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1 Jul 2018

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.

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