BEARINGS AND SEALS
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STAVE THRUST HORIZONTAL
www.hydroworld.com July 2017 / HYDRO REVIEW 25
the environmental beneft they add.
Smith: Mostly it’s just reduced maintenance. With the greased bushings, our
maintenance personnel have to go out and
grease them periodically. With the self-lubricating bushings, our personnel are not tied up
always having to be mindful of greasing those
and keeping an eye on those. So, it reduces
personnel time and also reduces cost.
Q: In what types of equipment are
you using self-lubricating bearings?
Freeman: We are using self-lubricating bearings in all the mechanisms that operate the
turbine wicket gates, including the wicket
gate stem bushings, gate linkage bushings,
operating ring guide and thrust plate and
servomotor connecting rods.
Barrett: Te main equipment using the
self-lubricating bearing material is wicket gate
bushings and operating ring wear pads.
Tooktoshina: Our primary use for self-lubricating bearings are for wicket gates and wicket
gate linkage bushings. We have also used them
for turbine guide bearing applications in the
past, where they replaced a wood journal.
Drommi: So far, we use the bearings in
guide vane bushings and Kaplan runners.
Smith: We’re using them in our hydro
turbines, typically for our wicket gate shafts,
ports and wicket gate linkages. We have them
in valves and gates, like wheeled gates, for
the bearings on those wheels. As far as the
main bearings for the turbine and generator,
those are typically traditional bearings, like
hydrodynamic or anti-friction bearings.
Q: What are the benefts of using
self-lubricating bearings (e.g.,
reduced use of lubricants, main-
tenance requirements, etc.)?
Tooktoshina: We conduct less maintenance,
from a preventive maintenance point of
view, but also, self-lubricating bearings have
increased life and wear properties. Also,
there is less use of lubricants, which leads to
reduced risk of environmental release. Te
machinability of the materials is also easy, so
we normally keep spares in stock that can be
used for multiple plants.
Barrett: Te beneft of self-lubricating
bearing material is reduced maintenance as
they do not require any greasing. Te main
beneft is the reduced environmental impact.
We have not had them in service long enough
to prove the durability of the bushings.
Freeman: Another beneft is that self-lubricating bushings have lower friction than
greased bronze, meaning a reduction in the
force required to operate the wicket gates. Self-lubricating bushing also have less stick-slip than
greased bronze, meaning smoother operation
and less hunting when positioning the gates.
Drommi: My answer is the same as my
answer to the previous question, with the
addition of the fact that there is lesser friction
Smith: For us it is reduced maintenance.
It’s kind of a hands of. Especially for the type
of application we use it for: components that
are seeing lower loads, lower shaft speeds.
You are not tying guys up dealing with those.
Whereas for the higher load, higher speed, we
typically stick with oil for those.
Q: What results have you seen with
the use of self-lubricating bearings?