We’ve been in this business for over 35 years now, and if we had a dollar for every time someone called us in a panic because their medium voltage drive just went down unexpectedly, well… we’d have a lot of dollars.
The conversation usually goes something like this: “Trey our drive just died. We need you here YESTERDAY. Production is down, and this is costing us a fortune.”
My first questions are always the same: “Do you have spare parts?” and “When was the last time you did preventative maintenance on it?”
The answer? Often crickets. Or “Um, I’m not sure.” Or my personal favorite: “We were planning to do that next month.”
Look, I get it. When a drive is running fine, it’s easy to push maintenance down the priority list. There’s always something else that seems more urgent. A PM on a drive that’s working perfectly feels like spending money on a problem you don’t have.
But here’s the thing: you DO have a problem. You just don’t know it yet.
The Real Math Nobody Wants to Do (But Should)
Let me paint you a picture with actual numbers.
Scenario A: The “We’ll Deal With It When It Breaks” Approach
A cement plant in the Southeast had a 2000 HP Medium Voltage Variable Frequency Drive running a critical fan. They kept putting off maintenance because, hey, it was running fine. Until it wasn’t.
On a Thursday morning, the drive went down. Here’s what happened:
- Production loss: 36 hours of downtime at $50,000/hour = $1,800,000
- Emergency service call: Including weekend overtime rates = $15,000
- Damaged components: Power cells failed = $80,000
- Expedited parts shipping: Expedited repair and shipping = $25,000
- Total cost: $1,920,000
And that’s not counting the stress, the scrambling, the angry calls from upper management, or the customers they couldn’t deliver to on time.
Scenario B: The “Boring But Smart” Approach
A similar facility scheduled yearly preventative maintenance with us. During a routine inspection, we found:
- Capacitors showing signs of degradation
- Cooling fans with failing bearings
- Minor contamination buildup on heat sinks
- A few loose power connections
We scheduled a planned shutdown, replaced the at-risk components, cleaned everything up, and had them back online in 2 days during their normal maintenance window.
Their cost:
- Planned downtime: 16 hours at $50,000/hour = $800,000
- Preventative maintenance service: $12,000
- Replacement parts: $35,000
- Total cost: $847,000
That’s a $1,073,000 difference.
The Small Problems That Become Big Problems
After three and a half decades of working on Variable Frequency Drives, we can tell you exactly what happens when maintenance gets deferred. These issues don’t happen overnight; they tend to happen slowly over time
Electrolytic Capacitors: The Ticking Time Bomb
This is the big one. Electrolytic capacitors have a useable life of about 7-10 years. Period. It’s not a matter of IF they’ll fail—it’s WHEN.
What happens when they start to go? As capacitors lose their ability to smooth and store DC charge, the ripple increases. As ripple increases, the capacitor degrades.
Then one day—BOOM. The capacitor fails catastrophically. And when it goes, it rarely goes alone. We’ve seen failed capacitors take out:
- IGBTs (those aren’t cheap)
- Driver boards
- Bus bars
- Even the chassis itself in extreme cases
Cooling System Degradation
Heat is the enemy of electronics. Always has been, always will be.
When cooling fans start to fail (and they do—they have bearings, and bearings wear out), the drive runs hotter. Hotter components age faster.
We’ve seen drives where contamination buildup on heat sinks reduced cooling efficiency and although the drive kept running, it was slowly cooking itself from the inside out.
The Loose Connection That Shouldn’t Be Loose
This one drives me crazy because it’s so preventable.
Connections loosen over time due to thermal cycling—the heating and cooling that happens during normal operation. A loose connection creates resistance. Resistance creates heat. Heat creates more resistance. It’s a vicious cycle.
Contamination: The Silent Killer
Depending on your environment, drives can accumulate dust, moisture, chemicals, or other contaminants. A little bit? Not a big deal. But over months and years, it builds up.
We’ve seen:
- Conductive dust creating tracking paths between components
- Moisture causing corrosion on circuit boards
- Chemical contamination degrading insulation
- Debris blocking cooling airflow
All of this is easy to clean during planned maintenance. All of this causes catastrophic failures if left unchecked.
The Real ROI of Preventative Maintenance
Here’s what nobody tells you in the equipment manual: the cost of maintaining your drive is built into the total cost of ownership whether you like it or not.
You’re going to pay. The only question is: Do you want to pay on YOUR schedule or the drive’s schedule?
Let’s look at a typical medium voltage drive over a 15-year lifespan:
The Proactive Plant:
- Annual PM visits: 15 visits × $12,000 = $180,000
- Scheduled capacitor replacement (year 7): $50,000
- Minor repairs and updates: $25,000
- Total 15-year cost: $255,000
- Unplanned downtime: 0 hours
The Reactive Plant:
- No scheduled PM: $0 (initially)
- Three major unplanned failures over 15 years: $3,500,000 (downtime + repairs)
- Emergency service calls: $45,000
- Expedited parts shipping: $60,000
- Total 15-year cost: $3,605,000
- Unplanned downtime: 120+ hours
I know which one I’d choose.
The “We Can’t Afford Downtime” Paradox
Here’s the irony: The facilities that tell us they can’t afford scheduled downtime for PM are the same ones that end up with 36-hour unplanned outages.
If you truly can’t afford downtime, you REALLY can’t afford to skip maintenance.
The Bottom Line
I’m not trying to scare you (okay, maybe a little). But after 35 years in this industry, we’ve seen the same story play out hundreds of times.
Deferred maintenance isn’t “saving money.” It’s just moving costs around—and usually multiplying them by 10 or 20 in the process.
The drives we see that run for 15, 20, even 25 years with minimal issues? They all have one thing in common: regular, scheduled preventative maintenance.
The drives that fail catastrophically and expensively? They’re the ones that got neglected.
Let’s Talk About Your Drives
If you’re running medium voltage VFDs and you’re not on a regular PM schedule, let’s change that.
At EMA, we’ve been servicing drives longer than most of our competitors have been in business. We know every topology, every common failure, every trick for extending equipment life.
No One Anywhere Knows More About Medium Voltage Drives Than We Do.
We can develop a PM schedule that works for YOUR facility, YOUR budget, and YOUR operational constraints. Give us a call at 770-448-4644, shoot us an email at info@emainc.net, or use the chat feature on our website. Let’s talk about keeping your drives running instead of scrambling when they don’t.
Your future self will thank you. Trust me on this one.