Energy Saving options in automation

Performance benefits have been eagerly accepted by progressive machine builders who look to differentiate their products from competition – especially if these performance benefits are available on a cost neutral basis. Energy saving technology, in general, has not been adopted in the same way and remains to some extent underutilised by machine builders and manufacturers alike. So what are the benefits offered? and how can all users take advantage of the latest developments?

The area which has seen the most improvement in energy efficiency is probably motion control. If we consider that conventional drive systems convert only around half of the applied power from the mains into actual mechanical power, it is understandable why these products have been targeted so intensively.

The B&R ACOPOSmulti drive system is a good example of modern highly efficient technology, and offers energy savings through energy regeneration, true power factor correction, an intelligent cooling concept and a shared DC bus for all inverters

Active power supply modules are able to regenerate power back to the mains. Instead of being converted to heat as is generally the case, kinetic energy generated during braking is converted to electrical energy that is fed back into the power supply system. This has the additional advantage of eliminating the build-up of additional heat by braking resistors used inside the control cabinet, and is especially beneficial when several small axes have to be used in an extremely tight space. In these cases up to 30% of overall energy consumption can be regenerated.

PFC (power factor correction) in the ACOPSmulti ensures that the only power taken from the mains is effective power. This considerably reduces the connected load and current consumption of the machine – up to half in some cases; it also results in smaller fuses and wire cross sections.

The use of fans and climate control units in a control cabinet means considerably higher costs as well as additional maintenance expenses. ACOPOSmulti offers the machine builder ultimate freedom by opening up the free space required for either conventional heat dissipation inside the control cabinet, a feed-through cooler with IP65 protection for releasing heat outside the control cabinet or a cold plate variant that can be connected to a cooling circuit (water, oil).

On applications where some axis may be accelerating whilst others are braking, the shared DC bus ensures that energy can be redistributed automatically. This again offers the benefit of reduced energy consumption and, due to the fact that braking energy would have previously been converted to heat by braking resistors, further reductions in cabinet temperature and a reduced need for panel coolers.

One factor which must not be forgotten however is that the most technically advanced hardware cannot make up for inaccurately sized applications. B&R engineers use highly advanced simulation tools, combined with many years of application knowledge to ensure that the correct drives, motors and gearboxes are selected for customers’ machines.

One of the highest costs encountered in the running of a production facility is compressed air. It has been calculated that more than 10% of electricity supplied to industry is used to compress air, yet of the total energy supplied to a compressor, as little as 8– 10% may end up being converted into usable energy to power equipment, making it a highly inefficient and a costly energy source.


A considerably more efficient alternative to the pneumatic cylinder is a linear motor, which uses electromagnetic forces to convert electrical energy directly into movement. Like all electric motors, linear motors are extremely efficient by nature. This fundamental efficiency can be further increased using advanced drive technology such as the ACOPOS servo drives from B&R. These can additionally store braking energy in a DC bus circuit to be used for later acceleration. It is also relatively simple to return this excess energy back into the power grid.

"The potential for a real leap in energy savings was brought to our attention by a customer for whom we were calculating the energy consumption of our motors in comparison to a pneumatic system,” explains Ernst Blumer, head of sales at NTI AG, manufacturer of Lin-Mot linear motors. "This customer needed to move a 15 kilogram load a distance of 400mm at a rate of 30 cycles per minute. Our calculations showed a potential savings of over 90 percent, which was later confirmed by measurements on the actual system. In this particular application, the energy cost per axis was brought from 3,000 euros per year down to only 100.”

Replacing the pneumatic cylinder, which is similar in size and shape, can radically reduce the energy consumption of linear axes and provide an exceptionally fast return on investment. The reduction of CO2 emissions is also impressive. In three-shift production, the pneumatic axis in this application emits over 12 tons of CO2 – the equivalent of driving 100,000 kilometres with a modern midsized car.

Aligned with the options for improved efficiency, a clear understanding of the real energy consumed in production has become more and more important. Producers base their investment decisions in new equipment on hard facts with a clear return-on-investment scenario. That is why ROMI, the leading Brazilian plastics machine builder, has implemented a continuous energy analysis tool inside its standard machine control solution to allow continuous tracking of energy consumption in order to optimize production cycles.

"Producers have learned that the energy consumption has become an important factor in production costs, so they need to know real figures,” states Mr. William dos Reis, industrial director for plastic machines.

"We have been searching for an acceptable market price solution and have found it in the B&R X20 portfolio.” The X20AP3131 module is capable of calculating the effective, apparent and reactive power and energy and also calculates the RMS values automatically. "We have performed field tests with some key customers and have seen energy savings of up to 75 percent compared to machines installed 10 or more years ago,” explains dos Reis. This is a persuasive argument for producers facing investment decisions, with energy consumption playing a significant role in the ROI of a newly installed machine.

The market also offers solutions for machine builders and manufacturers to measure and/or control their energy. The APROL EnMon system from B&R provides continuous energy monitoring, either as a stand-alone unit or integrated in a process control system. APROL EnMon is a scalable out-of-the-box solution that is easy to integrate. It provides users comprehensive and intuitive support in the pursuit of optimizing energy consumption.  In the face of rising energy prices it is still possible to reduce unit costs while conserving valuable resources. B&R’s multi layered solutions can be implemented just as easily and effectively on the smallest stand-alone machine or at the most expansive processing plant.

For the companies who have not yet been convinced of the benefits of energy saving technologies and management, the introduction of The Energy Saving Opportunities Scheme (ESOS) is likely to force some companies to consider them. Despite some potential for increased "up-front” costs, considering the overall economic advantages, it must surely pay off to take a proactive approach and enjoy the competitive benefits of class leading energy efficient solutions in your machine or plant?