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Crane Repair Case Study |
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November 8, 2005
Modernization of a 25-Ton Whiting Crane
by
Engineered Lifting Systems LLC |
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Engineered Lifting recently
received a request from a customer
to provide a competitive bid to replace “a worn out” 10 year
old Yale FEW model 25-ton hoist.
Another
prospective bidder told the customer that the trolley
and hoist were “worn out”, and it would be better to replace
the entire unit. Engineered
Lifting Systems took a different approach,
looking first at more economical crane modernization rather
than replacement.
An inspection of the Yale
25-ton hoist gearbox showed that all of the gearing
for the 10-year old hoist was in perfect shape. The unit is
a 5-speed hoist with an Eddy Current brake control, and
the hoist was
very noisy. With the
hoist gearing in great condition,
the noise had to be coming from something
else? A bad coupling on the motor shaft was
identified as the noise maker. |
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A worn
coupling on the motor shaft was the noise maker |
The yoke
bearings were worn. The 25-ton hoist gearbox was in
great shape. |
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The
repair of a hoist motor shaft on a hoist
and trolley of this size is a big job to be sure, and
when done completely requires the
gearbox and motor be removed for inspection. So,
the trolley had to be removed
from the bridge and the work completed while the unit
was on the floor.
When we got the hoist and trolley on the
floor, further inspection by Engineered Lifting
Systems with agreement by the
customer showed that some of the money saved to
modernize rather than replace the
hoist and trolley should be spent replacing the 50-year old
Bridge controls, while removing
excess controls, wiring and resistors.
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The 25-ton
hoist and trolley were brought to the floor for inspection
and modernization |
After 50
years of service, the old bridge controls were ready for
replacement |
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The motor
leads and other wiring shows the signs of many years of
maintenance. |
Resistor
banks were ready for replacement with modern crane controls. |
Because of their reliability,
control, and flexibility,
Magnetek’s Electromotive controls
were selected as the replacement of
choice for the old 5-speed magnetic
controls on the trolley and bridge.
Since the 50-year old bridge
enclosures were in great shape, we and
the customer decided to use the old enclosures and
conduit since we were removing most of the old wiring and
controls anyway.
During the hoist motor removal, everyone was shocked to see
the method of termination for the 30-hp motor leads, just
look at the picture above! This
was corrected with wire lugs properly installed prior to
re-assembly, and this was not the
only wiring horror story seen, or fixed.
A small dumpster full of wire was removed from the site,
along with hundreds of pounds of old controls and resistors.
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The old
crane control enclosures were reused, the wire plume,
resistor banks were replaced with >>> |
State of
the technology Magnetek Electromotive controls replaced a
ton of outdated controls. |
The noisy
drive shaft yoke and coupling on
the hoist drive train was replaced
with a genuine Yale part, as were
other assembly parts. The
old hoist rotor shaft was replaced, along
with new motor bearings, brushes and springs
installed by a very competent local motor shop.
After testing,
the motor was reinstalled.
In 10 years of service at this customer's
location, the hoist apparently
never had a proper oil change. The drain plug on the Yale
FEW unit still had the factory paint on it! So
the gearbox oil was drained, and
as 7-1/2 gallons of fresh 85W-140
was poured into the gearbox, I thought I heard the gearbox
make a big sigh of relief? Maybe it
was just my imagination.
The hoist and trolley was re-installed on the crane, new
controls mounted and terminated, clean-up was an on-going
project, and the crane was load tested without any issues.
The work was completed over a three day weekend, with only a
minimal impact to the customer’s production,
within budget, on time, and the
customer now has a better crane
ready to meet the future challenges of its service
life,
which could be many years yet. These older Yale hoists
were built to last.
Crane modernization saved this
customer a bundle of money. If you are thinking about
replacing old, tired or sick equipment, GET A SECOND
OPINION!!!
For more information
about Engineered Lifting's
crane modernization, please
contact the modernization crane doctor
Eric Brown
today. We make house calls! |
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