End users and machine builders must find common ground to implement more efficient actuation tech and go green – in more ways than one
When it comes to energy efficiency, our gears are always turning. And it’s not just for feel good vibes – there are countless good reasons to make industrial motion control consume less power. Sustainability is increasingly important as businesses look to the future and work to meet new standards. But it also just makes good business sense.
Of course, no one sets out to waste more money and resources, not to mention floorspace and engineering effort, on inefficient equipment. What often causes these situations is miscommunications between the OEM and the end user. Rather than focusing on the total cost of ownership, the two more often duke it out over the upfront costs.
Providing a cost-competitive system that meets all throughput and quality requirements is certainly important. But that can ignore some long-term considerations. So how do you build a more comprehensive plan?
Energy efficiency in motion control must take a two-pronged approach. First, machine builders need to take a long-term view of component selection. Second, OEMs and end users must start capturing all the electricity that’s simply wasted to make the plant overall more efficient. Let’s check out a few examples of both.
Electric cylinders push the limits of energy efficiency
At the device level, energy efficiency in motion control is really a mixed bag. Rotary motion technologies keep evolving in ways that save energy. But linear motion faces continued challenges, especially in high-speed, high-force actuation applications.
Traditionally, pneumatic or hydraulic cylinders were used in these scenarios. But on top of their requirements for excess footprint, they’re extremely inefficient tools. Pneumatic and hydraulic actuators need to constantly run compressors or pumps, respectively, even when the cylinders are idle. So their efficiency rates average 10-25% for pneumatics and about 40% for hydraulics. However, with damaged seals, leaky hoses and general wear, those numbers drop in short order.
Here, electrification offers a clear path forward. Electric cylinders consume power when enabled and while the cylinder is in motion, so their rate of efficiency can be measured up to 80%. While most will immediately note the higher price when compared to the cost of a traditional solution, electric cylinders offer an optimal TCO and a much faster ROI through the combination of higher efficiencies, reduced maintenance and enhanced ease of use.
The advances in electric cylinder technology ensure you don’t have to sacrifice performance to gain these advantages. The AA3000 series electric cylinders from Beckhoff, for example, offer peak forces of 6.5-25 kN with stroke lengths from 150 mm (5.9 in) to 250 mm (9.8 in).
These feature-rich devices include an integrated safety encoder, temperature and current monitoring for predictive maintenance, and auto configuration that simply requires you to scan in the electronic nameplate. This removes the mystery of implementing these systems, which previously felt closer to “dark arts” than engineering.
The Beckhoff electric cylinders’ optimal mechanical designs deliver direct-drive solutions, with no belt or gearbox, and a backlash of just 15 µm. By selecting an ISO 15552 compatible AA3000 electric cylinder, you’ll have a direct drop-in replacement for pneumatics or hydraulics. So you can easily adapt machine designs or even retrofit legacy equipment. As a result, you can make wide-ranging motion systems more efficient on the component level.
Greener plans with effective regen recovery
When looking at the plant or just machine level, eliminating compressors, pumps and other energy-leeching devices can have some effect. But that doesn’t account for all the perfectly usable energy that often goes untapped. Engineers often handle regenerative energy in motion systems by bleeding it out through a braking resistor. It’s an age-old, low-tech answer to a complex problem. And it’s ripe for an update.
Now, with universal energy recovery modules, end users can route that electricity back into the power grid. You simply connect an AX8820 energy recovery module from Beckhoff to the 24 V DC supply on the drive and your mains, along with a DC-link connection. The device manages braking power as it gets kicked out by the drive, with an integrated mains choke and filter to help stabilize energy recovery. So the sinusoidal regeneration includes all required inductors and filters, and it has no mains distortion.
By adding the AX8820 to new designs, OEMs can guarantee their machines deliver the utmost efficiency. These modules are ideal for Beckhoff AX8000 and AX5000 series Servo Drives, but they also function as a universal energy recovery device. That means end users can add AX8820 modules to existing equipment with various third-party motors and drives and still capture the energy that would otherwise be wasted.
Universal energy recovery modules that have an EtherCAT connection allow for monitoring of these savings as well. Engineers can connect the unit to a central PC-based controller and access the data locally or at a higher level. For some units, this doesn’t require any special configuration. Implementing these connected technologies in greenfield or brownfield environments helps global companies ensure they’re hitting their sustainability targets.
Even with a reasonable price point on these modules, it’s important to know what kinds of savings they’ll provide before making the investment. Beckhoff offers two tools to help:
Motion Designer. While this feature-rich configuration toolset built into TwinCAT 3 automation software is known for sizing your servomotors and servo drives, it can do much more. Motion Designer calculates regenerative braking power in kilowatt-hours for any motor-drive combination, and it translates that into a dollar amount that you would save by adding an AX8820.
TwinCAT Analytics. Today’s plants must measure and visualize an abundance of data, so it’s no surprise that braking power can also be included alongside other production metrics. TwinCAT Metrics can monitor drive performance during operation by measuring the DC-link voltage. This helps you measure the real-world savings and make adjustments to ensure you’re hitting necessary targets.
Using these two tools, you can evaluate whether your motion application would save a few dollars or a few thousand dollars per year using AX8820 energy recovery modules. For the right application, these devices empower more sustainable operations.
A comprehensive look brings things into focus
Updating your motion control with electric cylinders and regenerative energy solutions greatly reduces TCO on any piece of equipment – especially when you can show a rapid ROI. Eliminating energy-sapping compressors, pumps and other mechanical devices that also gobble up floorspace allows end users to do more in their existing facilities rather than trying to expand or find new real estate. Finally, implementing servo-electric technologies speeds up commissioning and greatly reduces support calls for the OEM and maintenance costs for the end user.
By taking a comprehensive view of energy-efficient motion control tech, machine builders and end users can find common ground. And as a result, the future of manufacturing starts to look greener, in more ways than one.
Want to enhance the drive technology in your industrial automation applications? Contact your local Beckhoff sales engineer today!
Matt Prellwitz is the Drive Technology Product Manager for Beckhoff Automation LLC.
A version of this article previously appeared in Control Engineering.
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