MOTORING TOWARDS
PLANT EFFICIENCY
If you are a plant manager becoming overwhelmed by motor running costs,
there are some simple steps you can take to stop them running out of control
BY MAREK LUKASZCZYK, EUROPEAN MARKETING MANAGER, WEG
The energy cost to run an electric motor
over 10 years is at least 30 times the
original purchase price. Thankfully,
changes in a plant do not have to be huge
in order to reap savings. Many of these
changes will work with your existing
footprint and equipment.
Straightforward motor upgrades
Many electric motors in use are either low
effi ciency or not properly sized for the application.
Both issues result in motors working harder than
they need to, using more energy in the process.
Similarly, older motors may have been rewound
a few times during maintenance, lessening their
effi ciency. In fact, it is estimated a motor loses one
to two percent effi ciency every time it is rewound.
Because energy consumption accounts for 96%
of the total life cycle cost of a motor, paying extra
for a premium effi ciency motor will result in return
on investment over its lifespan.
But if the motor is working, and has been
working for decades, is it worth the hassle of
upgrading it? With the right motor supplier, the
upgrade process isn’t disruptive. A pre-defi ned
schedule ensures the motor exchange is carried out
quickly and with minimal downtime. Opting for
industry standard footprints helps to streamline
this process, as factory layout will not need altering.
Obviously, if you have hundreds of motors in
Electric motors
are very low
e ciency assets
on the shopfl oor
your facility, it’s not feasible to
replace them in one go. Target
the motors that have been
subjected to rewinds fi rst and
plan a schedule of replacements
over two to three years to avoid
signifi cant downtime.
Motor performance sensors
To keep motors running
optimally, plant managers
can install retrofi t sensors.
With important metrics such
as vibration and temperature
monitored in real-time, built in
predictive maintenance analytics
will identify future problems
ahead of failure.
With sensor-based
applications, data is extracted
and sent to a smartphone or
tablet. In Brazil, one factory
implemented this technology
on motors driving four identical
air recirculating machines.
When the maintenance team
received an alert that one had
higher vibration levels than
the acceptable threshold, their
heightened vigilance enabled
MAINTENANCE SEPTEMBER 2020
them to solve the problem.
Without this insight, unexpected
shutdowns could have arisen.
But where are the energy
savings in the aforementioned
scenario? Firstly, increased
vibration is increased energy
usage. Solid integrated feet on
a motor and good mechanical
stiff ness is crucial to guarantee
less vibration. By resolving
the non-optimal performance
rapidly, this wasted energy was
kept to a minimum.
Secondly, by preventing a full
factory shut down, the higher
energy requirements to restart
all machines was not required.
Install soft starters
For machines and motors
that do not run continuously,
plant managers should install
soft starters. These devices
temporarily reduce the load and
torque in the power train and
the electric current surge of the
motor during start-up.
Think of this as being at a
red traffi c light. While you could
26 www.manufacturingmanagement.co.uk
/www.manufacturingmanagement.co.uk