Protecting VFD Driven Motors in Steel Mills

VFDs Improve Process Control and Reduce Energy Costs

According to the American Iron and Steel Institute, the cost of energy makes up 20% of the total cost of steel production. So by reducing energy consumption, plants can increase profitability.

Steel MakingBy allowing precise control of motor speed, variable frequency drives (VFDs) not only reduce energy costs by 30% or more, they improve process control, reduce waste/spoilage, and help improve product quality.

But VFDs Can Damage Motor Bearings and Shut Down Processes...

But, VFDs can damage motors. They induce voltages on the shafts of the motor they control — voltages that can discharge through motor bearings, causing fluting and catastrophic motor failure.

And the Cost of Downtime is Staggering

Steelmaking is a continuous process, so a problem in one part of a production process or even a single piece of equipment can idle an entire plant. And the cost of such shutdowns can be staggering — from $200,000 to $600,000 per day or more, depending on the production capacity of the plant.

Protect VFD-Driven Motors From Bearing Damage With AEGIS® Shaft Grounding Rings

By diverting damaging bearing currents safely to ground, AEGIS Shaft Grounding Rings ensure the reliable, long-term operation of VFD-driven steel mill motors and systems.

So, to prevent VFD-induced bearing damage and costly, unnecessary downtime and repairs, specify/install AEGIS Shaft Grounding Rings on all AC and DC motors. Designed to withstand the harsh conditions of steel mills, they can be installed on:

  • New motors before they are put into service
  • In-service motors when they are refurbished or repaired
  • Spare motors when they are purchased or before they are put into service

Unlike other shaft grounding products, AEGIS Rings do not require routine maintenance or adjustment. They provide effective protection for the L10 life of the motor bearings.


AEGIS Rings also come with a 2-year extended warranty against bearing fluting damage. No other form of protection against VFD-caused bearing damage offers a warranty like this.

2-Year Extended Warranty

To learn more about AEGIS shaft grounding and best practices for electrical bearing protection, sign up for a training. We offer monthly live training webinars, and - pandemic restrictions permitting - we can also visit your facility to review your exact application.

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