PRICE ISN'T THE ONLY DIFFERENCE AT ARCO
-- ARCO Expands Condition Monitoring Program --
Carson, CA -- One of the most promising but difficult frontiers for improved business practices is the realm of maintenance and engineering. This is a point that ARCO Products Company's Los Angeles Refinery (LAR) management realized as their net margins decreased in response to increased global competition.
"We had to become more aggressive in seeking ways to reduce
our maintenance and operating costs, so we set forth the
challenge to reduce costs while improving equipment reliability
and availability," said Robert Yontz, LAR's condition
monitoring coordinator.
After these goals were articulated and then communicated within
the organization, the strategies to be used for reliability were
defined. This was a critical step so that subsequent efforts
would be perceived as objective and credible, leading toward
accomplishment of the stated goals.
JUSTIFICATION & IMPLEMENTATION
In 1994, ARCO maintenance management expanded their existing
inspection program by establishing a Reliability Group to
evaluate and support the implementation of reliability
strategies. One of these strategies was to reduce the maintenance
and operating costs on their 2500 motors.
Yontz began researching options in an effort to identify the tools and techniques that would be most effective in achieving their motor reliability goals. With an existing mature vibration analysis program already in place, electric motor testing from a condition-monitoring point of view became a primary focus.
SELECTION AND APPLICATION
After several months of research, Yontz determined that motor
circuit analysis would best meet their needs. The technology he
selected -- The MCE™ Tester from PdMA Corporation --
quickly received its "baptism of fire."
In September 1995, Yontz began implementing the tester at the
refinery. "It was quite a chore trying to prove to the
electrical community that this little machine really
worked," he explained.
The first true test occurred just three months into
implementation on a 2300 Vac, 1250 Hp synchronous motor, which
had failed only 11 months after being placed in service following
rewind. When unit operating personnel conducted a test operation
of the fire suppression deluge system, the motor shut down. The
first electricians on the scene determined that two main line
fuses had opened and appeared somewhat aged. Analog megger
testing indicated 12 MW to ground, which is acceptable for this
voltage application. "The normal approach, before the
tester, would have been to replace the fuses, start the motor and
see what happens," said Yontz.Instead, looking to determine
the true root cause, condition monitoring team members were
requested to conduct an MCE analysis to help determine the
motor's health.
Motor circuit analysis indicated that temperature-corrected
insulation resistance was 3.7 MW, at borderline IEEE minimums and
significantly below preferred reliable numbers of a healthy
circuit. Additionally, circuit capacitance was more than three
times the value of any other motor tested at the site. These two
parameters (low megger and high capacitance), when correlated,
indicate a loss of insulative abilities and imminent failure.
Armed with this knowledge, Operations Supervision agreed with the recommendation to investigate further at the motor. Upon removal of the motor connection box, five of the six feeder leads were found to have insulation cracked through to the conductor at least halfway around the cable. Signs of arcing were both aged and fresh. Water from the deluge had entered the pre-existing cable insulation cracks and allowed A and C phases to ground resulting in a phase-to-phase short.
Finding this failure in its primary state allowed the rewind
vendor to conduct on site repairs in minimal time and under
warranty. If the motor had been started and failed, a rewind
would have been required involving all necessary crafts and time
for the removal and reinstallment of the motor. Moreover,
identification of the root cause might not have been possible at
that point.
The impact was immediate. It cost 60 hours of downtime versus the
35 days for the previous rewind, and 22 craft hours versus the
550 multi craft hours from before. Cost avoidance for the
maintenance effort alone was more than $82,000. Including process
opportunity, ARCO avoided another $260,000 loss for a total in
excess of $342,000 avoided. These are hard bottom-line numbers to
the company.
THE MCE TESTER
Looking back at the decision-making process, Yontz reflects
upon how he selected the MCE Tester, which he first learned about
at an annual PdMA MCE Technical Conference. "The conference
was just what I had been looking for. It was extremely beneficial
to talk to other MCE users and hear their experiences first
hand," he says. "Also, PdMA was very interested in user
feedback to establish and prioritize improvements. That seemed to
be the whole theme of the conference; continuous improvement and
customer value. That's a critical factor in our choice of
companies to partner with in our efforts."
After the conference, Yontz arranged for an independent "test drive" with the MCE Tester. He found after two months of testing that it was a good fit for ARCO's needs. He notes, "It's the only motor circuit tester I found that produces immediate results in the field. That's important because we want tools that promote efficiency. No repeat actions or rework; do it right, the first time!"
Once the independent test drive proved to be a success, Yontz
researched the economics involved. He justified an initial
purchase of two MCE Testers over a 10-year project life with an
18-month payback and a 16 percent return. "As the
application above verifies, we exceeded those expectations well
beyond my original calculations. Reduced downtime, more accurate
work and repair scope and several major 'saves' accounted for a
four-month payback period on the Testers and all the associated
costs, rather than the projected 18 months," he explained.
"I never believed it, I thought the MCE was just an
expensive megger. But now with almost one million dollars worth
of 'saves' I tend to lean toward it," said Jeff Trexler,
electrician. Electrician Freeman Ledford agrees. "In the
past, we only did analog megger tests, now we are much more
thorough. The Tester allows us to do a variety of tests and
stores all the data directly into the computer. There's no need
to go searching for information any more."
Fred Antuņez, Electrical Foreman, said his department uses the
MCE Tester mostly for diagnostics. "The MCE is a tool that
lends credibility to us by providing data which ensures the motor
circuit is okay to operate after a fault. When Rob introduced the
Tester, it took a while to understand the numbers and graphs so
we were hesitant. But once the numbers became familiar to us, the
craftsmen (electricians) preferred it over conventional
testing."
ASSESSMENT
To realize the full potential of a preventive and predictive
maintenance plan, Yontz advises companies that a balanced synergy
between multiple activities must be reached. "It's not easy.
It requires effective project planning, open communications,
teamwork, interdisciplinary training, complete follow through on
recommendations and feedback, reliable data storage and easy
retrieval, correlation and integration across technologies, and
thorough cost-benefit analyses." He adds that only when
everyone understands each specific role and how it fits into the
larger scheme does a new process become institutionalized.
CONCLUSION
As a result of ARCO's interdisciplinary training and applications
efforts, staff across a wide range of disciplines have gained a
better appreciation of the MCE Tester's capabilities and
limitations. The resultant teamwork has not only
"culturalized" their motor circuit condition assessment
process, but it has also decreased their conditional diagnosis
time. Further, it has enhanced prognosis accuracy and speed.
ARCO's Los Angeles Refinery, located in Carson, CA, covers close
to 700 acres and has a crude capacity of approximately 265,000
barrels per day. ARCO Products Company provides petroleum
products for clients in five Western states (Arizona, California,
Nevada, Oregon, Washington) and Canada.
PdMA Corporation, based in Tampa, is a predictive maintenance
company which also offers advanced motor testing, full lubricant
analysis, maintenance program analysis, and predictive
maintenance training.
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