Those numbers are certainly big, and
the burden that falls on the gearmotor
industry to be more efficient remains
heavy. So what are companies doing to
lighten the load?
“Gearing is one of the most important
factors,” says Brother Gearmotor
Applications Engineer Juan Avalos on
how to improve efficiency in a gearmotor.
“If you’re looking at a helical
gear versus a spur gear — those two
just have innate differences in terms of
efficiency. If you’re going to use spur,
that’s usually more efficient than a
helical gear. At the same time, helical
has advantages over the spur, such as a smaller size to carry the same amount
of load and less noise. So gearing is
number one for efficiency.
“That’s the gearbox side of it. Then
the other side of it is the electrical motor.
We’re going to be doing the IE3
gearmotor now, so basically it’s just a
difference in the motor construction. It
can handle flux better and the power
factor is a lot better. It’s going to allow
it to draw less actual wattage.”
Over at Groschopp, a manufacturer
of electric fractional horsepower motors
and gearmotors for OEM and distribution
products, Tullar and design
engineer Scott Lundquist have been
working on other ways to increase efficiency.
“We do our best to design for efficiency
when looking at our standard
products or a customer’s specific
design,” says Lundquist. “One of the
first factors that go into that is having
the correct sizing of the gearbox.
I don’t want to get too big or have too
big of gears for the application. If the
teeth are too thick that may bring the
efficiency down. It would have a
very high safety factor, but the efficiency
may decrease a little bit.
Getting that right size of gears in
there that is ideal for the application
is one thing we look at.”
According to Tullar, Groschopp
has an extensive testing process it
goes through in order to maximize the
efficiency of its gearmotors in any given
application.
“We have a program where we test
all of our motors to run continuously
and intermittently, and we check for
power as well as thermal capabilities
of insulation and everything else. Most
motors don’t run continuously. We’re
the only ones that I know of that if you
give me a duty cycle I can tell you what
the thermal of that motor is.
“Here at Groschopp, we have put in
thousands and thousands of hours to
calculate what will be the most efficient
thing for the application.”
Added Lundquist:
“In that case, you’re getting the right
size motor for the right duty cycle. If we
have a duty cycle that is only half a minute
and then is off for 10 minutes, but
it allows us to size our package down,
then that helps efficiency and doesn’t pull as much current. It’s better for the
customer in the end because it doesn’t
cost as much and they’re not putting as
much power through it either.”
The expanded DOE Electric Motor Rule will go into effect on June 1, 2016. It covers electric motors with nonstandard
end shields or flanges, which equates to gearmotors.
- Click image to enlarge
A peripheral concern is what lubrication
is being used, according to Lundquist.
“It’s something we at least consider
when we’re designing gearboxes,” he
says. “We can look at the type of lubrication
that we use, whether it be oil or
grease. We may need to use a type of
lubrication for another reason — customer
requirements or temperature
requirements. But we do pay attention
to the viscosity of the lubrication that
we use and how it affects efficiency.
“We are aware of how much lubrication
is put in the gearbox. We did a
design where we basically filled it up
with lubrication and it was a very high
speed gearmotor. The input speed was
close to 10,000 RPM and when we ran
our test we had too much heat produced
by the gearbox. We ended up
having too much oil in the gearbox.
We were churning the oil in there and
that was increasing heat in there and
reducing efficiency.
“These are all things that need to be
looked at to increase efficiency.”
The Path to Premium
Efficiency
For those possessing the complete
spectrum of human emotion, tragedy
— more so than any other sensation
— often sparks change. True
enough, we’ve arrived at this crossroads
because of multiple incidents of
great distress.
Due to the 1979 oil crisis, the Chernobyl
disaster in 1986 and a worldwide
need for more power, there has been
increased attention paid to energy
conservation awareness over the last
three decades. Here is a brief timeline
of the events:
In 1992 the U.S. Congress, as part
of the Energy Policy Act (EPAct) set
minimum efficiency levels for electric
motors. In 1998 the European Committee
of Manufacturers of Electrical
Machines and Power systems (CEMEP)
issued a voluntary agreement
of motor manufacturers on efficiency
classification, with three efficiency
classes, according to the American
Council of Energy-Efficient Economy.
According to a paper produced by
Siemens entitled “ABC of Motors”, in
1998 CEMEP issued an agreement of
motor manufacturers on efficiency
classification, with three efficiency
classes: Eff 1 for High Efficiency; Eff 2
for Standard Efficiency; and Eff 3 for
Low Efficiency.
In June of 2005 the European Union
enacted a Directive on establishing a
framework for setting Eco-design requirements
for all energy using products
in the residential, tertiary and
industrial sectors, according to the
International Electromechanical Commission,
according to an article run by
ManagEnergy earlier this year. Coherent
EU-wide rules for eco-design will
ensure that disparities among national
regulations do not become obstacles
to intra-EU trade, said the article. The
directive does not introduce directly
binding requirements for specific
products, but does define conditions
and criteria for setting requirements
regarding environmentally relevant
product characteristics and allows them to be improved quickly and efficiently.
It will be followed by implementing
measures which will establish
the eco-design requirements. In principle,
the Directive applies to all energy
using products and covers all energy
sources, the article said.
On Dec. 19, 2007, President George
W. Bush signed the Energy Independence
and Security Act of 2007 (EISA)
into law. NEMA participated in crafting
major provisions on EISA. One of
the most crucial provisions that NEMA
focused on was increased motor efficiency
levels. The Motor Generator
section of NEMA joined forces with
the American Council for an Energy
Efficient Economy to draft and recommend
new motor efficiency regulations
covering both general purpose
and some categories of definite and
special purpose electrical motors, according
to NEMA Premium Motors.
On July 22, 2009, Commission Regulation
(EC) No 640/2009 implementing
Directive 2005/32/EC stated that in the
EU, with the exception of some special
applications, motors shall not be less
efficient than the IE3 efficiency level as
of Jan. 1, 2015. The Directive also states
all motors (from 0.75 to 375 kW) must
be IE3 by Jan. 1, 2017.
And lastly, the Small Motor Rule was
passed in 2014. According to an article
by Chris Medinger that was published
in the December 2014 issue of Power
Transmission Engineering, the rule covers
two-digit NEMA frame single- and
three-phase 1/4 through 3 horsepower
motors in open enclosures. The mandate
is expected to save appoximately
seven quads of energy, reduce $41.4
billion in energy costs and cut 395 million
metric tons of carbon dioxide.
At face value, this all appears to be
an undeniably favorable sequence of
events. Tullar, however, isn’t yet convinced
that premium efficiency is all
it’s promised to be.
“There’s energy efficient washing
machines now,” he says. “Well, it used
to take 20 minutes to wash a load of
clothes and now it takes me an hour. I
don’t know if that’s any more efficient.
Dishwashers use to run 40 minutes
and now they run three hours. Are we
really saving the water or the electricity
that we thought we were?”
Still, initial projections are promising.
Based on U.S. Department of Energy
data, it is estimated that the NEMA
premium-efficiency motor program
would save 5.8 terawatts of electricity
and prevent the release of nearly 80
million metric tons of carbon into the
atmosphere over the next ten years.
That is equivalent to keeping 16 million
cars off the road.
For Tullar and Groschopp, it’s not a
bridge they have to cross — yet. Fractional
gearmotor companies, at this
time, still aren’t confined to any laws
stating that they absolutely must go to
IE3 or NEMA Premium. It will be, as the
saying goes, the last hat to drop, and
Groschopp will be ready when it does.
“We’re waiting to see when the new
laws come out, but have we checked
into the new laminations, building materials
and tested all of that stuff? — absolutely,”
Tullar says. “Do we want to
spend the money to buy new laminations
right now? — probably not.”
Brother, because it manufactures
gearmotors over 1 horsepower and
falls under the law beginning in mid-2016, introduced its first IE3 gearmotors
at Pack Expo Las Vegas on Sept. 23.
According to Avalos, the new gearmotors
offer increased efficiency over
standard IE1 models throughout the
speed range and initiate less mechanical
stress, which directly translates
into long-term energy savings. The
IE3 gearmotors run cooler and with
less noise and, as they are sealed for
life and require practically no maintenance,
reduce costly downtime. Two
of the factors in the enhanced durability
of Brother’s IE3 gearmotors are the
company’s long-lasting e-coat paint,
and increased lubrication through the
use of premium H1 food-grade grease.
Though it’s not an entirely apt comparison
because they’re operating under
slightly different circumstances,
Brother and Groschopp have still presented
us with two different, legitimate
options when it comes to upgrading to
premium efficiency: be proactive and
get ahead of the curve or be cautious
and wait it out. What’s the line in the
sand between the two philosophies?
Well, it’s cost, of course.
“To increase our cost when we don’t
have to yet doesn’t make sense for
us,” Tullar says. “We’re in a very competitive
market. The thing about the 1
horsepower motors and above is that
there are a few people that use them.
For the fractional, the prices are less
and the buyings are higher.”
Now, most gearmotor manufacturers
will fall somewhere between Brother
and Groschopp, and yet there is another,
far less traveled path to be taken: IE4.
Yes, while most of the world is still
making the transition to IE3 and
NEMA Premium low-voltage motors,
some companies have decided to join
Marty McFly in the future ahead of
schedule. IE4 motors, dubbed “Super
Premium Efficiency” motors, have
actually been on the market for some
time, and since 2009 have posted consecutive,
double-digit growth rates and
almost quadrupled in value in 2013
to reach $114.7 million with nearly
259,000 units shipped, according to a
Jan. 20, 2015 article published by www.
automation.com.
So why have some companies surged
ahead to IE4 while others are still spinning
their tires at IE2 or below? Once
again, cost is the obvious culprit.
“It is possible to go to IE4, but it’s
more expensive for the company to
manufacture,” Avalos says. “Therefore,
if it’s more expensive for the company
to make it, it’s more expensive for the
customer to buy it. There’s a big economic
factor there. Everyone has to
have time to do the proper research
and development and weigh benefits
against their competitors.”
At this point, IE4 is the highest efficiency
that has an actual designation.
IE5, according to Avalos, is currently just
speculative. And after that? Who knows?
After all, the clock never stops ticking.
“It’s really dependent on the technology,”
Avalos says of continuously
increasing gearmotor efficiency. “To
get higher efficiency, you’re going to
have to do something different. You’re
going to have to use a new material,
you’re going to have to change the way
the rotors are designed, and you’re
going to have to make something so
there’s less losses.
“Especially at our size of motor, the
changes could be very minimal — like
maybe 1%. If we start getting up into the
bigger horsepower motors, it’s even less
of a change because those are already
so efficient. If you have a 200 horsepower
motor the change could be less
than 1%. Of course, if you want to do
that it would be a really big investment
and the whole company would have to
alter all its motor designs. It will happen
eventually, just not today.”
Tick.
Tick.
Tick.
You hear that? That’s the sound of
change.
And it’s getting closer and closer.
About Author
Erik Schmidt, Assistant Editor, has a Bachelor's degree in journalism from Marquette University. He has a decorated writing history that includes stops at various journalistic enterprises in the Chicagoland area where he covered sports and hyperlocal news. He joined the staff of both Gear Technology and Power Transmission Engineering in 2014..
