Published

3 weeks ago

July 16, 2026

Alice Rush

Weather Guard Lightning Tech

Malloy Wind and NSK on Main Bearing Failures

Cory Mittleider of Malloy Wind and Loren Walton of NSK on main bearing failures, why the industry is pulling DLC coatings, and the material changes replacing them.

Sign up now for Uptime Tech News, our weekly newsletter on all things wind technology. This episode is sponsored by Weather Guard Lightning Tech. Learn more about Weather Guard’s StrikeTape Wind Turbine LPS retrofit. Follow the show on YouTube, Linkedin and visit Weather Guard on the web. And subscribe to Rosemary’s “Engineering with Rosie” YouTube channel here. Have a question we can answer on the show? Email us!

Allen Hall: Cory and Loren, welcome back to the podcast.

Cory Mittleider: Thanks for having us.

Allen Hall: So we’ve got two bearing experts in one location, and this is the point where we start asking all of our bearing questions. Cory, you’re with Malloy Wind, and we’ve had you on the podcast two or three different times. Loren’s with NSK — we’ve had Loren on at least once before.

Loren Walton: Once, yes.

Allen Hall: Yeah, and that was good.

Loren Walton: I appreciate that. It was fun.

Allen Hall: There are a lot of bearing issues happening in the States at the moment, but also globally. Whatever happens in the States, you can pretty much find in Australia, Canada, Singapore, Mexico, South America, Brazil — everywhere. We’re hearing a lot about main bearings, and there’s a variety of things that I think you two know from being on the inside that we on the outside haven’t heard yet. I want to get some of those stories out and understand what’s going on, because operators are trying to keep their assets running, and bearings are a big issue. Let’s talk main bearings. What are you seeing in the field right now? What kinds of problems are happening?

Cory Mittleider: It seems like operators are coming to us and asking us to supply bearings that no longer have DLC. That’s a bit of a phenomenon lately. For a little over a decade we spent our time supplying bearings with DLC on the rollers to address problems found fifteen years ago.

Allen Hall: DLC is diamond-like coating.

Cory Mittleider: Correct.

Allen Hall: Which is a really hard specialty coating applied to the bearing surfaces to provide hardness and durability — or it’s supposed to provide durability.

Cory Mittleider: That’s a good point. It’s a coating that’s one to two microns thick — one to two thousandths of a millimeter — and a very hard material. The big feature was that it’s a dissimilar material to the steel. So when we break through the mixed and boundary lubrication regimes and those asperities touch each other, that dissimilar material prevents the welding and tearing that leads to the peeling damage we saw fifteen years ago. That peeling damage eventually turned into spalling, cracking, and other failures. So it made a lot of sense at the time to turn to something like this to mitigate the peeling.

Allen Hall: So the peeling damage was one of those issues where you basically had some sliding happening. In my electrical world, and from looking at these on the ground, you see things moving relative to one another instead of rolling relative to one another.

Loren Walton: It’s more of a welding and shearing of the contacts. I used a finger analogy last time: think of your asperities as fingers — one set is the roller, one set is the outer raceway. They weld under high load and high pressure, then they shear, leaving behind debris. That’s what creates the beginning of the peeling damage, and then it continues to create more debris, and the bearing starts to basically eat itself alive.

Allen Hall: The start of that process, though — is that a lack of lubrication, or a finish or hardness issue on the bearing?

Loren Walton: I love that question, because this is the crux of the whole thing, and I think it’s the part that gets missed. People immediately want to throw the whole thing out and start over with something different. Fundamentally, when we fixed the surface issue by adding the coating, the problems pretty much went away. We went from one-to-five years of life to ten-plus years, depending on the application — without changing the construction, the bearing type, or the contact angle. Just by adding the coating, we increased life significantly. The root of what you’re asking is that the bearing would operate better if it had the proper amount of separation. It’s not a fatigue issue and it’s not a loading issue. At its heart, the bearing isn’t able to create that separation. There isn’t enough speed, and there isn’t enough of a gap created by the lubricant.

Allen Hall: So ideally you have this almost molecular-scale film of lubricant between the two surfaces. If it isn’t designed properly, or you have an issue, that lubricant gets squeezed out of the space, and at that point you have trouble. That’s some of what I’m hearing on main bearings — especially when turbines have been curtailed and aren’t turning. Is that partly just the fact that there’s so much load?

Cory Mittleider: I think that’s a fundamental difficulty of the main shaft bearing. You’ve got extremely variable loads, from full load to idle, and a wide range of operating conditions — from northern North Dakota in the winter to Texas in the heat this week. High load, heavy load, incredibly slow speed, and even slower if it’s idling. It’s hard to reliably build that film. It’s not necessarily that there isn’t enough lubrication; it’s that the film isn’t building properly where it needs to be to separate the metal and the rolling elements.

Allen Hall: So the diamond-like coating was meant to solve that welding problem — you put the coated bearing in, and it worked okay until more recently, when all of a sudden we started having other issues. To me those aren’t related to the coating itself, but to other things happening up in the nacelle.

Loren Walton: If we recall some of your previous episodes, you were on the forefront of understanding and talking about DLC starting to become an accelerant to failure. I know you talked about it with Cory. Those episodes have aged very well. A lot of people now are recognizing what we were saying years ago and changing their strategy toward removing DLC — whether on bearings for newer turbines, typically two megawatts and greater, or in some cases going backwards and removing DLC as they do additional replacements, and looking for another solution, because there’s potential for additional issues you weren’t expecting by adding the coating.

Allen Hall: The coating is non-conductive, which is part of the issue, because you wouldn’t think bearings are conducting electricity. But as turbines got some of these uptower and downtower converters and inverters connected to the generator, we started seeing current levels — according to Motor Doc, where people like Howard Penrose have gone out and measured currents in the nacelles — of well over a hundred amps running through ground straps and the like, into bearings. That’s a lot of current. If you’re shoving that into a bearing that has DLC on it, you’re going to break it down and create these really hard steel bits stuck inside the bearing, which wear it like pouring sand inside a bearing. That’s what eventually happens, and it has nothing to do with the bearing. It has more to do with the electrical and control systems we stuck up top and didn’t pay much attention to, but probably should have. We created an electrical situation, and now all the upkeep comes to people like you to deal with. You haven’t seen a lot of work to eliminate it, although there are a couple of good attempts happening. The reality is: okay, we have to have a bearing, and I’ve got this current going around from the nacelle. How do I put those together in a way that removes the DLC?

Cory Mittleider: That’s what we’ve spent the last ten-plus years on. As a bearing supplier, we can’t change the whole system. We have to do the best we can to accommodate what’s happening in your system. We would absolutely encourage you, if you can identify and remove the electricity, please do that.

Allen Hall: They should. And there are a lot of people who do.

Cory Mittleider: There’s a pursuit of that, absolutely. But the turbine still needs to run.

Loren Walton: We work very closely with an owner-operator that did a lot of that work. To your point from before, it does sound like, from what they’ve investigated, the current has been there for a while. It’s been there in different models and different turbines. Maybe the way it presented, or its impact, wasn’t to the same extent as what we’re seeing now. That’s where I’d say there’s more to it than just the current. I think I said last time it’s not just a smoking gun. The bearing is sitting in front of a firing squad. You put it all together and now we’re in a tough position. But to Cory’s point, we get brought the application, we get brought the environment, and we get told, “Here, make it work.”

Allen Hall: And you don’t actually see everything that’s happened. You get all the mechanical loads, but they don’t tell you, “Hey, we’re running a hundred amps through this nacelle.”

Loren Walton: No, I don’t remember hearing that.

Cory Mittleider: No, that’s not usually disclosed.

Allen Hall: No one’s ever said that. So that’s a real troubling thing happening in the industry — we’re assigning blame to mechanical components when really it’s an electrical mistake. When you dig into it, what you find is that currents have been running up top for years, but what’s changed now is that with more focus on emissions from inverters, they’ve pushed things into higher frequencies. Higher frequency bands are harder to ground out and get rid of. When things were in the kilohertz range, we could partly ground them and they’d go away. Now we’re working at ten kilohertz and up, and that energy distributes into a lot of places, including the bearings, where it wasn’t before. That’s really hard to deal with. Some electrical designer sitting in a remote location, probably in Germany, designs the circuit, and now you bearing gurus have to go fix it.

Cory Mittleider: And that system’s probably well optimized for that particular package.

Allen Hall: For that particular package, right. It meets all the requirements and does everything they wanted — except for the effect on the bearings.

Loren Walton: You solve one problem and move it to another. That’s ultimately how it works.

Allen Hall: If you’re an electrical engineer, you’d never have thought you were destroying the bearings. The industry has moved quite quickly, though. Everybody started noticing this problem with DLC. They went out to check and figure out what the problem was, and, more importantly, to find a solution. Those solutions are unique, because the reason DLC went on in the first place was to extend lifetime. So if you’re taking the DLC out of the equation, can you still get to those lifetime numbers without it?

Loren Walton: Yeah, and that’s where our message has been that adjusting the material will get you the difference you’re looking for. I want to be very clear: I’m not saying DLC as a solution is bad. When it was applied in the right space — turbines with a lighter duty — it worked great. But once you add in additional factors, it becomes an accelerant to failure at certain points. So it definitely still has its place. But once you move away from DLC, you’re going to be right back where you started — regardless of construction — with the life that was always aided by DLC. Once you’ve removed it, you have to know for sure you’re not going right back to the peeling layers and the spalling you were seeing. From what we’ve investigated, the material changes are where you get that. Having a harder surface combats it, and having a better way to combat any additional debris introduced into the system helps.

Allen Hall: And reducing the possibility of generating that debris.

Loren Walton: Correct.

Allen Hall: So what does that mean in terms of bearing design — different alloys, different heat treats, different coatings?

Loren Walton: The first two, not the third. From the recipe of the steel, adjusting some of the alloying elements, there’s a lot you can do. A lot of people think of engineering mostly through the mechanics of it, but one part of mechanical engineering that doesn’t get talked about is material science. That’s the part we dive into extremely deeply, and it gives you the biggest bang for your buck when you’re moving away from a coating as your — I don’t want to call it a crutch, but as the thing helping you get by — toward changing the bearing from the inside so it lasts better once the coating is gone.

Cory Mittleider: I like describing it as being baked into the cake. It’s not a nice thing added afterward like a coating that’s one to two microns thick. It is the bearing.

Allen Hall: It’s hard to think about steel and a lot of the metals used in the bearing industry as unique chemistries, but they are. There are a lot of varieties of steel, just like there are a lot of varieties of copper or aluminum.

Loren Walton: Yes.

Allen Hall: You’d think steel is just steel — we make cars out of it, airplanes, whatever.

Loren Walton: I was talking to someone who’s more into gears, and even when I spoke of a carbon-nitride version of a bearing versus a carbon-nitride version of a gear, it’s not exactly the same. For all intents and purposes it’s easier for everyone to consider it as steel — one word, means the same thing. But once you get into how much chromium is in it, how much molybdenum, how much manganese —

Allen Hall: It comes down to that, and it can be very small percentages of the total.

Loren Walton: It can make a huge difference. And then you get into the heat treat — your time, your soaking, what you do for quenching. It all matters, and everyone does it differently, so you get different results.

Allen Hall: That’s the kicker. You see a lot of discussions where it’s just, “Oh, it’s been heat treated.” As an electrical engineer I used to see it that way too. But there’s heat treatment and there’s heat treatment. It depends on what you’re doing and what the result needs to be, because you’re changing the whole crystalline structure of the steel. The way you do it and the way you quench it all matters. It’s not one size fits all.

Loren Walton: That’s the part that gets glossed over so quickly, because everyone’s eyes go to what they can see. You change an angle here or there, or the bearing type, and you can see that. It’s different when you don’t have X-ray vision to tell you where all the alloying elements are and in what percentages, and then whether you carburized it, through-hardened it, or carbonitrided it. There’s so much to it that I can see people’s heads start to spin. That’s where we say there are a lot of experts out here — you two are among them, and there are others. Engage in conversations. Ask questions.

Allen Hall: That’s a great call to action — “Cory, help me understand what’s going on.” There’s a variety of bearings out there. Loren’s with NSK, a great bearing company with tremendous history. Those are a couple you can trust. But operators can feel inundated by the guy down the street trying to sell them a bearing, and you don’t know if that’s the right solution for your two-million-dollar wind turbine.

Cory Mittleider: These are critical infrastructure assets. Let’s make sure we understand what we’re doing and why. To Loren’s point, you can open three boxes and they all look the same, but what’s inside is what really matters.

Allen Hall: It’s a tremendously difficult business. With as many main bearings getting swapped out today, over the last couple of years there have been a lot of decisions made on the fly — some correct, some really wrong.

Loren Walton: I’d hesitate to say wrong, because I think people are doing the best they can. It’s not because they’re not trying.

Allen Hall: It’s because they don’t have the knowledge in front of them, or maybe they haven’t made the call to Malloy or NSK yet to get the ground truth.

Loren Walton: What you mentioned a second ago is pivotal. There’s been enough selling that we’ve kind of gotten away from the engineering. People hear “sales engineer” and they cut off at “sales.” If we can get back to the engineering, a lot more people will improve their assets. And it doesn’t have to be just listening to Cory and me — poll the audience. There are a lot of us out here. Everybody has a different background; we all know a little about this or a lot about that. Take the opportunity to learn. I’d liken it to your personal life: you wouldn’t buy a new vehicle or a stereo system without doing your own research. You wouldn’t just listen to the salesperson and buy the first thing you see. It’s the same here. If you’re making decisions without engaging at least the top three to five people in this space, you’re doing yourself a disservice.

Allen Hall: And that’s what happens a lot, because people get pushed. There’s a timeline, especially now with the repower situation — “I’ve got to put something on now.”

Cory Mittleider: Right. And new platforms — the next-generation three, four, five, six megawatt platforms, and offshore — are having their first failures. We need to learn from it. That’s where we’ve worked with operators to participate in the teardown and collect the sample. We get clues, we mark it up, and we do a lot of the investigation — metallurgy, metrology, raceway traces — to inform us on what the problem is on that specific platform.

Allen Hall: As we get to these bigger turbines, some data is coming back on O&M costs relative to a one or two megawatt machine, and it doesn’t scale linearly. It goes almost exponentially, because everything is more expensive. Replacing a bearing on a six megawatt machine is a much more expensive ordeal than on a two megawatt machine. What should we be paying attention to and monitoring more closely on these larger machines? The new shiny turbine is great, but that doesn’t mean you don’t have to monitor and maintain it.

Loren Walton: I’d start with verifying all your original fits and clearances. We’ve had cases with a four-point mount main shaft — two main bearings — where one side wasn’t installed properly from the beginning, so it didn’t actually float. It’s supposed to be a fixed side and a floating side; now you’ve got one side that’s not floating, and you get overload. So make sure you’re set from the start. A lot of machines now come already outfitted with instrumentation — vibration monitoring, oil monitoring, different ways to start trending from the beginning. Back when we got started, that wasn’t the case. You got your new turbine and in a lot of cases it had nothing on it — you were flying blind. Now that it’s there, use it.

Cory Mittleider: That’s a good point. Specifically to bearings, something earlier versions didn’t have, and newer ones mostly do, is auto-lubers.

Allen Hall: I see more of those lately.

Cory Mittleider: That’s great from a lubrication-delivery and reliability point of view, but it’s its own little machine. We’ve heard of cases where the auto-luber failed, or ran when it shouldn’t have, or for whatever reason had very large output. So you need regular assessment of the entire system, including uptower.

Allen Hall: You’ve got to monitor everything that’s uptower.

Cory Mittleider: It’s its own little machine. It requires its own maintenance. If you’re relying on it, you’ve got to check it.

Allen Hall: As we move into these larger machines and see more of them deployed, what are the useful things you should be doing in that first year to make sure your bearing is working optimally? Is it just checking vibration levels? Is it getting uptower and doing a quick sweep to confirm the grease isn’t oozing out where it shouldn’t be? Is it that simple?

Loren Walton: Having a regular maintenance interval definitely helps. Even getting grease sampling to understand your baseline levels after the first six months and the first year. In a lot of cases the turbines are under a couple-year warranty, so maybe you don’t have as much access. But as much as you can, getting a baseline is huge, because you’re going to want to compare later. You’ll want to say, “Okay, I took this grease sample — what does it mean? Does it normally run that high or not?” Same for vibration, getting the trending. For main bearings in general, more grease is better than less, because you can never quite get it all out when you’re regreasing. So a lot of that first year or two is about getting a good baseline so you know what you’re actually expecting, and what it means when you take a reading in year two or three.

Allen Hall: What does a grease sample look like in terms of the response you get back? I take a sample, send it to a lab, and it comes back with — what? Is it “good or bad,” or a bunch of chemical numbers about composition and dirt? I’ve never seen one.

Cory Mittleider: It’s a matrix. You can request different versions, but probably ten or fifteen different elements they give you numbers on, in parts per million. Iron and brass will be up there.

Allen Hall: So if you see something floating in the grease —

Cory Mittleider: Silicon, phosphorus, water.

Allen Hall: Water would not be great.

Cory Mittleider: No.

Allen Hall: So those reports come back, and I assume there’s more knowledge needed to interpret the results. What do you do?

Loren Walton: We have some guidelines we share with our partners and customers. If you see a certain amount of parts per million of copper, ferrous material, or the like, we can say, “That’s worth monitoring for a while,” or “You should probably purge it, try to get it out, and see if it stabilizes.” We get those questions and respond in kind. There’s definitely help available. If we work together, we typically have a lot more success. A lot of people right now feel like they’re trying to work in their own silos, and you don’t have to do that. You don’t have to be the subject-matter expert for lubricants, gears, bearings, and everything else. You can reach out to experts who can help, and hopefully that frees up your time to assess and work on other things.

Allen Hall: The turbines are so complex today. It used to be you could have one person on site who knew most of what was going wrong, because they’d made thousands of these things — there was a legacy. When you get to six megawatt machines, where you don’t have a lot of history, particularly in the United States, there’s really no one to ask. You’d better find somebody who knows what they’re talking about.

Cory Mittleider: And the operators are responsible for multiple systems — six or seven or eight systems they’re looking at. We can help with bearings; we’re niche and focused on that. If we can take that off your plate, now instead of six systems you’ve got five to worry about.

Allen Hall: That’s key. There are experts out there, and one thing the podcast is trying to do is give those experts a chance to talk so you know who to ask. Your phones should be ringing right about now, because it’s repower time, and it’s main-bearing repair and replace time, pitch-bearing repair and replace time. There’s a lot of bearing activity going on. I always say call Malloy Wind if you need somebody who really knows their stuff, the technology, and what’s going on internally. How do people get ahold of you two if they have questions? What’s the easiest way?

Loren Walton: I try to be at most of the industry events. We usually hold a booth. And my email, my phone number — I’m on LinkedIn, so reach out there. After our last discussion I had a few folks reach out, actually mostly from other countries. It was interesting; we heard about a few issues before they even hit the US. Some folks were having problems with the larger turbines, and we were able to get our teams in Brazil and Spain involved right away. Then once it started cropping up in the US, I could say, “Yeah, I already solved that.” We can put my email in the show notes.

Allen Hall: We’ll put it in the show notes for sure. And Cory, how do people get ahold of you?

Cory Mittleider: I’m pretty active at the events — ACP, and the Drivetrain Reliability Collaborative is another one we had a couple of months ago. Email, phone, and I’m pretty active on LinkedIn. I’ve had similar experiences to Loren, getting contacted from other countries across the globe. It’s fun to investigate problems and share results in the technical articles on our website, and have people send me a picture of an article I wrote and say, “Hey, let’s talk about this.”

Allen Hall: Your articles are great. Check out malloywind.com — just Google it and it’ll come right to the top. If you have bearing questions or something you’ve seen, that website is a great first place to get some answers. It’s very helpful. Well, Loren and Cory, I love having you on the podcast. We need to have you on more, because there’s a lot going on in the bearing world.

Loren Walton: There are things we didn’t even touch on today.

Allen Hall: You’re always welcome back.

Loren Walton: Awesome. Appreciate it.

Allen Hall: Thank you.

Malloy Wind and NSK on Main Bearing Failures

Renewable Energy

MAGA Republican Runs in Wyoming

Published

5 hours ago

August 7, 2026

Alice Rush

Meet Reid Rasner (photo at left). He’s a MAGA Republican running for congress in Wyoming–that’s a good fit.

He faces three challenges, however:

1) He’s openly gay, a terrible fit for Wyoming,

2) His politics appeals only to the true idiot. While it’s true that voters there are not well-educated, they’re aware and alert. They’ve seen trickle-down economics fail consistently since the days of Roland Reagan, and they’ll be very hard to convince that democratic socialism as it’s implemented around the world makes the nation’s citizens poor, and

3) I hate to judge a book by its cover, but he looks like a dullard.

MAGA Republican Runs in Wyoming

Renewable Energy

Congress Should Address the Climate Crisis

Published

11 hours ago

August 7, 2026

Alice Rush

Asking the congress to “address the climate crisis” is something of a joke. Most of them have their seats by virtue to their allegiance to Big Oil, and, for many, their position on climate change is that it’s a hoax.

Congress Should Address the Climate Crisis

Renewable Energy

IWTG Consulting on Pitch Bearing Cracks, Loose Root Inserts

Published

2 days ago

August 6, 2026

Alice Rush

Weather Guard Lightning Tech

IWTG Consulting on Pitch Bearing Cracks, Loose Root Inserts

Jon Zalar, founder of IWTG Consulting, joins to discuss broken blade bolts, cracked pitch bearings, loose root inserts, and early detection.

Welcome to Uptime Spotlight, shining light on wind energy’s brightest innovators. This is the progress powering tomorrow

Allen Hall: Jon, welcome back to the program.

Jon Zalar: Thanks for having me.

Allen Hall: Uh, last time I saw you, we were in Melbourne- Yep … at WOMA 2026, and that was a huge event. We know we’re gonna do it again next year in March three, the 3rd through the 5th, so you’re invited back, of course- I can’t wait … if you can make it. Yeah. Yeah.

It’s gonna be, it’s gonna be a good time. A lot is happening in the blade world and in the wind turbine world more broadly. A lot of things we’re hearing right now are related to blade bolt connection, pitch bearing inserts still. A lot of that still happening in the United States. What is the current status of, uh, the blade connection issues in the US?

Jon Zalar: I feel like it’s a growing [00:01:00] issue, not super, super fast, but it seems to be getting a little worse. There’s, you know, more bolts breaking at that joint. Um, pitch bearing cracks are, seem to be pretty common. There’s different solutions for it, and then, you know, the root inserts are another thing that we’ve talked about before that seem to be happening more and more, or maybe more and more people are finding them ’cause they’re looking.

Allen Hall: What are the first indications that you have a blade bolt or some sort of joint issue at the root of a blade? What can you see?

Jon Zalar: A bolt laying in the hub bouncing around. Um, you know, from like a– looking at it from, like, the sensors on the turbine, it’s really hard to tell unless it gets really bad. Uh, some of the OEMs have some analytics developed to kinda start to indicate if there is a aero change because there’s missing bolts or root inserts are coming out, and they’re using that as a way to go figure out which ones to go inspect first.

Allen Hall: Really? Yeah. You think [00:02:00] the SCADA data will give you some indication that you have a, basically a little bit of a loose blade?

Jon Zalar: Yeah. I, I, I think because the number of turbines and the number of data points you have, I think there is a pretty good analytic out there right now.

Allen Hall: Wow. All right. I think a lot of our operators have not taken advantage of that.

Is, is that just b- based on the high-speed data, SCADA data, or is it low-speed data you could see that same effect?

Jon Zalar: I believe it’s on the low-speed data as well, but I bet the high-speed data was used to kinda develop it.

Allen Hall: Wow. All right. So that’s a huge help to operators. Yeah. So what are you looking for if you’re looking through SCADA data, what would be the couple of markers there that say, “Hey, maybe we ought to go look up at the– in the hub”?

Jon Zalar: I don’t know exactly what they’re using, but they would basically look for maybe an imbalance or looking for certain components that are being overworked.

Allen Hall: Oh, sure. Okay.

Jon Zalar: Yeah.

Allen Hall: So your pitch actuator may be getting a little bit overworked. It would seem like one of the places- I think that, yeah … that would get loaded, right?

Jon Zalar: Mm-hmm.

Allen Hall: Okay. [00:03:00] And any vibration monitoring going on? Because it, it, uh, in some cases you’re– I’m hearing, like, millimeter gaps-

Jon Zalar: Correct. Yeah …

Allen Hall: between the blade and the pitch bearing.

Jon Zalar: So probably a combination of the ALC sensors, at least on a GE turbine, looking at that. But the PCH box also is looking at the tower vibration, so it could be a combination of all three.

I don’t know the exact- Okay … details, but between all of that, I think there are some analytics that kinda say, “Hey, go take a look.” And then I think there’s some other companies that have- tools that go monitor it.

Allen Hall: Mm-hmm.

Jon Zalar: Dial indicators remotely or even, you know, people going up there with dial indicators to go kind of rotate the rotor and kind of see if there is gapping between the blade and the pitch bearing.

Allen Hall: Is that a safe situation in your– from the gapping? I’ve heard this where they’ve basically took shims and they’re trying to measure this gap or some sort of dial indication. Is that a smart thing to do? Is it even reliable to do it that way? [00:04:00]

Jon Zalar: I, I, I think there’s some reliability there. And like, you know, these are really big parts, right?

So like a little bit of gap, it, it’s probably expected to a point, but growing gaps is where you should be a little more scared.

Allen Hall: So you’re– you would have to go do that quarterly, monthly, weekly? How, how often would you have to do it to see the progression? Because I’ve heard stories of, uh, a couple of weeks from nothing to hub crack to, “Oh, it took a year or more.”

Jon Zalar: I think it depends on the issue. I think for– if you’re looking at that, the bolted joint itself between the root inserts and the, uh, bolts breaking itself, I, I think they’re doing about quarterly. Now, the pitch bearings inspections are also quarterly. They’re al- they’re, they’re leveraging the drone inspections for the blades, and they’re looking at the pitch bearings to see if they’re cracked, right?

Uh, you guys are doing that too.

Allen Hall: Okay.

Jon Zalar: I think Coraly is doing a good job mitigating the risk, feels like.

Allen Hall: Wow. All right. [00:05:00] Yolanda, looking at pitch bearings, you’ve looked at a lot of drone images in your lifetime. Mm-hmm. How much can you see on drone images on pitch bearings? Can you see cracks and, or y- or do you see grease, which is a really indication that something is wrong in the bearing?

Yolanda Padron: You can see grease. You can see the cracks pretty, pretty well. Yeah. The drone images are, are really high quality. Uh, but you did mention that it’s something that you’re seeing a lot more. Is it because there’s a lot more aging fleets, or is it a problem with a lot of the new turbines that are coming online?

Jon Zalar: I, I think it’s an, I think it’s a more of a fatigue problem, so the aging of the fleet. And also, I think more people are looking at it, right? ‘Cause, like, initially the drones that were looking for blade cracks weren’t looking at pitch bearings, but then pitch bearings started cracking, so now they added that to whatever they buy off the drone companies, right?

Go look at my pitch bearings, for example.

Allen Hall: Hmm.

Jon Zalar: So I, I think it’s a problem of the more you look sometimes, the more you find.

Yolanda Padron: Hmm.

Jon Zalar: Yeah.

Allen Hall: So we [00:06:00] have root insert issues, which are being addressed by a couple of different companies- Yes … uh, uh, with somewhat similar solutions. OEM is offering one right now also.

Jon Zalar: I, I think there’s three solutions. There’s two uptower that are basically looking at ways to go fill the void between the root insert itself and the blade root. Um, and I– there’s another company that’s also more of a downtower solution where they’re actually, like, r- drilling out the root inserts and putting new ones in that are gonna last better, longer.

Allen Hall: Okay. So the drilling out is, would be CNC onsite. Correct.

Jon Zalar: Yeah.

Allen Hall: And they’re based over in Europe. But th- the drilling out is a take the blade down, set it on the ground sort of- Yeah. Right … doing really fine machining on the, on the blade itself. So that, that’s a different, completely different insert that’s going into that-

Jon Zalar: Correct

Allen Hall: new hole or- Yep … clean hole, right? So it’s a, just a, uh, totally different kind of product versus trying to inject [00:07:00] some s- sort of epoxy or resin into the, the void.

Jon Zalar: Right. Yeah. Uh, I mean, you would prefer to do it uptower. It’s gonna cost you less money.

Allen Hall: Sure.

Jon Zalar: But you wanna make sure you do it right, so I think, uh, I do foresee it being a combination of both solutions kinda going forward.

Allen Hall: Is it dependent upon, like, how much damage has been already done, or what the fatigue w- uh, an estimate on what the fatigue life is?

Jon Zalar: I think it’s strictly on measurement perspective right now. So how much gapping you have, um, kinda determines what potential solutions you have.

Allen Hall: So the gaps aren’t big, right?

So the, the gaps I hear are one millimeter is k- kind of sort of start a problem.

Jon Zalar: Mm-hmm.

Allen Hall: Three millimeters is, “I need to be making decisions.”

Jon Zalar: Yeah. So- That, that’s what I’ve heard, too. Yes.

Allen Hall: Three millimeters is about a eighth of an inch.

Jon Zalar: Mm-hmm.

Allen Hall: So it’s not a lot of m-

Jon Zalar: But you can see sunlight through it if you’re s- down there.

Allen Hall: Okay. That’s not… Well, you should see. That’s not

Jon Zalar: good either. Yeah.

Allen Hall: Right. Okay. So in a, in a three millimeter situation then, you’re doing what? [00:08:00]

Jon Zalar: You’re trying to decide if the uptower solutions are something you wanna go try, ’cause they’re still in the trial mode from my understanding or-

Allen Hall: Okay …

Jon Zalar: people are learning a lot.

So I think when you get to that point, you’re calling some of those companies to say, “Hey, I have this issue. I got a couple blades with, you know, .3. Can you guy- you guys wanna come take a look at it, see if your solutions, if you guys wanna go use it or not?” And then I think the ones that get too bad, from my understanding right now, is they’re, they’re replacing the blades.

Allen Hall: So they’re taking the whole blade down.

Jon Zalar: Yes.

Allen Hall: And what’s the thought process in that? Uh, versus drilling out the inserts and putting new inserts in. Is there just a composite degradation that’s happened around those joints that it just puts it at risk or, or you have actually aged the blade much faster than you would otherwise have done?

Jon Zalar: I, I think they aged that particular connection too much. So I, I- Wow … either between the [00:09:00] fatigue or lack of epoxy resin, w- whatever the actual root cause is for that root insert coming out, when it gets that bad, it’s like you’re not gonna be able to inject enough To make it adhere

Allen Hall: You can’t de-age it.

Jon Zalar: Correct.

Allen Hall: Right?

Jon Zalar: Yeah.

Allen Hall: Bring back the youthfulness of the blade. Wow. All right. And we have seen this worldwide. I know in the, in the States you hear about it all the time, but it, this seems to be not a US- Correct … problem.

Jon Zalar: It’s a worldwide problem, yes.

Allen Hall: Okay. So if, if it’s a worldwide problem, are there more solutions on the way?

I know you talked about three of them already.

Jon Zalar: I have not heard of any other ones except those three as of today.

Allen Hall: Wow.

Jon Zalar: There could be other people working on it. I think there should be.

Allen Hall: So, yeah. You would think so, yeah. So we’ll, I guess we’ll eventually hear about it on the podcast. Usually people with technology will contact us.

They might call,

Jon Zalar: yeah. They might call you, they might call you tomorrow.

Allen Hall: Sure, they may. So that leads to sort of a subsequent issue, which I think is getting grouped together. So the [00:10:00] hub crack, pitch bearing crack, root insert pullout issue is also discussed with blade bolts being broken.

Jon Zalar: Correct.

Allen Hall: Are they related or are they separate engineering problems?

Jon Zalar: If you look at them individually, you’d probably come up with some separate answers, but if you combine them all together, you kind of start looking at is there too much loading happening in the leading and trailing edge of the blade? ‘Cause the hub cracks, the root inserts, and the blade bolts, from my understanding, are happening at those two highly loaded areas of the, the blade or that whole rotor connection.

So I mean, I do feel the root cause is probably a little higher loads than anticipated.

Allen Hall: I think everybody’s talked about when they’ve done the injection method and the drilling method, all they’re discussing is leading edge, trailing edge.

Jon Zalar: Yes.

Allen Hall: And how– It’s a question of how many- Correct … are you gonna replace.

So th- [00:11:00] that’s, those are the two highly loaded spots on the bolted connection.

Jon Zalar: Correct.

Allen Hall: And that’s where blade bolts are also breaking or, or the bolts breaking elsewhere around the periphery?

Jon Zalar: I don’t have all the data, but what I had seen, it’s very similar areas.

Allen Hall: So if you don’t pull the insert out, you’re then loading the bolt.

Cr- Right It’s one or the other, right? Right. Yeah. So the, the, the load path is the load path, so it’s coming through the insert into the bolt. Bolt’s carrying it into the pitch bearing. Pitch bearing’s carrying it into the hub.

Jon Zalar: Correct.

Allen Hall: Hub carrying it downtower. So eventually, one of those, uh, links in the chain is- The weakest.

Yeah … is, is the le- is the weakest. What is it about blade bolts that is so dangerous? We hear– we walk onsite to an O&M building, there are signs saying, you know, “Pay attention for loose bolts. Look around on the ground for loose bolts.” We’re gonna– and as electrical engineer, like, “Whoa.” Bolts should not be falling out of this tower.

What i- what is that sort of sequence where a [00:12:00] bolt would escape from the nacelle?

Jon Zalar: So let’s just use one bolt. One bolt breaks, falls in the hub, bouncing around, doing some– potentially doing some damage inside the hub. And ’cause these turbines, you don’t need to go out there every day ’cause they do run pretty good, right?

Right. You just do your regular maintenance. And if you don’t really know about that, ’cause, like, it bounces around for a while, then it usually gets, like, lodged behind a, uh, either center box or pitch cabinet or actually in the front sometimes. Kinda don’t know it happened. But, you know, frees itself up, keeps bouncing around, it, it could escape through the hatch covers ’cause, you know, people have to get into the hub anyway.

And I’m sure a lot of people listening here that have sites, like, you know, probably found some bolts laying on the ground, which is a little scary.

Allen Hall: Right. So is, is the busting the hatch opening levers? I know there, there’s a couple different ways to get into that hatch. Yeah. But, uh, is it just completely busting the hatch?

Yeah. So it’s– [00:13:00] okay. So you see a– so if you see a loose hatch panel, you have an issue. You probably gotta be careful about coming up on that turbine?

Jon Zalar: Potentially. A lot, a lot of hatches are, you know, not always maintained well.

Allen Hall: Right. I’ve seen them, I’ve seen loose ones, yeah.

Jon Zalar: Yeah.

Allen Hall: Okay. So that, that would be a sign that– but though if, if you’re approaching a turbine, one look on the ground.

And Yolando, you, you’ve seen a lot of turbines. So are you, are we looking on the ground and seeing what’s around the turbine before we approach the turbine now? Yeah. Just, just a sanity check?

Yolanda Padron: Yeah. Be aware also of what’s happening on site, right? Because if it’s some- if it’s a problem on site, you need to be extra careful when you’re approaching any turbine there.

Uh, is it something that people maybe should start thinking about implementing, like, a sensors earlier on than when they’re seeing the issue actually happen?

Jon Zalar: Yeah. I, I, I think that’s a potential, ’cause it, the quicker you catch it, the less damage you’re gonna do, and it also reduce the risk of [00:14:00] it, um, falling out of the hub And I’ve worked with a couple of my, uh, customers for some, like, potential ways to detect it.

Still kind of trialing it right now. But I, I do think there’s gonna be some benefit from a safety reduction, but also from a strictly a damage. ‘Cause, like, you get a couple bolts bouncing around there, and you bang up some cabinets or some pitch motors, that’s expensive and hard to go fix.

Yolanda Padron: Yeah, we were talking about it earlier too.

Like, it goes down, it can hit a transformer, it can hit, like, a truck or someone.

Jon Zalar: Chance of it hitting someone. Yeah. I mean, I don’t care what hard hat you have on, it’s not gonna do anything.

Yolanda Padron: Yeah.

Allen Hall: So what kind of sensor should you be putting onto the turbine if you don’t have access to the SCADA data or you don’t know what the correct algorithm is to suss out there’s something wrong up there?

But a, a bolt breaking is not gonna be something that a SCADA would even pick up, I don’t think. One bolt out of the whole- Yeah. No.

Jon Zalar: No way. Okay. I mean, there’s a– I think there’s, like, [00:15:00]one company looking at more of a, like, mechanical way to, like, prevent the bolt from coming out. I forgot the name of it.

Allen Hall: Okay.

Jon Zalar: Um, and then what I was looking at was more of a, like, you know, microphone type detection to kind of listen for that.

Allen Hall: It would make a lot of noise.

Jon Zalar: Yeah. It seems like it works. It, um, yeah, still more development needed on my end.

Allen Hall: So- The engineer in me was, is saying, “Why are we not putting strain gauges on bolts?”

I picked on the leading and the trailing. It’s like right dead center there to look at, even if it’s just two strain gauge bolts to see what the loads are.

Jon Zalar: So like there are s- there are bolts that are, or that are made with the strain gauges built in that you can use to go, you know, monitor that. But you also need to understand like what was the design intent.

So unless you’re working with the OEM, you don’t really know what you’re seeing is good or bad. You just say, “Oh-

Allen Hall: You just see a number.

Jon Zalar: Yeah. Right. I mean like, and if you install, I don’t know, four, you’d be like, “All right. Leading and trailing edge are higher [00:16:00] than the other two.” Well, yeah, it’s supposed to be, but like is a 10% difference expected or not expected?

Allen Hall: Is that something where if you’re, especially if you’re in a full service agreement, and a lot of these turbines are- Yeah … for the first couple of years, if you were to do that, it’s something you would just say to the OEM, “Hey, this is, these are the loads we’re seeing from the strain gauges on these bolts.

Does this make sense to you?” Or, or would an OEM just not even respond to that kind of inquiry?

Jon Zalar: I mean, I think it’s all about relationship with the OEM. I, I, I think

Allen Hall: it- I think they would wanna know.

Jon Zalar: I have a feeling they probably are looking.

Allen Hall: Okay.

Jon Zalar: I mean, ’cause I mean they have the test turbines too that they probab- that, that I know they have instrumented heavily.

Allen Hall: Yeah. So they, they’re probably getting at least some feedback. Th- that’s the problem. Yeah. And you worked on the other side, right? I have. So you worked for an OEM doing the RTAs. The first problem is you don’t have data, so now you gotta go get the data.

Jon Zalar: Correct.

Allen Hall: And that data is not available tomorrow. No.

‘Cause you’re gonna have to go run some sort of design of experiment to go figure out if [00:17:00] there is even a true problem or even what the root causes could be.

Jon Zalar: And it, and it’s expensive to go instrument a blade and get the data back at the right speed and connected to the turbine data. I mean, I rem- I, I used to say it’s about like 300 to 500,000 to go put a couple gauges on a blade just with all the equipment you need to get the data correct.

Allen Hall: To get the right data.

Jon Zalar: Get the right data at the right frequency connected to the controller. It’s, it’s very expensive.

Allen Hall: Wow. Okay. Yeah. I, I don’t, I don’t see a lot of operators doing that.

Jon Zalar: And especially connecting it to the operating data, right? So like if you go put a strain gauge and I don’t know, you’re curtailed, you’re only making, I don’t know, a megawatt- Doesn’t matter.

And if you don’t know what the turbine’s doing and you’re looking at this, like, strain gauge data, it’s really hard to correlate anything.

Allen Hall: So you need a full suite of data. Yeah. That includes weather data- Yeah … at some level, right? Gust winds and- Oh,

Jon Zalar: yeah …

Allen Hall: average wind speed. You need the anemometer. You need which, which way [00:18:00] the n- cell’s pointing.

Y- uh, you would need a lot of information- And what the controller’s- … to even suss it out …

Jon Zalar: and what the controller’s doing, right? Right. ‘Cause, like, every turbine, the controller’s trying to, like, you know, balance the rotor the whole time. It’s trying to, you know, micro pitch depending on what the winds are doing.

And if you don’t know what all that stuff’s doing, like, it’s really hard to correlate a strain gauge measurement to is that bad or not.

Allen Hall: It’s a complicated problem.

Jon Zalar: Yes. That’s why RCAs take, you know, a long time, and they’re not done in two weeks.

Allen Hall: No, they’re done in a year.

Jon Zalar: Yeah.

Allen Hall: Typically, or longer. So what should an operator be thinking about now?

If, if we s- get our drone images back, we’re scanning through them like, “Oh, there’s a crack” What am I doing next besides calling you and connecting to your LinkedIn page?

Jon Zalar: So right now with the pitch bearing crack, um, some of the OEMs are providing stiffener plates to put over the crack and try to run it.

Allen Hall: So that’s a doubler plate, basically. A double plate. Doubler

Jon Zalar: plate, yes. [00:19:00]

Allen Hall: Yeah. Okay. So even in a, in a crack scenario, that pitch bearing, if given mechanical support, can run like that?

Jon Zalar: That’s my understanding, yes. That, that potentially could run for some period of time. I don’t know if it’ll make it 20 years or not, but it’ll buy you time for sure.

Allen Hall: Does that involve a crane to do that work or is that just… My recollection, that was in pieces, like there, it’s not a ring, it’s a, a couple of pieces that you’d be able to bolt on without taking the-

Jon Zalar: No, it’s a- … blade down … it’s a, it’s a single piece that-

Allen Hall: It’s like a single casting kind of thing.

Jon Zalar: Right. And I, I think you need some like small crane, like a jig crane or one of those-

Allen Hall: Just to support the blade while you do it?

Jon Zalar: And to go put it in, right. Okay. Yeah, I don’t think, you’re not taking the blade off. You’re not taking the

Allen Hall: blade down.

Jon Zalar: Correct. Yeah. It’s, it’s done with the blade up there.

Allen Hall: Okay.

Jon Zalar: You’re putting new, putting longer studs in and putting the plate on.

Allen Hall: So first step is let’s get the joint reinforced. Right.

That’s the easy first step.

Jon Zalar: Right. Although there has been some cases where since [00:20:00]you’ve put that stiffener plate on, the loads get spread out to the end of the plate, and then you- Sure … you could see cracks there.

Allen Hall: Okay. All right. So the loads- It, that- … have to go somewhere …

Jon Zalar: loads have to go somewhere. That’s, that is a bottom line.

Allen Hall: All right. So you’re just changing where the load path is, so you have to be cognizant of that. Okay. Sure. Fine. But if you have, uh, especially in the United States, you don’t have 10 of these turbines, you have 50, 100- 100 … 200, 300 of these things, or thousands as it, as it turns out. Are there simple solutions that can be applied to, just to give me a sense, like that turbine’s having a problem, but the one next to it’s not, and, and just, just from a maintenance spin standpoint where I’m not just blanketing everything and trying to do everything to all these turbines at once, how do I, how do I manage this?

Jon Zalar: I, I think it’s like being very observant. So like, you know, making sure you’re looking at the pitch bearings from the drone images, right? Um, also talking [00:21:00] to your maintenance people like, “Hey, are, are you finding a bunch of broken bolts? Like, what positions?” Like, you know, if I was back at the OEM, I would like to have as much data as possible on this issue.

Like how many bolts are, when did you find them, what positions? A lot of times we, when I was there, like we would not get all that information, so it’s like really hard to run an RCA without that information.

Allen Hall: Sure. Yeah, where did this bolt break in the ring?

Jon Zalar: Right.

Allen Hall: Could tell you a lot. Is it just a b- bad lot of bolts, or is it something more load related?

Jon Zalar: Correct.

Allen Hall: Wow. Okay.

Yolanda Padron: Yeah, I think that’s a really good point, too, to make sure that you’re connected with like every stage of the operations. ‘Cause I know that everybody’s obviously really, really busy on a wind farm, but it’s really common for like an engineer to have certain data and the site team to just be running around and having a lot of data, but maybe they don’t realize that, oh, it’s important to know how many bolts per tower are coming down.

Jon Zalar: Correct. Yeah

Allen Hall: That’s a lot of work

Jon Zalar: It definitely-

Allen Hall: It’s a tremendous effort if you’re gonna [00:22:00] go after this problem and, and solve it RCS

Jon Zalar: are hard. They

Allen Hall: are. Yeah. All of it. Yeah. Machines are complicated today. There’s a lot of computer-driven s- things about them, and then you have these loading issues, and you have composite materials.

Th- there’s just, y-

Jon Zalar: you got to get- It’s a very complex

Allen Hall: It’s a machine, right? Yeah. It’s a complex machine. So how do people reach out to… You’re, you’re the head of IWTG, which is based in South Carolina, but you do consulting worldwide. Yes. And, and you are a huge resource because you understand the complexities of these problems.

How do people get ahold of you and, and get something started if they have a, a, a blade bolt issue or an insert issue or a cracked pitch bearing? Where do they start?

Jon Zalar: They can send me an email, jzalar@iwtgconsulting.com.

Allen Hall: Okay. And you have a great LinkedIn page, so you can connect with you on LinkedIn.

Jon Zalar: Yes.

Yeah, I have one

Allen Hall: of those. Yes. Or you could just come to WOMA in [00:23:00]2027. Yeah. You can. You can meet John there and, and arrange everything there. So John, it’s great to see you, and thank you for coming up. We, uh, we’re recording this at the world headquarters of Weather Guard Lightning Tech, and, uh, John just lives down the street in, in, in US terms.

Yeah. So it’s, it’s great to have John come and visit us up here in North Carolina. So John, thank you so much for joining us.

Jon Zalar: Thanks for having me. Appreciate it.