The Wrong Stuff
Shorten Repair Times
NEC at the Facility
Unsafe Confined Entry
Answer to Electrical Troubleshooting Quiz
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e-newsletter is brought to you from the
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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
Managing energy use
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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.
The Wrong Stuff
How do you know if you're not doing the right
maintenance? Some ways to determine this include:
- For each piece of equipment, compare current maintenance
to the manufacturer's current recommendations. Resolve any
- Do a year-to-year comparison of the maintenance logs. If the
breakdowns occur on the same equipment, the maintenance probably is
being done incorrectly or not often enough.
- Examine breakdown causes. Are the root causes preventable?
things such as lubrication issues, insulation breakdown, corrosion, and
loss of connection integrity. None of these has time to cause
breakdowns if you're doing the right maintenance at the right time. If
are causes, you have identified some maintenance
To perform the right maintenance, you need certain
resources, such as:
- General training. Everyone needs training in areas such as
safety, general practices, communication skills, plant systems, and
- Equipment-specific training. Don't rely solely on equipment
manuals if you want an effective maintenance team. Good vendor training
will help you meet your downtime prevention goals.
- Test equipment and accessories. Money spent on test
is almost always well spent. You can delete the word "almost" from your
situation by assessing your measurement needs, and then getting the
equipment and training to meet those needs. The right accessories can
leverage the investment in many different ways, so don't skimp
- Outsourced expertise. For reasons of safety, efficiency, and
getting the job done right, outsourcing certain functions is the only
logical course. Saving money by doing it yourself isn't cost-effective
if the place blows up.
Unfortunately, none of this is free. Some tips on getting the
- Strike when the iron is hot. Suppose Line 3 went down due to
something that maintenance training would have prevented. While it's
down, ask the Line 3 production manager the cost per hour. This
"sweating the numbers moment" is the ideal time to ask that manager
about putting the uptime-making training onto the production budget
rather than the maintenance budget.
- Tie the request to an event. This frames it as an uptime
issue, not a maintenance issue. For example, suppose you want another
handheld power analyzer. Rather than request the funds as though you're
buying general maintenance test equipment, approach it from the
perspective of preventing another revenue loss (name the amount) that
resulted from (name the event).
- Make it someone else's issue. If three production managers
are asking the division vice president to send someone to a weeklong
thermography class, it's no longer "maintenance just trying to spend
money." If you've identified a resource need, explain to others how
benefit if you have that resource. If they want the benefit, they may
feel compelled to make your issue their issue.
The choice "repair or replace" can be misleading.
Unfortunately, it often misleads people into "troubleshooting by parts
substitution," which is never a good practice. It doesn't address what
failed or why. In fact, it's not troubleshooting at all.
Suppose you find that the motor drive output varies and then
this is the cause of the line speed variation. No amount of drive
adjustment fixes this. Does this mean the drive is defective? It would
seem so. Nevertheless, after you replace the drive and set up the new
one, the problem persists.
Do you now have two bad drives? Maybe, but chances are neither is
bad. The entire system (including the drive) may have been out of whack
for a reason that has nothing to do with a drive malfunction. How can
you find that reason so you can make the variations go away?
Repair Times Permanently
Why do professional football players review their
previous games on film? After all, they were there -- how does
again help? It does so by allowing them to examine what they did right
and what they did wrong, and perhaps help them do better next time.
That same technique can be applied to repairs. This "review and
improve" was standard practice in many maintenance departments (like
nuclear generating stations) long before the advent of today's
inexpensive video cameras. Back then, maintenance departments used the
eyes and mind of a work analyst. This person, who typically had an
industrial engineering background, would watch the repairs and then
identify where and how things could be done more efficiently. However,
that person rarely had the electrical background that would allow the
best solutions to emerge.
Football players are the best ones to recommend how to improve their
game. Likewise, the people who do the repairs are the best ones to
recommend how to improve their game. Consider implementing the
video review technique, if you haven't already.
NEC at the
An installation that complied with the NEC when
constructed may later violate it with potentially catastrophic
consequences. The installation may not have changed, but something else
did. An example of this is protecting conductors and busbars from
physical damage in switchboards and panelboards [408.3(1)]. Work
performed inside a switchboard or panelboard can easily result in an
overlooked loss of mechanical protection. Ensure that it doesn't.
Confined Entry Assumption
Never assume that a particular requirement on the
"isn't really necessary." Discuss your opinion with the entry
supervisor. If the permit can be re-issued without that requirement,
fine. Otherwise, it's necessary.
Answer to Electrical
As with any control system, the problem is seldom the
controller. It's almost always an input or a control element. Start
solving this kind of problem by looking at the inputs. For example, is
there a pressure sensor related to line speed? Then, simulate a
"typical" pressure, and watch the signal at various points in the
Also note that inductive coupling is a common cause of control
problems. If a signal wire carrying a millivolt signal runs parallel to
480V wiring, you can get an intermittent "ghost" signal on top of the
desired one, which can easily cause line speed variations.
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