Holidays and Maintenance
Electrical Troubleshooting Quiz
Repairs on Critical Equipment
NEC at the Facility
OSHA and Holiday Maintenance
Answer to Electrical Troubleshooting Quiz
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MRO Insider addresses topics such
Working with management and supervision
National Electrical Code® on the production floor
Safety procedures and programs
Equipment maintenance and testing tips
Managing motors and generators
Trends in training and education
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The designations "National Electrical Code” and “NEC” refer to the
National Electrical Code®, which is a registered trademark of the
National Fire Protection Association.
Holidays and Maintenance
While November and December are busy months for
holidays, they are also busy months for the typical maintenance
organization. For many of these organizations, one problem is that each
year seems to hold the same "surprises" as previous years.
If this sounds familiar, assign someone to track this year's
in some kind of software -- such as a computerized maintenance
management system or spreadsheet. Failing that, use pen and paper!
form an action plan to eliminate those problems. You are more likely to
make progress by focusing on the three most irritating ones than trying
to solve all of them at once.
Here's a partial list of typical "annual been there, done that"
problems. Can you identify the solutions that would work in your
- Delays due to locating and stringing cords for temporary
- Security and access delays for contractors.
- Uncoordinated work among crews.
- Only "Jim" knows how to program machines X, Y, and Z -- and we're
all waiting on him.
- Nobody had the key to the... (tool crib, store room,
- Battery was dead in scissor lift.
- Insufficient (tools, parts, materials, filters) on hand.
- Expired test equipment calibrations.
- Breaker setting calculations (or other engineering information) not
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A critical production line stopped because the main
drive motor failed. After replacing the motor and restarting the line,
you try to determine why that motor failed. You turn the output shaft
hand and hear a grinding sound. A closer inspection reveals dried
on the bearings. Was this probably because the lubrication interval was
The answer to this question appears at the end of this
Repairs on Critical
Does your critical equipment seem to incur downtime
often than non-critical equipment? You may not be imagining this. You
may be experiencing the "critical equipment vicious cycle." Here's the
What typically happens when a motor fails? Maintenance replaces the
motor, but doesn't determine the failure mode. Yet, motors fail for a
reason. If that reason isn't addressed, the replacement will probably
fail for that same reason.
- Critical equipment goes down.
- Maintenance tech arrives promptly, begins troubleshooting.
- Production supervisor was apparently expecting Superman.
- Someone pesters the tech every two minutes with questions, demands,
- The tech does a band-aid fix, just to get the equipment running
again until proper troubleshooting can be completed under better
- Now production says, "If it's working, don't fix it."
- The root cause doesn't get identified, much less fixed.
Consequently, the machine breaks down prematurely.
It is normally not as valuable to get critical equipment back online
immediately as it is to get it back online properly repaired.
Normally, the cost of an extra downtime incident is far higher than any
revenue "protected" by incomplete troubleshooting and inadequate
Assess your situation and communicate the value of the proper level
of repair to all affected parties. You can bolster your case by using
actual revenue losses per downtime incident.
Beware - Arc
Pin and sleeve plugs & receptacles can be dangerous if operated under
load. To prevent accidents install Decontactor Series switch rated
and receptacles. They are a UL rated plug, receptacle and disconnect
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Meltric Corporation, call 800-433-7642, www.Meltric.com
NEC at the Facility
The typical facility undergoes many changes over time,
leading to "add on syndrome." You've seen this -- too much crammed
into existing cabinets, making maintenance difficult. This situation
violates 312.7, which prohibits overcrowding of cabinets and cutout
OSHA and Holiday
During holiday maintenance, several conditions conspire
to raise the risk of injury:
Think of other safety compromises that may occur during holidays, and
talk with your crews about them. See what suggestions they have.
Actively work to prevent adding OSHA incident reports to your holiday
- Due to the time limitations, people are tempted to take shortcuts
complete projects in the allotted time.
- With most personnel gone, it's easy to adopt an informal attitude.
"Nobody is here to use this, so why waste time locking it out?"
- Holiday schedules can reduce alertness. During holidays, people
to stay up later and become sleep-deprived. The Sleep Institute has
found that a person who is 20% sleep-deprived has the mental acuity of
someone who is drunk. This is not an easy problem to manage, but making
individuals aware of it ahead of time may help save a life during
Thanksgiving or Christmas.
Motor Starter Contacts
Quality, low-cost electrical contacts for industrial motor starters &
contactors. Repco replacements for Allen-Bradley, ABB, Clark,
Cutler-Hammer, GE, Hubbell, Siemens, Square D & Westinghouse. Also for
GE 100/200/300, CR7006, CR2800, CR2810, CR7 IEC and DS303 series. Large
inventory & application help. www.repcoinc.com
Answer to Electrical
Grease consists of a carrier and a lubricant. The
carrier is the medium that holds the lubricant in place. If the
lubricant is squeezed out by pressure or evaporated out by heat, the
grease "dries up." Most likely, some condition caused excess heat in
If you don't have a thermal history on that bearing, can you
investigate the cause? Yes. You may be thinking, "I'd want to monitor
the bearing temperatures on the new motor. The recent failure is a good
cost justification for installing such a monitor." That's a good
thought, but there's a catch. A bearing high temperature alarm will
you there's a problem, but it won't tell you what it is. You must
determine the source of that heating.
Rather than wait for the new motor to exhibit excess bearing heat,
work now to identify and eliminate all causes of it. There may be
several at once, so don't stop just because you find one. Begin with
these three problems:
There are many other possible causes, but these three are common --
and fairly easy to resolve.
- Voltage imbalance. Even a small imbalance causes a large
in motor temperature. Just because the bearing grease cooked out first
doesn't mean the imbalance isn't damaging the winding insulation.
Consider putting a critical motor on its own branch or feeder
- Misalignment. Even a small misalignment can raise bearing
temperature, especially with heavy loads. If the motor is critical, it
may be wise to hire a specialist to align it with the right tools and
- Bonding. Current flows in inverse proportion to the
resistance of the paths presented to it. In the absence of a good bond,
bearings make a relatively low-resistance path. See the Article 100
definition of bonding.
Show & Events
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- Preparing a Claim: Bolstering Your Case Through Good Project
- Harmonics: Causes, Symptoms, and Remediation Techniques
- Power Outages: Preventive Electrical Designs and Product
- Electrical Power Engineering: Industry Shortcomings and Possible
- MV Cable Basics: Construction, Testing, Ground Fault
- Ten Trends That Will Shock the Electrical Market
- Good Project Management: Enhancing the Bottom Line
- Insulation Resistance Testing
- Short Term, Long Term Energy Storage Methods for Standby Power
- 2007 Construction Market Forecast
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to attending live activities at conference sessions scheduled
the year, you can meet with exhibitors in virtual exhibit halls. Free
access and all the information you need are available at http://ecmweb.com/etradeshow/.
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