With the urgent need to replace fossil fuels, repeated shocks to the oil & gas supply chain, and technical advancements combined with lower costs for electrical systems, the drive toward electrification is transforming the way we live and work.
For many people, the electrification revolution is most evident in the proliferation of electric vehicles on the road. But the transformation may be even more dramatic in industries such as agriculture, mining, and the production of both traditional and renewable energy. For practically any industry that relies on linear motion, one of the best opportunities to take advantage of electrification is to replace hydraulic actuators with electric equivalents.
Electric linear actuation involves the conversion of rotary motion, produced by an electric motor, into linear motion, by means of ball screw, gear rack, conveyor belt or other transmission components. This technology can easily replace hydraulic systems that use a hydraulic power unit to pressurize oil, hoses and fittings to deliver the oil, valves to control the flow of oil, and hydraulic cylinders to contain the oil as pistons move the load in response to varying oil pressure.
The use of hydraulics to perform work goes back thousands of years, and the first hydraulic press — the prototype of today’s hydraulic actuators — was patented in 1795. These hydraulic systems have been proven to be effective and mostly reliable. That said, why would electric actuation be preferred, and why are so many industries making the conversion to electric?
Hydraulic power units require their own electric power. However, they are about half as efficient compared to electric linear actuators in converting electric power into physical work. Moreover, the hydraulic power unit must be running at all times to maintain pressure, while an electric motor draws little or no power when it is not moving. Many linear motion applications only move intermittently, so transitioning from hydraulic to electric can yield enormous savings in energy usage and costs.
Improved Control and Precision
Hydraulic actuators are incapable of finely tuned movement. The piston has a limited range of motion defined by the length of the cylinder, and variations in oil pressure and viscosity make ultra-precise positioning impossible. By contrast, a servo motor paired with a high-quality linear actuator is capable of extremely precise positioning, and the actuator can be virtually any length the application requires.
Minimizing Maintenance Issues While Increasing Reliability
Hydraulic systems incorporate many components that require maintenance and are subject to performance problems and outright failure. The hydraulic power unit is itself a complicated device, and then there are many additional components including the cylinder, control valves, oil filters, hoses, fittings and more — all potential sources of problems. Oil can get dirty, varying temperatures can affect its viscosity, and leaks are certain to occur. Maintaining these systems is expensive, and the cost of downtime when they fail can be devastating.
Electric motors and linear actuators, on the other hand, are relatively simple devices that require little maintenance. And they are vastly more reliable under a wide range of conditions — including temperature extremes, washdown scenarios, weather-exposed applications and hazardous atmospheres — when properly specified.
As mentioned, hydraulic power units are very inefficient in converting electrical energy into work. But that’s just the beginning. In outdoor applications, the power is typically supplied by a dirty, noisy diesel generator. The hydraulic power unit itself is also a major source of noise pollution. Of greatest environmental concern, virtually every hydraulic system ever created has leaked at some point — sometimes catastrophically. Leaks in an industrial environment can contaminate products and processes, while leaks outdoors harm communities, wildlife, water supplies and more.
Electric actuators are far more energy-efficient. In outdoor applications, they can use a smaller, quieter power supply or even run on batteries. Electric motors are very quiet, especially compared to hydraulic power units. And, of course, electric actuators don’t require pressurized fluids, so there’s nothing to leak.
Depending on the solution architecture, the initial cost of an electric actuation system can be more than a hydraulic system. However, the advantages of electric actuation in terms of substantially lower energy, maintenance, downtime and environmental cleanup costs make it the clear winner for long-term operational affordability.
Each hydraulic actuator is essentially its own, isolated system. Coordination of motion between multiple hydraulic systems can only be performed at a relatively crude level — not with the precision required for highly integrated industrial applications, autonomously controlled mobile systems, collaborative robots and other innovations that are changing the world today.
In addition, compressed air or hydraulic pumps are not always available in a particular setting, or desirable on a particular machine. In contrast, electric power is nearly always available to run the panel switches, sensors, displays, PLCs and other devices required for high-performance systems. It only makes sense to tap into the same power source to simplify your machine while enabling more precise, coordinated motion control. Electric motion — not hydraulic — is creating the future.
A Simple Transition to Electric Excellence
Wondering how electric motor control works, whether it’s right for your application and how to get started? Kollmorgen has the answers you seek, the motion technologies you need to achieve optimum performance, and the partners that can help you choose the right motion/actuator pairing for virtually any requirement.
We continually invest in research and development to enhance our motor, drive and control designs for increased power, torque density and ease of use. For example, we have developed specialized motor windings and use advanced permanent magnet materials to deliver maximum torque in the most compact form factor while minimizing energy consumption.
A Kollmorgen specialty is working directly with customers to understand their application requirements and collaboratively engineer an optimum solution. For example, read how our motion experts have helped the oil industry transition from hydraulic to electric in some of the most challenging applications, including remotely operated vehicles, subsea operations and downhole tooling. Also, be sure to check out our online, self-service Motioneering tool for simple sizing of motors to work with linear actuators such as ball screw, gear rack and conveyor belt designs.
We can also guide you to the right partner to pair your Kollmorgen motor and drive with the optimum linear actuator for your application needs. It all begins with an exploration of what those needs are. Contact us today and let’s talk, engineer-to-engineer, about how to make the transition from old-fashioned hydraulic systems to your future of simpler, more precise and efficient, environmentally clean electric actuation.