|
|
EC&M E-Tradeshow
Introducing the EC&M
E-Tradeshow
EC&M magazine's new online tradeshow and
conference series is now open! Use it as often as you like at no cost
to you. The E-tradeshow is a 3D exhibition where you can examine some
of
the latest in electrical products, meet with exhibitors, and gather
information. Plus, you'll be able to attend conference seminars inside
the E-Tradeshow throughout the year. Just click
here and you'll be connected to detailed information about how
to get inside and make full use of the E-tradeshow. In minutes you'll
be
exploring in the 3D environment, be visiting in our charter exhibitors'
booths, and checking out some very cool products.
See you in the show!
ADVERTISEMENT
 Fix Equipment Problems Faster with
C-more!
12-inch C-more machine operator panels are among the
easiest to use in the industry. The Event Manager logs alarms and send
email messages to multiple addresses based on alarms, changing tag
values, periodic events, or even particular screen changes.
C-more...learn more at http://c-more.automationdirect.com.
Maintenance
Maintaining the Motor
Environment,
Part Four
"Shake, Rattle, and Roll" was great for Bill Haley and
the Comets. But if you want your motor to rock around the clock, you
must pay attention to what it's sitting on and how it's fastened in
place.
- Industrial motors may be face-mounted or foot-mounted. In either
case, torque the motor mounting bolts per the motor spec sheet. Store
this torque spec in the repair instructions, not in your maintenance
procedures.
- "Retorquing" properly tightened bolts reduces their clamping power
because it results in overtightening. With motors, it also distorts the
mounting flange (face-mounted) or feet (foot-mounted).
- Use a fastener marking product to visually indicate where a bolt
and
nut align when initially torqued to spec. During normal preventive
maintenance, you merely need to look at this marking to see if the
bolts
are still tight. If the line is broken, disassemble, replace the
lockwashers, and re-assemble. Don't re-use split-ring lockwashers, as
they lose significant spring tension with each use.
- Typically, a foot-mounted motor bolts to an adjustable (e.g.,
slotted) metal base. A base with a long service life may be
experiencing
metal fatigue -- and consequently flexing when it shouldn't. This may
be the source of "mysterious" vibration.
- The base bolts to a cement pedestal (similar to the way a house
bolts to its cement foundation). The pedestal can crack, so inspect for
this.
- Consider the pedestal part of the motor system. When doing
alignment, don't assume it never moves. Over time, the normal shifting
and settling of the building can move the pedestal and cause
misalignment.
- If mounting hardware fails, the base may shift on the pedestal, or
the motor may shift on the base. Follow the mounting hardware tips
outlined above.
- Monitor for vibration to detect early misalignment. With large
motors, misalignment can progress rapidly into catastrophic
destruction.
- If you encounter recurrent cases of excess vibration with the same
motor, you probably have an inadequate pedestal or base. If you're
unfamiliar with how to properly size and construct these, outsource the
work to a qualified firm. This will save time and money, while averting
downtime.
ADVERTISEMENT
A Better Way to Connect Electrical Equipment
Decontactors are a UL rated plug, receptacle and disconnect switch in
one device. With Decontactors installed electrical equipment quickly
can
be quickly connected or disconnected - up to 60hp, 200A. NFPA 70E and
NEC code compliance is simplified because a safety shutter prevents
unintentional access to live parts and 100 kA short circuit ratings
protect users in fault conditions. Click below to learn more and to
request literature or a free sample.
www.meltric.com
Repair
Electrical Troubleshooting
Quiz
Even after three laser alignments, a motor continues to
exceed vibration limits. What is the most likely cause? Or is there
just
one?
The answer to this question appears at the end of this
newsletter.
Replacing Explosion-Proof
Motors
You may have a hard time finding an exact replacement
for an explosion-proof motor. In many cases, machine builders use a
limited production motor -- rather than one you're likely to find in
stock. So you must order a replacement, having it built to the original
specifications and then certified.
But what if an explosion-proof motor fails on a critical production
line, you have no spare, and there's a five-week lead time on getting a
certified replacement?
You know a motor shop that can build (and document) a replacement to
the OEM specs in less than 24 hours. They work with explosion-proof
motors all the time, but they aren't a factory-authorized repair center
-- so they can't certify that particular motor.
From an engineering standpoint, there is nothing wrong with using
that uncertified motor. But there are those pesky legal issues....
You must pass this risk management decision up through the chain of
command; it's not one you can make. Management may decide to use
the uncertified motor until you obtain and install a certified motor.
Be
careful to provide a complete picture of the issue, so the decision is
senior management's -- not yours.
ADVERTISEMENT
Exclusive TightSight™ Display Helps Set a New
Standard
for Clamp Meters.
They're packed with features and like nothing you've ever seen before.
When we began designing the line, we certainly started at the bottom
and
worked our way up. The innovative TightSight™ display gives you a
level of testing freedom and safety beyond any test tool on the market.
In tight, dark or bright locations, it's invaluable. Other features
like
a high voltage indicator will ensure that you've never felt safer.
Visit
www.idealindustries.com
for
a preview of the 600A and 1000A clamp meters from IDEAL.
Operation
NEC at the Facility
Article 300 applies to all of the wiring in your
facility. Part I addresses wiring 600V or under, and Part II addresses
wiring over 600V. Article 300 violations are fairly common. Just as an
example, have you ever seen public address (PA) system wiring draped
over raceway? This installation violates 300.11(B). If you were to
inspect a given area of your facility for Art. 300 violations, you
might
be surprised at how many you find.
The Practical Implications of
OSHA
The Code of Federal Regulations contains 29CFR, which
is
where OSHA regulations reside. And it's massive -- 29CFR contains
dozens of Parts, such as 29CFR1901 or 29CFR1990. Those last four digits
are not date stamps -- they are just how the Parts are numbered. The
Parts break down into Subparts. Part 1926, interestingly enough, has 26
Subparts (A -- Z).
You don't need to know all of these regulations, but you do need to
know, understand, and conform to your company's written safety plan.
Your company is responsible for ensuring this plan satisfies OSHA
requirements. You are responsible for following that plan.
Even a company safety plan can seem intimidating, and all of us are
subject to forgetting things. One helpful technique is to schedule two
recurring appointments (e.g., every Tuesday morning, every Thursday
afternoon) just for reading from the company safety manual. Bookmark
where you left off, and pick up again there on the next appointment.
You
may spend only 20 minutes a week reading tidbits, but the combination
of
frequency and focus will make you an expert.
ADVERTISEMENT
 Carhartt's Flame-Resistant Twill Shirt
Carhartt's flame-resistant twill shirts are available in khaki, medium
blue and dark navy. This shirt has an ATPV of 8.2 and meets hazard
risk
category two. Premium construction offers double-stitched shoulders,
and
a shaped shirt tail for increased mobility. All Carhartt FR can be home
or industrial laundered and is guaranteed to be flame-resistant for the
life of the garment. www.CarharttFR.com
Quiz Answers
Answer to Electrical
Troubleshooting
Quiz
There is more than one likely cause. We've already
addressed problems with the base and pedestal, so you know to check for
those. But you want to avoid going through the expense of upsizing
these, only to discover that didn't solve your vibration problem.
Assuming alignment checks out, here are some things to look at before
looking for pedestal and base problems:
- Motor mounting. "Soft foot" is the most common cause. If you
look carefully at the feet, you'll see distortion, due to
overtightening. Replace the mounting hardware and torque properly to
solve this problem.
- Motor shaft. Use a dial indicator to check for shaft
runout.
- Motor bearings. Motor in-place testing for bearing problems
is not always conclusive. Ask a motor shop for advice for your
particular installation.
- Power. Power anomalies between phases may be driving the
motor into vibration. Use a power analyzer to see what you have.
- Load. If possible, turn the load with portable turning gear
and check for runout with a dial indicator. Also look at load mounting
devices.
|
You are subscribed to this newsletter as #email#
For questions concerning delivery of this newsletter, please contact
our
Customer Service Department at:
Customer Service Department
EC&M
A Prism Business Media publication
US Toll Free: 866-505-7173
International: 847-763-9504
Email:ecmweb@pbinews.com
Prism Business Media
9800 Metcalf Avenue
Overland Park, KS 66212
Copyright 2006, Prism Business Media. All rights reserved. This article
is protected by United States copyright and other intellectual property
laws and may not be reproduced, rewritten, distributed,
re-disseminated,
transmitted,
displayed, published or broadcast, directly or indirectly, in any
medium
without the prior written permission of Prism Business Media.
|
|
