Metal Recycler Doubles Production and Eliminates Downtime with Medium Voltage VFD

Metal recyclers dread the call from their operator saying there’s another jam and they’re going to be behind on production – lost money, labor, time, and shipments behind schedule. Robertson Metal Recycling in North Dakota decided to change that status quo, installing a medium voltage VFD to run their shredder. With this setup, they doubled throughput, reduced energy demand and cost from the utility, virtually eliminated jams, and gave operators control they didn’t think was physically possible.

Battling Downtime, Fighting for Production

Blockages are the nightmare that keeps most metal recycling plants up at night. You can’t sell what you don’t process. The call that something jammed a shredder and needs to be removed is a moment that will make a plant manager’s heart drop. You could be lucky with just a couple of hours of downtime, but it could be bad enough that it takes an entire shift or more to cut out material and free up the shredder.

Blockages stop the entire plant. Operators scramble to clear the shredder, working long hours to get the system running again. The managers have to budget for this downtime without knowing when it will hit. Uncertainty ripples through every part of the business, from incoming scrap to labor scheduling, and even utility rates when they’re forced to make up production during high-demand hours.

It’s production living in limbo, with slow downtime and mad dashes to get back on track. That’s lost money bleeding out of your bottom line.

A Better Way to Shred

When Robertson Metal Recycling set out to install a new shredder system, they decided to break from the industry’s long-standing playbook. Instead of another wound-rotor motor and liquid rheostat setup, they turned to the VFDs.com team to see if a modern AC induction motor and medium-voltage VFD could handle the abuse.

Liquid rheostats have been the default system for decades because they are simple, reliable, and rugged. While early concerns about VFDs were once justified, that was 20 years ago. Modern medium voltage VFDs see a mean time between failures (MTBF) approaching two decades, running nonstop in the harshest conditions.

Daniel Robertson pulled the trigger on a 4000HP system, ordering an AC induction motor, VFD, and switchgear for his shredder, taking it to the cutting edge of the industry. He worked with the VFDs.com team to order, install, and commission the drive, taking into consideration the available power from the utility and the setup of the shredder they ordered.

The result was a system that did it all, including bringing in 12.47kV power from the utility and converting it to run a 6.6kV motor, all with the goal of maximizing his facility’s production.

Performance Beyond Belief

Over a year later, the results are still staggering:

• Throughput: 200% higher than expected (expected 60 tons/hour → achieved 120 tons/hour)
• Unplanned downtime: None, even after more than 12 months of operation
• Restart capability: Full-load restarts, no matter what was left in the shredder
• Material flow: No nuisance plugs, no matter the material
• Energy savings: Reduced energy required from the utility, leading to reduced electrical costs

“We can’t clog this thing,” Daniel said. “Other facilities have told us they have issues with chain link fences wrapping around their drum, but we’ve thrown it in and haven’t seen an issue. We even stop production for the day with trucks halfway through the shredder and it picks up the next day, no problem.”

When the VFDs.com team came out to site after six months of continuous operation, Daniel told us that they hadn’t had a single jam yet, even when they decided to push it to find out where the limit was.

“It bogs down when we overload it, slows way down. But it always comes back, gets through everything we throw at it.”

With the new system, Robertson Metal gained options they never had before. Fewer operating days, lower utility costs through off-peak scheduling, and total control over production pacing, allowing them to control their own future.

All of this was engineered by the VFDs.com team from specification through commissioning.

“This team’s been great to work with,” Daniel said. “We couldn’t have asked for more.”

Is a VFD Right for Your Shredder?

If every jam feels like money burning a hole in your pocket, it’s time to move into the modern era with an AC motor and VFD. Every day you wait is another day of lost production.

Talk to the team at VFDs.com to see how you can increase production, reduce downtime, and take full control of your shredder.