Energy saving opportunities in Electric Motor Drive System
Motors use
almost one third of the world’s electrical energy. That means they account for
a substantial part of the total human ecological footprint.
Here are
few suggestions that can help you to save energy in Electric Motor Drive
Systems:
Selecting
Higher Energy-efficient motors
By replacing inefficient motors with premium efficient motors
equates to significant cost savings over the life of the motor, not to mention
the additional benefits of reduced down-time and increased productivity and
reliability.
When purchasing a new motor choose the most energy efficient one
you can afford. Premium efficiency motors cost about 15 to 20 percent more, but
can have a relatively short payback to off-set these costs.
Oversized
Electric Motors
Replacing older, oversized motors with properly sized ones offers
huge energy saving. Select a lower power motor and operate it at a higher load
factor near optimal efficiency to help justify the motor replacement.
Oversized Motors can actually have these effects. 1. Reduced
Efficiency 2. Poor Performance 3. Increased Equipment Cost.
Using Variable
speed drives
Centrifugal loads offer the greatest potential for energy savings
by using variable frequency drives (VFDs) to control speed. The flow is
proportional to speed, pressure is proportional to the square of speed, and Kilowatt
power is proportional to the cube of speed in Centrifugal Loads.
That means if an application only needs 80 percent flow, the fan
or pump will run at 80 percent of rated speed and only requires 50 percent of
rated power.
In other words, reducing speed by 20 percent requires only 50
percent of the power.
So, what a variable frequency drive does is to deliver only the
amount of energy that is needed by the motor for the work being done.
This saves energy- a lot of energy!
Minimizing
voltage unbalances
Voltage
unbalance degrades the performance and shortens the life of a three-phase motor.
Voltage at the motor that is not within the design limits leads to a decrease
in power factor.
Motor
management policy
Having a structured approach to repair and maintenance can save
energy and reduce down-time caused by motor failure.
a. Plan for repairing failed motors, which compares long-term
repair vs. replacement costs
b. A plan for replacement with new and more efficient motors
c. A schedule and procedure for motor maintenance
We
offer free Energy Efficiency Motor Audits with
a report showing payback on investment for each of the applications
audited, showing energy and monetary savings.
