New Danfoss VLT® Decentral Drive E cient, reliable and powerful

UK industry ‘is not managing
its electric motors effectively’
NEWS
ABB IS WARNING that much of British industry is not
managing its electric motors correctly and is
rewinding too many old motors, rather than
replacing them with more efficient new models. This
is costing it millions of pounds in terms of
unnecessary downtime, repairs and energy usage.
ABB says that the problem is highlighted by the fact
that the motor repairs industry in the UK is now
worth more than twice as much as the £70m market
for new low-voltage industrial motors.
While acknowledging that mechanical repairs, such
as bearings and shafts, will always be needed, ABB
argues that too many motors are being rewound
automatically.
Steve Ruddell, manager of ABB’s UK motors
business, believes that the reason for so many
rewinds and premature failures is a lack of awareness
among end-users of the need to create motor
management plans. “It appears much easier when a
motor fails to have someone collect it, rewind it and
reinstall it,” he says. “But what if this is a critical,
continuous-process application? Taking it offline
could cost hundreds of pounds per hour.
“Some industries are better than others,” he adds.
“The pulp and paper sector, for example, tends to
have a policy that if any motor is running for more
than 4,000 hours per year, it will be replaced
automatically by a high-efficiency motor at the point
of electrical failure. Any motor below 75kW,
irrespective of running hours, is automatically
replaced at point of electrical failure.
“No one should be making inferior motors today,”
Ruddell continues. “The technology and materials
used by today’s motors gives them an expected
lifespan in excess of 20 years. They should be durable
and highly reliable. Yet many repairers have motors
Rudell: a few small steps can
lead to significant leaps
less than five years old on their
benches for rewind, alongside older
motors having had multiple rewinds.
“It is analogous to the car industry,”
he suggests. “Today you rarely see a
rusty car and very rarely see cars
breaking down. Technology has
improved the reliability and lifespan of
cars, and the same is true for lowvoltage
motors.”
To encourage better motor
management practices, ABB has
launched a scheme called
MotorAdvantage, designed to reveal
the true cost to a company of running
its electric motors. The scheme
includes a site visit by a motor
engineer who assesses the installed
motor base and identifies up to five
motor-driven applications with the
potential for further analysis.
The scheme also assesses the user’s
motor failure policy and its financial
implications, identifies potential
improvements to this policy and
stockholding, and determines the
energy use of the current installation.
According to Ruddell, a motor
management plan can pay for itself
within weeks, if not days, by
preventing unplanned outages.
“MotorAdvantage aims to elevate
motors from being a hidden asset,
with an out-of-sight, out-of-mind
maintenance approach, to an asset
that can earn you real financial
rewards immediately,” he says. “Our
job is to re-educate the market into
the enormous savings that they could
be making from this asset.
“We want to show industry that a
few small steps can lead to significant
leaps in a plant or process
profitability,” Ruddell continues.
“Normally motor management plans
are overly ambitious, trying to assess
every single motor on a plant.
“If it is more cost-effective to rewind
a motor, we will advise of that action,”
Ruddell emphasises. “Our role is no
longer just about making motors – we
need to help companies manage the
ones they have in place more
effectively.”
www.abb.co.uk/energy
Stuxnet virus targets Vacon inverters
THE LATEST REVELATIONS about the
Stuxnet virus suggest that it contains
code that can alter the operation of
frequency inverters from the Finnish
drives-maker Vacon and from an Iranian
supplier called Fararo Paya, thus varying
the speeds of motors they are controlling.
Eric Chien from the anti-virus specialist
Symantec says that although his
company had previously discovered that
Stuxnet modifies PLC code in a potential
act of sabotage, it had not been able to
determine its exact purpose or target.
However, its latest findings indicate
that Stuxnet targets industrial control
systems containing drives from at least
one of the two vendors, as well as the
previously identified Siemens S7-300
CPUs and CP-342-5 Profibus modules.
The virus requires the drives to be
operating at the relatively high frequency
of 807–1,210Hz. When Stuxnet finds the
specified inverters operating at these
speeds, it changes their output
frequencies and thus the speed of the
motors they control for short intervals
spread over periods of months, thus
disrupting the processes being controlled.
Chien points out that drives with
outputs above 600Hz are regulated for
export by the US Nuclear Regulatory
Commission because they can be used
for uranium enrichment. Earlier reports
have suggested that Stuxnet might be
targeting centrifuges used by Iran as part
of its nuclear programme.
If the drives continue to run at high
speeds for a period of time (about 13
days), Stuxnet hijacks the PLC code and
begins modifying the drives’ behaviour.
Over a period of months, it changes their
output frequencies to 1,410Hz for short
periods, and then to 2Hz and 1,064Hz.
This “essentially sabotages the
automation system from operating
properly,” says Chien. Other parameters
may also change, causing unexpected
effects.
Details of Symantec’s latest findings
are contained in an updated version of its
White Paper on Stuxnet. It has also
created a YouTube video demonstrating
how Stuxnet can hijack PLCs.
http://goo.gl/YwTZC
www.drives.co.uk November/December 2010 3