From enhancing efficiency to powering complex equipment, understanding the ins and outs of HPU design can save businesses both time and money. One of the seasoned experts at Bailey International regularly explores common challenges, best practices, and tips for success.
MWS spoke with Bill Keller, Engineering Manager HPU/Tech Support at Bailey International, and here is what he had to say about optimizing HPUs for work trucks.
MWS: HOW DID YOU BECOME INVOLVED IN THE CUSTOM HPU DEPARTMENT AT BAILEY INTERNATIONAL?
BILL KELLER: Oddly enough, my career did not start out in hydraulics; I was an ISO 9000 quality auditor for several years. When starting with Bailey, I began in customer service. Back then, we were a small family-owned company. Spending a lot of break time in the warehouse and manufacturing areas soaking everything in like a sponge. Over time, two colleagues and myself were (unofficially) designated the “tech guys,” and started having the more technical questions directed towards us.
I developed an interest in systems in general, and power units specifically. When a position in engineering opened in HPU design, I applied, got the job, and never looked back. As a designer for 12 years, I interacted with every aspect of the business: sales, supply chain, manufacturing, you name it. This allowed a seamless transition into now leading our HPU designers and technical support staff.
MWS: WHAT DRIVES YOUR PASSION FOR HELPING BUSINESSES OPTIMIZE THEIR HPUS?
KELLER: One of the joys of this job is seeing what companies are doing with our power units. Where one company builds a huge contraption that can pick up and empty a tractor trailer, another one makes boat lifts, and another makes a machine that deploys solar panels. What they all have in common is they use Bailey’s power units. We have hundreds of these awesome stories, each with a different challenge we had to overcome.
AVOIDING COMMON MISTAKES
MWS: WHAT ARE THE MOST COMMON HPU DESIGN MISTAKES BUSINESSES MAKE?
KELLER: One huge mistake is not understanding this basic rule of thumb: For every one gallons per minute of flow per 1500 psi, you will need one horsepower. For example, if you want two gpm at 1500psi, you will need two hp; if you want one gpm at 3000psi, you will still need two hp. Some customers just won’t do the math and end up over or underestimating their horsepower needs.
MWS: HOW DOES THAT IMPACT PERFORMANCE AND BUDGETS?
KELLER: If someone overestimates their horsepower needs, typically excess power does nothing but build up heat throughout the entire system. This shortens the lifespan of the oil and all the seals in the system, greatly inflating maintenance costs and increased energy costs. Underestimating horsepower can cause even greater problems; if you don’t have enough power to overcome the pressure, at best the load will not move, at worst your motor will stall, and you’ll see smoke.
MWS: CAN YOU SHARE AN EXAMPLE OF IMPROPER HPU DESIGN THAT CAUSED ISSUES?
KELLER: We have another customer who builds something similar to dump tractor trailers. They “did the math,” and the motor (40 hp), pump (50 gpm), and tank (200-gallon JIC) were all sized correctly. Most of our custom units include a relief valve to protect the pump and motor, and a return filter, and they also wanted us to add a couple of 1-1/2” ports to the top of the tank.
We built and tested the unit and sent it to them. When they got it, they added their own control valves and moved the return filter to the other side of the tank. This caused the filter to be less than six inches from the pump, so that the oil that was coming out of the return filter was immediately pulled back into the pump. The oil had no time to cool down or aerate (release any gases that get trapped during operation).
They contacted us asking us to make those changes, and we explained why we placed the filter away from the pump. As it turns out, they moved the filter to shorten the hose from their valve, saving a few dollars in hosing. It could have cost hundreds more in increased wear. They trusted our reasoning and moved the filter back to its original location.
BEST PRACTICES FOR WORK TRUCK HPUS
MWS: WHAT STEPS SHOULD BUSINESSES TAKE TO ENSURE PROPER HPU SIZING?
KELLER: Step one is to understand the power you have available. Is it going to be on a piece of mobile equipment? Do you need DC or a gas-powered unit? Residential or small workshop? Most likely will need single-phase AC. Industrial or large workshop? Three-phase AC will do. What follows is which actuators you will use, their speed and load. As you answer each question, your design needs become clearer.
MWS: WHAT ROLE DOES TESTING PLAY IN VALIDATING HPU PERFORMANCE?
KELLER: Every power unit we build, from the smallest to the largest, gets put through its paces before it ever leaves our shop. We test its performance, all the valves (for both leak and function), and pre-set the relief valve. If something isn’t right, then it’s a full stop and we make it right before moving on.
TRENDS AND INDUSTRY INSIGHTS
MWS: HAVE YOU NOTICED TRENDS IN IMPROVING HYDRAULIC EFFICIENCY?
KELLER: As the costs of some proportional components have been decreasing, they are starting to be within reach for customers who want more control of their hydraulic systems.
MWS: HOW HAS THE INDUSTRY EVOLVED TO ADDRESS COMMON CHALLENGES?
KELLER: For the past 15 years, Bailey has had dedicated technical support professionals available to speak with any of our customers. We help troubleshoot, listen to ideas, and have even sent some customers to competitors if we didn’t have a solution.
EXPERT TIPS FOR WORK TRUCK PROFESSIONALS
MWS: ANY ADVICE FOR WORK TRUCK PROFESSIONALS LOOKING TO AVOID HPU-RELATED DOWNTIME AND INEFFICIENCIES?
KELLER: You need to look after your hydraulics in the same way as changing engine oil in your trucks. Check your hydraulic fluid. Is it low? Do you have sediment in the tank? Set up a schedule based on your usage; understand when you need to change the oil, flush the system, or repack the cylinder. Don’t forget that little HPU tucked behind the rear bumper.
MWS: CAN YOU SHARE A TIME WHEN YOUR EXPERTISE MADE A SIGNIFICANT DIFFERENCE FOR A CUSTOMER?
KELLER: A customer had designed a system that raised and lowered solar panels. It was on a trailer, and they were using a DC power unit with a 12v permanent magnet motor (most 12v DC units have field wound motors). They assumed they needed the larger motor because they thought they had to run them continuously.
When it became harder for them to obtain those motors, they turned to us. We looked at the entire system, the cylinder geometry, and what deploy speeds they were looking for. The bottom line is they did not need that PM motor. This saved them over $1,000 per unit, not to mention the decreased lead time.
KEY TAKEAWAYS
Hydraulic power units are the backbone of countless work truck applications, but proper design and maintenance are essential to maximizing their lifespan. By collaborating with experts, conducting thorough needs assessments, and prioritizing maintenance, your fleets can minimize costly errors and maximize performance. At the end of the day, it’s the partnerships, innovation, and problem-solving that make this work exciting and rewarding.
about the interviewee
Bill Keller has over 12 years of design experience and leadership managing technical support staff. His career at Bailey International has spanned customer service, engineering, and now management, giving him a unique, comprehensive understanding of the hydraulic system industry.
