Variable-speed pump drives can provide exponential energy savings, noise reduction and predictive maintenance for hydraulic presses and other large machines.
Machine energy saving insights
- Understand how variable speed pump drives use real-time data to improve machine uptime, precision, and predictive maintenance.
- Identify how variable speed drives amplify energy savings, reduce noise and cooling demand by matching motor speed to actual machine needs
- Learn how integrated variable speed drives are becoming more practical for industrial automation as hybrid architectures become the default for hydraulic applications.
Improved access to data has drastically changed the way industrial automation experts are approaching operations with hydraulic components. Factories have long relied on analog machines with basic digital controls that are now being phased out to make way for advanced control systems.
Today, information between machines and industrial hydraulic components is being communicated and analyzed using fieldbus systems with high-precision sensors alongside emerging technologies like AI. This integration of advanced technology has become the key for facilities to increase machine uptime, performance and energy efficiency.
Variable-speed pump drives (VSDs) are components that control electric motors and aid in energy savings and noise reduction. In fact, retrofitting hydraulic presses with variable-speed pump drives has been proven to cut energy use by up to 80% and reduce noise up to 20 decibels. This technology also greatly improves operational energy efficiency due to the drives’ ability to switch to standby in idle phases, which also reduces the need for cooling.
As adoption of variable speed technology grows, hybrid architectures will be the default for hydraulic applications in the industrial automation industry. This allows for the best of both worlds: marrying a proven reliable technology of hydraulics with the brains and controllability of a VSD.
Machine integration, digital advantages
When digitally integrated, real-time monitoring of systems through sensors and bus systems offers diagnostic capabilities that help reduce unnecessary downtime and improve machine precision. This is especially impactful for large machines like hydraulic presses that move quickly and require high peak power but can maintain consumption without sacrificing performance.
Advanced VSDs are a part of the next phase of the Industry 4.0 revolution centered around data. Engineers can access on-demand data and information from these essential hydraulic components to better assess wear and tear and other machine working conditions to provide real guidance for improved operational efficiency.
Modern VSDs feature open communication interfaces to integrate condition monitoring and diagnostics that impact how quickly or cohesively data is analyzed. Predictive maintenance monitors aspects of performance such as torque, current and output pressure to predict potential failures, streamlining machine operators’ ability to respond to data and act quickly.
Operators can better understand how a system is behaving when using real-time data connected to their programmable logic controller (PLC) with communications such as Ethernet, Profinet or EtherCAT, to constantly monitor a system’s torque, current and pump output pressure. In addition to simplified data analyzation, these integration capabilities unlock measurable energy savings for operators.
Energy efficiency: Adjust pump speed to supply necessary power
When machines operate at peak efficiency, facilities develop a smaller footprint in response. As industrial hydraulics components continue to improve, machine operations will utilize much less energy with a simple component switch that reduces pump speed to only use necessary power. Variable speed drives allow motor speed to be controlled instead of being kept at a constant speed to match the flow, avoiding losses and reducing power consumption. This also allows the work cycle to avoid overuse and unnecessary emissions.
In addition to these cumulative savings, the space needed is drastically reduced through variability. Less hydraulic fluid is needed, allowing it to be contained in smaller reservoirs, and the temperature reduction from a lower average pump drive speed also requires less space previously needed for cooling large head loads. Despite these clear advantages, lingering misconceptions about this technology still need to be overcome to enable more robust implementation.
An example of this technology at work would be in a pressing application that requires the pressing of the part a few times an hour. In this application, the hydraulics would ramp up to meet the maximum speed of the press. Once the press contacts the part, it will slow down and hold tonnage for a predetermined amount of time until the part is finished curing.
If there is no VSD in the application, the motor will continue to spin at the nameplate speed even though there is a low flow requirement. However, if there is a VSD the motor would be slowed down during the curing time since maximum speed is no longer required from the motor to perform the work. This slowing down of the motor can save a significant amount for curing times that take up much of the machine cycle along with less strain on the system.
Barriers to adoption of variable-speed drives
Implementation of variable-speed drive technology has, luckily, become easier in recent years as costs have decreased significantly. In hydraulic applications, when the goal is to reduce the amount of starting current on a motor, soft starters would be used due to the large current spikes that hydraulics can cause from the large moment of inertia. Now, VSDs can be nearly the same cost as soft starters, allowing operators to reap the benefits without going over budget. This has lowered the barrier of entry to implement VSD with hydraulics even if the duty cycles are efficient.
Common misconceptions or outdated understandings of hydraulics have hindered adoption of this technology as well, specifically when it comes to noise. When variable-speed drives are utilized, the system runs much quieter than it used to due to the on-demand power. Whenever a cycle requires pressure or flow, the machine is better able to slow down and idle, decreasing the loud humming associated with large hydraulic systems.
Lastly, the expertise and knowledge required for personnel to operate traditional industrial machinery is becoming more niche. By incorporating VSDs—especially ones with hydraulic intelligence built on-board—machine operation is greatly simplified. For example, if a machine operator were trying to control the pressure on a cylinder, they would typically need a motor, pump, a manifold with a proportional valve, and other supporting valving.
With a VSD, these functions can be replicated. Instead of using the valve, the pump can be utilized to control the pressure on the cylinder. This makes the overall machine smaller, easier to maintain and simpler to operate. Simplifying how hydraulic machines function allows a more sustainable way to use this technology with a quickly changing workforce skillset.
Future of industrial automation, hydraulic advantages
Hydraulics are not going away any time soon. While electrification is a hot-button topic, hydraulics will remain essential for applications requiring extreme force, speed or repeatability. While industrial hydraulics have somewhat fallen behind the curve of advancement due to their more primitive technology, they still maintain their function and are overwhelmingly useful for speed, force and repeatability. This is why total electrification of hydraulics is difficult, giving hybridization the best path forward.
Hybrid hydraulics and electric systems are very likely to continue to be adopted to prioritize energy efficiency and give operators more insight into machines’ inner workings to make informed decisions. The benefits of variable-speed drives in industrial spaces outweigh the upfront costs, especially through helping to make factory floors less noisy and deliver overall cost savings.
Christopher Parisse is senior controls product engineer – Bosch Rexroth. Edited by Mark T. Hoske, editor-in-chief, Control Engineering, WTWH Media, [email protected].
Keywords
Variable-speed drives, motor-drive efficiency, industrial energy efficiency
Consider this
Machine design or retrofits that integrate variable-speed pumps for hydraulics save energy and money while reducing downtime and noise.
You also might like
Find more from Control Engineering on motion control and motors and drives.
