In manufacturing, unplanned downtime costs are huge and only getting more significant. According to a recent study of 72 large companies by Senseye Predictive Maintenance, large plants' costs of unplanned downtime average $532,000 per hour. The study cites the disturbing figure that downtime costs these companies 11% of their annual revenue in 2022, up from 8% in 2020.
What Are Manufacturers Doing to Mitigate Unexpected Downtime?
It goes without saying that manufacturers do all they can to minimize unplanned downtime. There are many components to a downtime mitigation strategy, ranging from beefing up maintenance programs to investing in protective products to make manufacturing systems as reliable as possible.
Protecting Motor Bearings From Damage by VFDs
One step in this direction is to protect electric motor bearings against the damage caused by variable frequency drive (VFD) control. VFDs generate high-frequency voltage on the shafts of the motors they control. Without protection, this so-called shaft voltage will discharge through the motor or system bearings, causing electrical damage, eventual premature failure, and potentially unplanned downtime.
A Reliable Strategy: Shaft Grounding Ring
One protective product is the AEGIS® Shaft Grounding Ring. AEGIS rings provide a low resistance path to charge on the shaft and bleed down the shaft voltage to levels too low to arc through the bearings, protecting them from discharge damage. When protected by AEGIS rings, VFD-controlled systems are less likely to fail prematurely, and one risk of unplanned downtime is thus mitigated.
While AEGIS rings alone cannot prevent every motor failure, they are an important part of the overall reliability strategy for every plant that uses VFDs for motor control.
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.
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.
FAQ
Q1. What are other causes of unplanned downtime, not involving VFDs?
A1. Not all bearing failure is caused by VFDs. Contamination (in unsealed bearings) is a common cause of failure. Other system components can also fail. Often, the cause is human error - misalignment of components, errors in control programming, and failure to notice or respond to small problems that spiral. Supply chain disruptions and unpredictable events like power outages and extreme weather also contribute to unplanned downtime. The key to minimizing unplanned downtime is to focus on what can be predicted or protected against.
Q2. How effective at preventing bearing failure are AEGIS rings?
A2. When installed properly, AEGIS rings effectively lower shaft voltage, protecting against bearing failure due to electrical damage, and reducing the total risk of unplanned downtime. However, they do not protect against circulating bearing current in larger motors (over 100 hp/75 kW) - For circulating current, you need either bearing insulation or VFD output filters to mitigate damage. And AEGIS rings - or any electrical bearing protection - cannot prevent bearing failure due to non-electrical damage like excessive vibration from misalignment.
Q3. What other strategies or protective measures besides AEGIS rings can manufacturing plants employ to mitigate the risk of unplanned downtime related to VFD-controlled systems?
A3. Besides AEGIS rings, other protective measures may include: regular equipment inspections and maintenance, implementing condition monitoring and predictive maintenance programs, investing in high-quality VFDs with built-in protective features, using proper grounding and bonding techniques, and providing comprehensive training for operators and maintenance staff to ensure proper handling and troubleshooting of VFD-related issues. Combining multiple layers of protection and proactive maintenance practices enhances the reliability and resilience of manufacturing systems against unplanned downtime.
