How a retrofit upgrade helped keep a leading steelwork running
A major global steel producer began experiencing problems with an overhead crane after the variable frequency drive (VFD) controlling its hoist motor became dysfunctional. However, the existing Yaskawa F7 drive installed on the crane had long since become obsolete, making a direct replacement impossible. As a result, the crane service provider responsible for the upgrade approached crane and hoist specialist CP Automation for support.
The overhead gantry crane played a key role in the steelworks, transporting large, high-temperature materials such as scrap metal and molten iron across different production stages. However, replacing the failed drive with modern hardware introduced several challenges, particularly as the installer was unfamiliar with the newer hardware platform and concerned about maintaining the crane’s existing performance characteristics.
Replacing obsolete hardware
After reviewing the crane drawings and existing control architecture, the team at CP Automation recommended upgrading the system using a CR700 crane drive, alongside a braking resistor and an encoder driver card for the VFD. The modernised setup also allowed the steel producer to remove several legacy components, including separate brake choppers and redundancy circuitry, from the system.
Unlike a like-for-like replacement, the retrofit required the crane’s original parameters to be translated from the obsolete F7 platform to the newer CR700 system. CP Automation extracted the parameter sets from the original drive and pre-programmed the replacement hardware before delivery, helping simplify installation and commissioning on the site.
“The customer initially approached us looking for a replacement F7 drive,” explained Ian Knight, Application Engineer – Cranes & Power Transmission at CP Automation. “Unfortunately, the F7 is now obsolete, so the only viable option was to move to a newer platform. Naturally, there were concerns about how the upgraded system would perform compared to the original hardware.
Designed for crane applications
As part of the retrofit, CP Automation specified a CR700 hoist drive platform designed specifically for crane and lifting applications. As well as replacing the obsolete hardware, the upgrade introduced several modern safety and performance features.
The replacement CR700 features a built-in brake chopper (up to and including 75kW), allowing several legacy components to be removed from the original system architecture while simplifying the wider control system. Meanwhile, integrated safety features such as safe torque off (STO) and dedicated Brake Sequence parameters (for controlling the mechanical brake) added another layer of operational protection. The platform also includes crane-specific functionality designed to support smoother load handling and improved control performance.
“The challenge with this project was ensuring the upgraded system delivered the same operational characteristics as the previous setup,” continued Knight. “By pre-programming the drive and supporting the installation team throughout commissioning, we were able to simplify the retrofit process significantly.”
Supporting installation and commissioning
Although the installer was experienced in crane servicing, the retrofit involved hardware with which it was unfamiliar. To help support the project, CP Automation worked alongside industrial engineering specialist BTC Citadel, which provided technical guidance and specialist training ahead of installation.
The training was crucial as it helped build confidence with the upgraded platform and ensured the installation team fully understood the commissioning process before arriving on site. The crane service provider ultimately completed the installation itself, while engineers from BTC Citadel provided additional technical oversight and support during commissioning.
“Ian delivered specialist training to help build confidence before the work began,” added Andy Swann, Global Business Manager – Cranes & Power Transmission at CP Automation. “That collaborative approach meant everybody involved understood the hardware and commissioning process before arriving on site.”
Since commissioning, the upgraded crane system has operated reliably, while also providing the steel producer with a clear pathway for future upgrades across other gantry cranes on site.
“Once the customer saw the results, they were very positive about the upgrade,” added Swann. “The project showed that older crane systems do not necessarily need to be replaced entirely. With the right expertise and modern drive technology, it is possible to extend equipment life, improve safety and simplify maintenance in a cost-effective way.”
To find out more about CP Automation’s crane retrofit support and how its range of AC/DC drives, magnetic controllers and other solutions can support, visit https://www.cpaltd.net/crane-ac-drives/
