8 Things You Need to Know About Retrofitting Motors

“The DuraPlate is a self-contained unit that uses a shaft-driven pump and cooling plate where the oil circulates through to reduce temperatures,” Quackenbush says. “Most other small, power dense products on the market require electric fans, cooling tubes or air to cool the oil, which need some external source of energy. Our DuraPlate is a green technology because it doesn’t require any additional power source.”

But Franz warns that even with a highly efficient gear drive, it’s important to properly install it to avoid energy loss.

“Improperly installed gear drives can result in twisted housings or misaligned couplings, which rob energy from the application and turn it into heat,” Franz says. “Ultimately, the inefficiency resulting from improper installation or maintenance will result in a shorter life of the gear drive and the entire system itself.”

If a motor is already properly sized and running with the right gear drive for the application, the decision to retrofit with a new NEMA Premium Efficient motor may be the best option to increase efficiency.

5. Devise a retrofit strategy

Donaldson-Torit’s Kiolbasa recommends targeting your retrofitting budget based on the motor’s age and run-time hours. He says any equipment installed before 1997 is a red flag that the motor’s efficiency is lower than what’s currently available, but if it was manufactured after 1997, it’s likely comparable to the current EISA mandate and the ROI shrinks.

Equipment that runs nearly 24 hours/day or more than 2,000 hours/year is another indicator that retrofitting may be economically viable.

Scott Hudson, account manager for Siemens, based in Munich, Germany, suggests incorporating a replace and repair strategy based on horsepower.

“Companies may find that implementing an internal energy-efficiency policy helps them standardize their decision-making process,” says Hudson. “For example, they might apply a policy stating that every motor over 25-hp that needs repairing will be replaced with a Premium Efficient one.”

Interstates’ Post recommends a similar strategy.

“Generally, my rule of thumb is if you have to replace a motor due to failure, replacing it with a Premium Efficient one is a wise move because it pays off over the life of the motor,” says Post. “But it’s hard to justify the payback of taking a totally operational motor and replacing it with a more efficient one. If a replacement opportunity presents itself, go with the Premium Efficient, but don’t make it a company initiative to replace all of your current motors. It will take much longer to see an ROI with that approach.”

The highest returns generally come from retrofitting motors that are 100-hp and above in applications that are constantly running, such as fans, mills and conveyors, explains Kiolbasa.

“For example, according to NEMA standards, a 5-hp motor before 1997 had an efficiency of 86%, while the Premium Efficient level is 90.2% efficiency,” he says. “If that motor runs 16 hours/day for five days/week, 52 weeks/year, the Premium Efficient motor will save $89.89 annually — assuming the cost per kilowatt hour is 10.7 cents. The ROI in this case may take a number of years. However, applying the same circumstances to a 100-hp motor, where the pre-EPAct efficiency was 93% and the Premium Efficient level is 95%, you’d save roughly $750 in only a year.”

6. Examine total cost of ownership

The initial purchase price of an EISA-compliant motor compared to an EPAct-compliant motor ranges from an additional 10% to 30%, according to Kiolbasa.

However, lifetime cost analyses used by Siemens show that the initial purchase price represents only 3% to 4% of the total cost of ownership. A majority of the remaining cost is the energy it consumes, justifying the higher purchase price.

Brett Renken, account manager for Siemens, says many in the grain industry are beginning to see the value in purchasing Premium Efficient motors.

“In the oil and grain handling side, the decision has increasingly skewed toward retrofitting new EISA-compliant motors as opposed to repairing or rewinding old motors,” says Renken. “In the past, they leaned more toward the rewind option because of the lower capital costs, but today more companies are looking at cutting operational costs long term.”

Again, visiting MotorMaster+ or contacting your motor sales representative will help determine the lifetime cost of ownership of a particular motor model number.