Energy Efficient Motors:When Is The Right Time To Replace Old Motors?

Posted by Jimmy Hovey on Fri, May 04, 2012 @ 08:05 AM

Save Your Company Money With Energy Efficient Motors....But You Need To Plan Ahead!

Choosing the Right Motor Requires A Planenergy efficient motors how to plan a efficient replacement strategy

When a motor goes bad, you rarely have time to consider all the options that you should consider before purchasing a new motor.  You likely are in a position that requires immediate action. 

With a little bit of planning, you could create a long term motor replacement plan that will identify the best, most efficient motor for replacement.

You Have To Inventory What You Have

Survey your motors. Gather nameplate information and obtain field measurements (voltage, amperage, power factor, operating speed) under typical operating conditions. Initially focus on motors that exceed minimum size and operating duration criteria.

The initial criteria typical selection criteria include:

• Three-phase NEMA design B motor

• Non-specialty motor

• 10 to 600 hp

• At least 2000 hours per year of operation

• Constant load (not intermittent, cyclic, or fluctuating)

• Older or rewound standard efficiency motors

• Easily accessible

• Has a readable nameplate.

Conduct a motor replacement analysis.  You can do this yourself with software such at the US Department of Energy MotorMaster+ Software program.

After you analyze your facility, you can create your motor replacement strategy with the following 3 three categories:

1. - Replace NOW

Motors Offering Rapid Payback through Energy Savings, Improved Reliability, or Utility Rebates.

These include motors that run continuously (typically 8000 or more hours a year), are currently inefficient (including over sized motors), must be reliable, or are covered by attractive utility rebate programs.

Order an efficient replacement motor soon and install it at the next available opportunity, such as during a scheduled downtime.

2. - Replace WHEN it fails

Motors with Intermediate Payback. When these motors fail, you will want to replace them with an energy-efficient model.

Now is the time to contact motor dealers to review the efficiency and prices of available motors. After identifying the most cost-effective replacement model, you must decide whether to purchase it and keep it on hand as a spare, or wait to purchase it until the existing motor fails.

This choice depends on how quickly an energy-efficient motor can be obtained through suppliers, how quickly a failed motor must be replaced, and how many motors of the same size and type are used in your facility.

3. Don't Replace, Leave AS IS

Motors with Extended Payback. These motors are already reasonably efficient or are used less than 2000 hours each year. They can be rewound or replaced with a similar motor.

Motors and Drives Last A Long Time, Don't Forget To Review

Motors and drive systems have a long useful life. The cost of running a motor may increase significantly in the future.

Energy efficiency improvements that are not justified today may become worthwhile in a few years, so periodically reevaluate paybacks and reliability. It is also important to operate your motor efficiently.

Other Factors To Consider To Maintain Reliability and Longevity

Want to maximize the life of your motors? Here are 2 questions for you to consider;

How Is Your Facility Power Quality?

Address power quality problems. To improve motor reliability and efficiency, it is important to maintain the correct voltage and phase balance, identify and eliminate current leaks, and prevent harmonics in the electrical supply.

It is a good idea to have an electrical motor specialist review the electrical system periodically, especially before installing a new motor or after making changes to the system and its loads. Consult the manufacturer before installing any motor under conditions of poor power quality.

Do You Schedule Periodic Maintenance?

It is important to maintain motors according to manufacturers’ instructions. Although energy-efficient motors with higher temperature-rated insulation may be able to handle higher temperatures and other abuse, there is no reason to reduce maintenance.

Motors should have good ventilation and be periodically inspected for increased vibration or power supply problems.

Learn More About Energy Efficient Solutions For Your Business

Knowing what energy efficient technology makes the most sense for your facility can be an overwhelming task to figure out.  You may think, "but it's just not worth it!". 

You may be right, but how will you ever know without doing some research and planning. 

We created a FREE ebook to help you understand the benefits of an energy efficient solution for your business.  Download by clicking on the book cover below:


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Topics: energy efficient systems, energy efficient, energy efficient motors, energy efficient solutions