As a leader in the high efficiency electrical transformer core market, it’s safe to say that we here at Corefficient know a thing or two about how to create a reliable end product. In past blog posts, we’ve covered the interesting history behind the electrical transformer core, and this week, we’re going to cover how an electrical transformer core is made; the Coreffiicent way.
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STEP 1: The Material
Before one can even begin the electrical transformer core construction process, you need to make sure that you’re using the best materials available. The material of choice for electrical transformer core companies is cold rolled grain oriented electrical steel, and Corefficient is no exception.
Corefficient has extensive on-site testing capabilities to ensure that the material we receive from our suppliers has exceptional magnetic flux and permeability properties. Why go through the trouble? It’s simple – the better the material, the easier it will be for the magnetic field of the core to flow. Also, high quality cold rolled grain oriented electrical steel reduces losses by reducing the strength of the eddy current.
STEP 2: Material Prep
Now that we’ve ascertained that we’re working with superior quality material, it’s time to cut the material for construction. For our Step Lap Full MITRE Cores, we make use of top of the line GEORG brand TBA lines for the cutting of electrical steel. For our wound cores, we use our highly versatile TRANCO and AEM machines, allowing us to work closely with our customers and their unique specifications for their core. These fully automated precision cutting lines allow us to complete our construction process with incredible speed.
STEP 3: Assembly
Next stop on the assembly line, we stack the core using our fully automated machine. Within 15-20 minutes, we have full stacks of electrical steel that are ready to be shipped as logs, or further assembled into fully functional transformers. With our Step Lap Full MITRE Cores, they’re moved down the assembly line, where our team performs a series of tests and quality checks including testing on a Yokogawa precision power analyzer.
For our DISTRIBUTED GAP Cores, we offer core annealing services, where we utilize our continuously fed SECO/WARWICK annealing furnace first, through annealing, the transformer cores’ magnetic properties are restored. Second, our core annealing services strive to reduce carbon levels within electrical steel to levels less than .01%. Our core annealing process is proven to increase strength, formability and elasticity to the electrical transformer core.
Step 4: Delivery
Finally, once your core is complete to your specifications, we ship it off. Corefficient is proud of our 100% SOT (Ship on Time) record, and our customers receive their finished core within two weeks of completion.
In transformer core manufacturing, efficiency gains in production cannot sacrifice part accuracy. Micro Tool & Machine Ltd. (MTM) made repeatability its top priority while working to increase throughput of its X-Shear machine. “Higher production rates are the goal of every machine manufacturer,” says Gord Atamanchuk, General Manager of MTM. “Doing this without sacrificing processed part accuracy is critical to our success. Once processed, being able to assemble those parts into the final e-stacked core, while minimizing gaps, is more critical than ever due to the industry trends to reduce post-processing time downstream.”
Based in Winnipeg, Manitoba, MTM provides machine solutions for the manufacturing and distribution of medium-size power transformers, along with aerospace, medical and other industries. MTM designs and manufactures complete systems that integrate CNC, robotics, tooling, assembly, jigs and fixtures. Since its founding in , the company has offered high degrees of customization to accommodate the unique process flows or facility layouts of its global customers. The engineering team often reevaluates technologies and components to provide the most robust capabilities, as the recent X-Shear redesign proves.
The XS600-P20E X-Shear cuts, stacks and assembles transformer laminations using PC-based automation and robotics. At one end, the machine uses an X-shaped blade configuration to cut any required geometry from coiled lamination of varying widths. After that, two articulated KUKA robots in conjunction with two pick and place arms assemble the core pieces. The system is designed to cut and assemble up to four transformer cores at once in e-stacking modes and sort the cut laminations into 30 segment piles when not in e-stacking modes. However, it can scale up or down depending on product sizes, according to Eduard Streichert, Electrical Lead at MTM. “Using what we learned from previous machines, we made several upgrades for this new X-Shear,” he says. “The biggest upgrade was the conversion to the Beckhoff control system.”
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At 13 meters (43 feet) long by 8 meters (26 feet) wide, the X-Shear’s footprint already measured up to three times smaller than many competitors, according to Atamanchuk. “Our integrated method for loading and unloading reduces the size of the machine. Most other machines stack segment piles in a linear fashion, while we use a space-saving grid format,” he says. In the redesign, MTM engineers focused on optimizing throughput, increasing cut accuracy and reducing component and labor costs. MTM wanted to reduce wiring effort with distributed I/O modules. The X-Shear needed to leverage IoT-ready technologies to offer the customer opportunities to further enhance machine performance and to provide remote support, since the machine would eventually be installed in China. It also needed to shorten PLC cycles and scan times.
“One of the biggest keys was implementing a true multitasking controller. The previous control platform we used fell short of our runtime requirements. The system had limited capability to perform conditions or commands in parallel. This meant fewer parts per minute,” Streichert explains. “Switching to a standardized PLC program – specifically IEC -3 – would provide further gains. For electrical technicians, it’s easier to troubleshoot in standard PLC languages.”
MTM engineers combined what they had learned from previous systems and customer feedback, then leveraged a new control platform for the X-Shear. In the five years leading up to this redesign, the engineering team had transitioned all other machines to PC-based control from Beckhoff Automation. Now, they were ready to update the largest and most complex machine. “MTM is always interested in implementing the latest and greatest technologies from Beckhoff,” says Amir Kassaian, Regional Sales Engineer for Beckhoff Canada. “The X-Shear redesign offers a testament of how Beckhoff minimizes the learning curve for OEMs that want to modernize their controls and networking platform.”
MTM found the multitasking control system needed to enhance the X-Shear in TwinCAT 3 automation software and the C control cabinet Industrial PC (IPC) from Beckhoff. The multiple runtimes in TwinCAT enable deterministic control for parallel tasks, including high-velocity coordinated motion used with the X-shaped cutters. Through Visual Studio® integration, TwinCAT enables programmers to use the best language for the project and the engineer, including IEC -3 and its object-oriented extensions, predefined or custom function blocks and computer science programming standards. Streichert found this very beneficial: “Unlike the previous programming platform, TwinCAT helps technicians see potential issues faster and understand how to fix them.”
The C control cabinet IPC boasts a seventh-generation Intel® Core™ i5 processor with four cores and a 2.7-GHz clock speed. The single PC-based controller handles control logic, IoT connectivity and other functionality for the cutting and stacking cells. “As a true multitasking controller, the C reduces machine cycle times so that throughput is much higher,” Streichert says. “The IPC offers one combined solution for PC and PLC technologies. This includes everything from connecting to higher-level systems and enabling remote support to storing recipes and running the HMI in Visual Basic.”
For operator interface, MTM selected a CP multi-touch Control Panel with custom push-button extensions. This IP65-rated, 21-inch touchscreen is pole-mounted on the cutting cell. The stacking cell features a built-in CP multi-touch Control Panel, which provides the same HMI experience scaled to a 12-inch touchscreen. “Beyond standard machine control, operators can use these touchscreens to enter different core files or for recipe management,” Atamanchuk says. “This was also the first time we used CP-Link 4, which helped reduce cabling requirements.” CP-Link 4, the One Cable Display Link, supplies power, USB 2.0 and DVI signals to control panels in a single cable up to 100 meters from the controller.
For Beckhoff Applications Specialist Chris Timmermans, upgrades in motion control and networking were among the most important aspects in the X-Shear project. “MTM shifted fully to the Beckhoff platform by implementing AX Servo Drives and AM Servomotors, along with various gearboxes for the cutting axes. The EL EtherCAT Terminal for servomotor control also offered a compact motion solution with a high RPM, and its 24-mm-wide, DIN rail-mounted I/O form factor saved space in the electrical cabinet,” Timmermans says. The fully integrated Beckhoff ecosystem enables motion design tools, real-time PLC and a digital oscilloscope all inside the standard TwinCAT software. This helped with fine-tuning movements for highest accuracy, Streichert explains: “When tuning motors on the X-Shear, we use TwinCAT Scope View and really push the system to its highest performance.”
The EtherCAT industrial Ethernet system delivers fast communication, flexibility and a range of hardware solutions. EL series EtherCAT Terminals comprise the main I/O in the control cabinet, and IP67-rated EtherCAT Box modules distribute intelligence across the machine. TwinSAFE Boxes and Terminals also offer TÜV-certified functional safety with programming in TwinCAT and communication over the standard network. Without hardwiring of black-box safety switches, MTM connected all E-stops, light curtains and safety gates on this model, and the modular design allows end users to tie in additional safety devices to the system as desired.
“The integrated architecture offered many advantages in terms of both commissioning and performance,” Streichert explains. “Along with CP-Link 4, the EtherCAT and TwinSAFE solutions greatly reduced cabling and wiring effort. The EP Boxes allow the controller to capture signals from sensors, along with hydraulic and pneumatic devices, spread throughout the X-Shear. As a result, we increased performance while reducing expenses.”
By transitioning to the Beckhoff platform, MTM boosted performance and functionality for the XS600-P20E X-Shear. The machine increased its maximum cutting speed to 34 sheets per minute – a 55% increase in speed compared to previous models with the legacy PLC. These gains resulted in part from significantly faster PLC cycle time of 1 ms. Beyond reducing cabling, control cabinet requirements and costs for the related components, the Beckhoff engineers also helped MTM optimize servomotor sizing, allowing them to scale down and reduce expenses compared to the previous solution while still boosting overall performance.
Most importantly, the X-Shear redesign accomplished its key goal – maintaining high cut accuracy. “All of these improvements are very important and make our machine stand out to customers when compared to others on the market,” Atamanchuk says. “The Beckhoff platform’s scalability will also allow us to make upgrades and increase functionality on the X-Shear and our other machines.”
Since transitioning to Beckhoff, MTM has completed nearly 30 projects using PC-based automation. The robust and reliable components have allowed the company to focus on other business and technology aspects, according to Atamanchuk: “We've been able to standardize our HMI layouts to present information more clearly and still insert system-specific pages, and we plan to implement this with TwinCAT HMI very soon. With Beckhoff, we have access to IoT-ready components from one manufacturer, making it easier to roll out new features to customers, which was more challenging in the past.”
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