Solving Wind Turbine Pitch Bearing Problems with Malloy Wind

We interview with Cory Mittleider of Malloy Wind, a company
specializing in providing bearing solutions for wind turbine
applications. Cory shares insights into common pitch bearing
failure modes, how Malloy Wind analyzes failed bearings to develop
improved designs, and the importance of factors like grease and
manufacturing processes in bearing longevity. Visit
https://www.malloywind.com/ for more info! Sign up now for Uptime
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This episode is sponsored by Weather Guard Lightning Tech.
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www.weatherguardwind.comIntelstor - https://www.intelstor.com Allen
Hall: Welcome to the special edition of the Uptime Wind Energy
Podcast. I'm your host, Allen Hall, and I'm here with my co host,
Joel Saxum. If you were an owner, operator, or technician in wind,
you have come across pitch bearing problems. And those pitch
bearing problems can get really hard to detect early. But once you
see them, they're expensive to repair. So Joel and I thought it was
time to bring on an expert. In bearings to the podcast. So our
guest today is Cory Mittleider of Malloy Wind. And Cory has an
extensive background in wind bearings. Now, Malloy, if you're not
familiar, is based in Sioux Falls, South Dakota, which is in the
middle of the United States. And Malloy Wind specializes in
providing solutions for wind turbine. applications. So they're a
total wind focus organization. They offer a variety of services,
including upgrading gearbox bearings, blade bearings, main shaft
bearings, pitch motor renewals, and generator bearings. Cory,
welcome to the program. Cory Mittleider: Hey guys, thanks for
having me. Allen Hall: So there's so many questions about pitch
bearings and just having been down in San Diego at the ACP OMNS one
of the complaints is, Oh, I got a huge bearing replacement program
going on this summer. And my first thought was of you were
thinking, wow, you guys must be really busy because Bearings are
probably after lightning, it's lightning and then bearings were one
and two of the problems for wind turbines at the moment. Cory
Mittleider: Yeah, it's been it's been a busy couple of years.
There's certainly standout platforms that are having their own
platform specific failure modes that we're discovering as we work
with operators. Joel Saxum: Yeah we talked a little bit off air
about some of that thing. Okay, so we're in lightning space. We
know if someone calls and says, I have this turbine with these
blades, you go, Ooh, you got problems. So I know that it's the same
thing in the Bering world, generators, like you know the ones that
are going to happen. So when you guys initially talk with someone,
What are some of the points that you asked them right away? Okay.
They've called, what are we looking at? Cory Mittleider: Sure.
Sure. So to your point, it's a lot of platform specific. We know
platform X has this history of problems. Platform Y has a different
set of history and platform Z is a pretty stable, pretty robust
platform, for example. So we start to, to investigate, is it one of
those platforms that we already know has some issues that we either
maybe have something developed for, or are currently working on. We
talk about how soon are they experiencing their first failures or
how are they detecting them? And most importantly, I think is how
long do they plan to run the site? Are they two thirds of the way
through the life of the site? Then, we probably propose a different
solution to them than we do to some of the worst case scenarios
where they're having failures in the three year ballpark and
they're trying to get to 25. Joel Saxum: Yeah, no. One of the
things that we talked about was, hey, you're on platform A. With
bearings, but you have bearings B and C, same design. But different
manufacturers, and sometimes you run into issues there as well.
Cory Mittleider: Yeah. It's really interesting when it comes down
to it. There's only four parts in a blade bearing. There's the
rings, the rollers, the seals, and the cage or the spacers,
depending on the configuration. It sounds easy, right? But there
are a lot of process controls quality checks, things like that.
That can be done to ensure. The best long life operation. We
actually got a call about three years ago from an operator in our
neighborhood that said we have platform a and we have two bearing
manufacturers installed across our fleet, all from original build.
The site was about 10 years old. They said, why are all of brand X
failing and none of Brand Y. So we worked with them. We
investigated that a little bit and we found exactly that, that the
bearings are the same dimensions, from a raceway load capacity
point of view they should have been the same, but what we found is
it was some subtle manufacturing differences from the way the the
races were hardened. control point of view. And corrosion
protection of the bolt holes, for example, that were leading to
that. So very small details, right? That lead to larger
implications a decade later. Allen Hall: And just seeing some of
the pictures. That Malloy Wind has on its website and there's some
great technical information about bearings. So if you want to know
anything about bearings, go to the Malloy Wind's website and start
looking at the technical explanation, because it's written in
English for in simple terms that even I can understand for me.
Yeah. For people like me that don't know a lot about bearings, that
was really helpful because I'm a picture person, right? I want to
see how, what the, how these things break down. The pictures of
these pitch bearings coming apart was fascinating because
essentially, from what I could tell, it starts to degrade
internally and it starts to blow out the seal. So it starts
spitting out metal parts that. Once that begins, it's bad stuff.
You really can't fix it from there. That's my understanding of it.
Cory Mittleider: Yeah, then maybe I'll dive into that, right? Yeah,
to your point and you mentioned right at the top that blade
bearings are almost impossible to get a health assessment on. It's
not like a high speed gearbox bearing where you've got vibration
and temperature because it's running fast and at full revolutions.
But Blade bearings are they don't ever go full revolution and they
go so incredibly slow. So you really can't apply any of the
traditional bearing monitoring tools. That we're used to, right? So
health assessment is incredibly difficult. Even when you look at
the construction of the traditional two row four point bearing type
that's used as a blade bearing it actually stops you for the most
part, for most part from even trying to bore scope them. Joel
Saxum: But you can't access them by design. Cory Mittleider: Yeah.
Yeah, you really can't access it. To your point Allen a lot of the
times what what leaves people to look at them or operators to look
at them is pitch faults. For example, especially electric pitch
turbines, you'll start to see an increase in pitch faults,
asymmetry type stuff or overload over current on electric pitch. Or
I think you mentioned the seals come out, and grease leaks all
over, you'll get dirty blade ruts, and that's a signal you can see
from further away. But you may have some blade bearing health
issues. What we do we and we support in the field. We don't climb.
We don't do the installation removal, but as the bearing
distributors, the bearing experts supporting these operators we'll
get pictures from the field. We'll get a call. What am I looking
at? If they're not used to navigating that kind of external
inspection, we help that way. But when we get I say a new platform
with a new failure mode. We haven't heard of, we'll have them
replace it. We bring it back to our shop in Sioux Falls, South
Dakota, and we'll dismantle it. And I think there's a couple of
those pictures, those dismantling pictures on the website that you
talked about. It's it's a terrible job. It's dirty. That grease is
really sticky, especially electric pitch turbines. That tooth the
open gear grease is really sticky stuff. But you work through it,
you dismantle it. Sometimes they've been locked up such that we had
to cut the bearing in half. To get inside to see it. Other times
we're able to remove the filling plugs, pull the balls out and
rotate the inner ring around. And that still takes half a day to
do. So it's a really dirty process. Then you got to clean
everything after you get it dismantled. But then we put all that
diligent diligence and effort into we're inspecting the rolling
elements that came out, inspecting the raceway, looking for signs
of wear. Or electrification or, what they're called micro pitting
or spalling of the raceways, things like that, that help inform the
updated designs that we are offering to operators that have had
these premature failure problems. Joel Saxum: One thing you talked
about offshore, and this is just a funny note when you were talking
about an extreme cases. We're like, how do they know when it fails?
When does the seal go bad? When does it get enough holes in it? And
you're like, yeah, sometimes you have water that runs into the hub
from the outside, or you got to put, you got to make sure you got
your hard hat on when you get out of the truck, because you might
have pieces of bearing falling down from the top. Cory Mittleider:
So to that point, one of the common problems in the last five or
eight years has been cage failures.