the maximized fuel savings for Butler. An industry-exclusive load-management system monitors accessory requirements and adjusts the EnPak’s engine speed to match demand. This allows EnPak to deliver only the amount of power required, while also allowing for simultaneous operation of the generator, compressor, and hydraulics. “You can plug in multiple things that run, and get everything out that you need,” Hammer says. “It’s more efficient that way. You don’t have to keep unplugging things, looking for power.”
The 6,000-watt generator helps save fuel with EnVerter technology, which delivers up to 2,400 watts of continuous 120-V, 60-Hz, pure sine wave power at low engine speeds. Butler uses the generator to power tools and equipment, including welders, lights, laptops, and cell phones.
Featured image: EnPak’s fuel-efficient diesel engine is integrated with the truck’s fuel supply and battery, allowing workers to perform without truck idling.
Above: EnPak allows workers to power the tools they need.


EnPak’s load sensing and auto start/stop technologies contribute to ease of operation. “It’s one less thing field techs need to worry about when they’re on a job,” Klemisch says. “They don’t need to switch on or switch off a machine. It basically does it on its own.”
Butler workers also noticed the enhanced cfm capabilities, which can drive a wide variety of tools with high airflow capacity. The air-on-demand delivery system eliminates the lag time common with other air reservoir systems, so Butler workers can instantly engage the compressor in response to loads to deliver quickly the required air pressure. “We’ve noticed increased air compressor performance, which has really been a benefit to our technicians,” Klemisch says.
When using the hydraulic pump, Butler workers get smooth, reliable, and precise crane operation. A low-speed lock function enhances control, minimizing hydraulic flow for maximum precision. “You can change the engine speed, which also will change the speed of the crane,” Hammer says.


Reducing engine idle time not only provides fuel savings, it also results in maintenance savings for Butler. The company is able to reduce the frequency of maintenance, lowering costs for preventive maintenance as a result. This is especially useful when truck engines that are Tier 4 compliant require the servicing of emissions-control equipment.
The EnPak diesel engine does not require diesel exhaust fluid and has no diesel particulate filter to clean or replace, further simplifying maintenance for Butler. Reducing truck engine idle time by relying on the system for jobsite functions also helps extend the life of the truck drivetrain, so Butler expects to use fleet trucks longer.
Using the unit along with a smaller suitcase welder saves Butler about 150 pounds of truck payload, compared to carrying a hydraulic air compressor and an auxiliary welder. “We believe that we can extend our asset life, especially our Class 5 trucks, at least a year or two,” Klemisch says.


In addition to the fuel, maintenance, and asset lifecycle savings, the machine improves the working environment for Butler employees. Turning the service truck off instead of running it in idle reduces truck emissions and noise. In addition, the auto start/stop technology reduces noise and exhaust emissions, because the engine only runs when there is a load detected. A specially designed enclosure further reduces sound output.


EnPak is integrated with the truck’s fuel supply and battery, which eliminates the need to fill more than one fuel tank. The techs don’t need to climb up and down from the truck to fill an auxiliary fuel tank, which improves safety. Workers can also easily access the controls on the external control panel, so there is no need for techs to climb up onto the truck to operate the system.
The fuel and maintenance savings realized, combined with quality performance for a wide variety of jobs, has made this work truck solution a good investment for Butler. In addition, the machine’s reliability and the resulting increased uptime will help Butler serve customers better. StoryStopper-Icon


Find out more about Miller EnPak at


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