Energy Efficient Electric Motors
Globally, electric motors consume 3/5th
of the all the electricity generated, therefore improving the
efficiency of every electrical motor should be a high priority for
everyone.
But there is more to the story than just efficiency,
optimizing the usage of the electrical motors to met the actual load
provides more opportunities to lower you
operating costs, and lower pollution that electricity
generation creates.
Motor Efficiency
First, we must ask what is efficiency and then what is high efficiency?
We need to ask the question since everyone has a efficient view of
hi-efficiency.
|
5.4.1
Motor Efficiency
Except for motors which are
components of package equipment, any polyphase induction motor having
an output power of 5kW or greater that is expected to operate more than
1,000 hours per year should use "high-efficiency" motors tested to
relevant international standards such as IEEE 112-1991 or IEC 34-2. The
nominal full-load motor efficiency shall be no less than those shown in
Table 5.1.
Table 5.1: Minimum Acceptable Nominal Full-Load
Motor Efficiency for Single-Speed Polyphase Motors
|
|
Motor Rated Output (P)
|
Minimum Rated Efficiency (%)
|
|
5kW<P<7.5kW
|
84.0
|
|
7.55kW<P<15kW
|
85.5
|
|
15kW<P<37kW
|
88.5
|
|
37kW<P<75kW
|
90.0
|
|
75kW<P<90kW
|
91.5
|
|
P>90kW
|
92.0
|
Globally, electric motors consume 3/5th
of the all the electricity generated, therefore improving the
efficiency of every electrical motor provides energy efficiency
improvement opportunities.
But there is more to the story than just motor efficiency,
optimizing the usage of electrical motors such that they met
the actual load requirement
provides other opportunities to lower your
operating costs, and lower pollution that electricity
generation creates.
It is worth repeating that the cost of preventing pollution
(entering the environment) is very much lower than the cost for
remedial work to remove polluants from the environment after
contamination.
This is the p2e2 principal, gain the benefits of energy efficiency,
lower energy biils, and lessen the environmental impact today, before
the cost of remediation hits your profits tomorrow.
Motor Efficiency
The Hong Kong Code of Practice for Energy efficiency clause
5.4.1 Motor Efficiency states:
"Except for motors which are
components of package equipment, any polyphase induction motor having
an output power of 5kW or greater that is expected to operate more than
1,000 hours per year should use "high-efficiency" motors tested to
relevant international standards such as IEEE 112-1991 or IEC 34-2. The
nominal full-load motor efficiency shall be no less than those shown in
Table 5.1.
Table 5.1: Minimum Acceptable Nominal Full-Load
Motor Efficiency for Single-Speed Polyphase Motors
Motor
Rated
Output (Power) |
Minimum
Rated
Efficiency
(%) |
| 5kW<P<7.5kW |
84.0 |
| 7.55kW<P<15kW |
85.5 |
| 15kW<P<37kW |
88.5 |
| 37kW<P<75kW |
90.0 |
| 75kW<P<90kW |
91.5 |
| P>90kW |
92 |
So that is clear right? I am sure I am not alone noticing the
"escape" clause for
package equipment. However, at present the HKCOP for
electrical installations is not complusory.
They is still plenty of confusion in the industry regarding what is and
what is not an energy
efficient motor, partially caused by the standards themselves.
Many
buyers believe that high efficiency motors are fitted as the
"standard" in all equipment, however as indicated above reliance on a
standard for packaged equipment can be deceiving.
Engineers, industry, equipment manufacturers, and specifications
need to avoid these abstract terms like "high efficiency" and actually
state real values.
Electric Motor Applications
Electric motors are ubiquitous,an integral part of modern life, they
are
used everywhere, in most appliances, manufacturing processes,
air conditioning units, fluid handling, and the like.
They are relatively inexpensive when compared to their
operating
cost. Typically, an electric motor will consume enough electricity in
the first nine - twelve of months of operation, exceeding its
initial capital
cost. That's important because operating in-efficient motors every
year after year just wastes energy. Replacing an in-efficient
motors is a sound investment.
Variable Speed Drives and Controls
It is critical to match the motive power to the actual load.Even in
the
21st century, we still see over sized motors wasting energy. Often
motors are running at full speed during periods of part load, where as
this was difficult in the past to control, modern Variable speed drives
can easily lower the operating speed in real time to match the actual
load.
In most applications, including fans, lower the speed lowers the power
consumption significantly, and reduces operating cost due to extending
operation life of the motor.
Further Information
To learn more above energy efficient electric motors and
operation contact Mr John Herbert at our Hong Kong office, telephone
+852 2335 9830
keywords: energy efficient motors, motor operation, high
efficiency
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