New Speed-Governing Tech for Engine-Driven Welder-Generators Improves Fuel Efficiency and is Quieter
With most gasoline and diesel engine-driven welder/generators, idle and high speed are the only options when it comes to engine rpms. Unlike low-speed diesel machines, operating at a top run-speed of 1,800 rpm in higher amp-class machines, the welder/generators in this engine category will idle when there is no load applied to the engine and ramp up to a full speed of 3,600 rpm when any load is applied, no matter how much power is actually needed.
With any weld or auxiliary load causing welder/generators of this type to run continuously at full speed, they will consume more fuel and generate more noise than necessary. Improving fuel efficiency and reducing noise output can have a major impact on the profitability of your project and the safety of your jobsite.
Technology advancements make that possible. Miller-exclusive Auto-Speed™ technology, available on all Trailblazer® welder/generators, provides significant improvements in fuel efficiency while noticeably reducing noise levels — so operators can maximize uptime, reduce fuel costs and keep their jobsites quiet.
Auto-Speed enhances performance by automatically selecting the appropriate engine speed to match the weld load requirement. Using this technology, the machine automatically ramps up when more power is needed for a welding application but runs at a lower speed whenever possible for the job. The result is simple: Operators get all the output needed to weld and run tools while consuming minimal amounts of fuel and generating the least amount of noise in the process.
How it works
The technology operates by having a power management system built into the welder/generator. It senses the weld load needs for each application and sends a command signal to the engine to match the engine rpms to the load requirement. On gasoline Trailblazer models, the controls choose from four available speeds — 2,400 rpm (idle/150 amps); 2,800 rpm; 3,200 rpm and 3,600 rpm (high).
On the new Trailblazer 325 Diesel welder/generator, Auto-Speed technology adjusts engine speed to one of five rpm levels, so the engine never works harder than necessary. Operators can weld up to 135 amps while the engine remains at idle (1,800 rpm), saving up to 15 percent in fuel over competitive units and drastically reducing jobsite noise. Rated at 70 decibels at idle, no other diesel-fueled welder/generator in this category is as quiet.
The control works in different ways depending on the welding process being used and the output required. When using a stick or TIG welding process, the control predetermines engine speed based on the operator’s preset amperage setting. If the welder presets 125 amps, the technology knows the load requirement and will adjust rpm accordingly.
To compensate for stick and TIG arc starts, which require more load, the control adjusts rpm to one speed higher than the preset amperage and then lowers the engine speed after arc initiation. This allows welders to get premium arc starts while using only the fuel required to run the preset amperage. If long arcing occurs, the control will increase engine speed to accommodate the higher power needs.
When a welder is using a MIG process, the engine automatically goes to a speed that gives enough load to start any wire size. Once the arc is initiated, the control mechanism calculates the load required and corrects engine speed. For higher amperage welds, when more power is needed, the engine will continue to increase in speed, whereas it will decrease for welds that demand less amperage.
To keep the engine from constantly changing speeds based on weld load requirements, the technology monitors and calculates load needs, to limit the number of times the engine will go up and down based on those needs. This helps avoid having an engine speed that is constantly changing but ensures operators get all the power necessary for the job.
Control of auxiliary power
In addition to the Auto-Speed feature, a second Miller-exclusive technology allows users to run most jobsite tools at 2,400 rpm to save fuel and reduce noise. This technology — Excel™ power — is optional in the electronic fuel injection (EFI) Trailblazer models and is also available on diesel models. With Excel power, welders get 2,400 watts of pure 120-volt, 60-hertz generator power, completely separate from the machine’s standard generator power. This allows operators to run tools and low-amperage welding arcs simultaneously at idle speed.
What speed regulation means for fuel efficiency
Many jobsite applications can be completed at power levels lower than those allowed by typical welder/generators in this category. For example, a common application on jobsites is welding a 1/8-inch 7018 stick electrode. With speed-governing technology, welders can complete this type of welding all day and never have the machine come out of idle.
Any stick, TIG or MIG welding application that runs at less than 150 amps (gas) or 135 amps (diesel) can be completed at idle. Welding processes that use 150 to 200 amps have a 2,800-rpm continuous load with this technology, while welding applications that need 200 to 250 amps require a 3,200-rpm continuous load. Amperage requirements above 250 amps run at 3,600 rpm. (These are all approximate thresholds for gas model rpm changes.)
When jobs are completed using a lower engine speed, the result for welders is greater fuel efficiency. A machine with speed-regulating technology can save about $460 per year in fuel costs when compared to a machine without it, according to field testing. Additional fuel savings can be realized when speed-governing technology is combined with other optional technologies that make welder/generators more efficient.
Greater fuel efficiency also equates to longer runtimes for welders on the job, which can help increase productivity. Less time spent on refueling means more time doing other value-added activities.
Reduced noise can improve safety, productivity and comfort
Another benefit that welding operators will notice is quieter operation, since a machine that spends more time at lower speeds produces less noise.
Reduced noise levels can help improve safety and communication between workers on the job, giving workers the ability to better hear what’s happening around them. Less noise also means a more comfortable environment for the welder and anyone else working in the vicinity of the machine.
Quieter operation means the welder/generator often can be used earlier and later, especially on jobsites in noise-sensitive areas, such as residential neighborhoods or near hospitals. This can make completing jobs a faster process, which helps contractors boost productivity and become more competitive in bidding. It’s also easier for welders to hear the arc when the machine produces less noise. Some operators use sound as a way to monitor weld quality, so this is another benefit that can result in productivity gains.
Payback over time
Cost considerations are important to many businesses, contractors and welders when choosing a welder/generator. Technology advancements that offer efficiency and productivity benefits may have a higher up-front cost, but those benefits can offer greater payback over the life of the machine.
In addition to potential fuel savings and productivity gains, the ability to spend more time under the hood or powering tools — and less time running to get fuel — can make a difference in how quickly a project or job is completed.
Realizing the benefits
Welder/generators are valuable and versatile machines used on construction jobsites and work trucks; in fabrication shops; for service, maintenance and repair work; and throughout the oil & gas industry, just to name a few applications.
The bottom line: Welders can get numerous benefits from improved fuel efficiency and reduced noise when using welder/generators with Miller-exclusive Auto-Speed technology.
Note: The speed-regulating technology discussed in this article applies to gasoline and variable-speed diesel engine-driven welder/generators. Miller also offers a full line of low-speed diesel engine-drives that operate at a top run speed of 1,800 rpm, which reduces noise and contributes to significant fuel savings.