Taking Control of Motors
How much do motors cost a typical institutional or commercial facility? Consider this: A motor is at work behind every fan, pump and compressor. According to a recent report by the U.S. Department of Energy (DOE), motors and drives account for 36 percent of the primary electric energy usage in institutional and commercial facilities.
Savvy decision-makers are paying more attention to motors, especially as electricity prices increase. There is great potential for improving efficiency and increasing savings by replacing failed motors with NEMA Premium motors and considering adjustable-speed drives in appropriate applications. There is also an opportunity to realize savings by ensuring that motors operate as efficiently as possible, and that future repairs or replacements occur with minimal downtime. These priorities are best addressed with a motor-management plan.
By exploring components of a motor-management plan and key sources of support, maintenance and engineering managers can take important steps in improving the bottom line through sound motor management.
Policies and Practices
A motor-management plan is a set of ongoing policies and practices that help facilities manage their motors more effectively by making important motor-related decisions ahead of time, thereby reducing motor energy costs and equipment downtime.
A facility’s motor-management plan can range from simple rules of thumb to a formal set of comprehensive policies. The first step is to consider which building blocks make the most sense for a particular facility. It is often easiest to start with a simple plan, but over time, the plan can grow if desired.
The building blocks include:
REPAIR AND REPLACE POLICIES. When a motor fails, a manager’s priority is to get it running again. Determining a facility’s repair and replace decisions ahead of time can take the panic out of this crisis situation. If a plan is in place, managers can breathe easier knowing that the most cost-effective motor is available or that there is time for a best-practice repair.
Managers need to tailor their repair and replace decisions to facility needs. For example, some facilities set a horsepower breakpoint policy, wherein technicians replace all failed motors below a pre-determined size with NEMA Premium motors. They perform a life-cycle cost analysis for motors above that size.
As noted in the Electrical Apparatus Service Association’s (EASA) Guide to AC Motor Repair and Replacement, repair and replace decisions also might take into account run hours, predicted downtime, repair costs, and other considerations.
A repair and replace policy might be either a general guideline or a formal policy. Either way, when managers set such guidelines, it is critical to share them with key facility staff. One way to convey the policy is to tag the motors in the facility, identifying whether to repair or replace upon failure. This step lets everyone knows what to do when a motor fails.
PURCHASE AND REPAIR POLICIES. When a new motor is called for, it is wise to consider not only the purchase price, but also the lifetime operating costs as well. That’s because energy accounts for up to 95 percent of the total cost of owning and operating a motor. Many facility managers are unaware of that fact.
To minimize these energy costs, consider installing NEMA Premium motors where appropriate. In most situations, these motors are cost-effective. While the initial cost of NEMA Premium motors might be higher, the simple payback — the amount of time required to recoup the incremental cost difference through future energy savings — often is two years or less. And the savings continue to accrue for the life of the motor. But in instances where run times are short and the load is small, using a NEMA Premium motor might not be cost effective.
When motor repair is indicated, quality is important. Creating a policy based on best-practice repair can help ensure motor efficiency and reliability. By establishing a good working relationship with a local service center representative, managers can draft a repair policy that minimizes motor losses to factors such as stator load, friction, and stray load. EASA has developed a host of tools for service providers as well as guidelines for repairs.
Does this effort sound like a major investment? Remember, managers who make decisions now might save downtime later and avoid being forced to live with a costly decision for the rest of a motor’s life. Spending time now can save money later.
PREDICTIVE AND PREVENTIVE MAINTENANCE. A comprehensive motor-management plan may include both predictive (PdM) and preventive maintenance (PM) to minimize unexpected motor failure and to ensure motors operate as energy-efficiently as possible over their entire service lives.
PdM uses technologies and equipment to measure and track the performance of motor components. Vibration, temperature, voltage, current and resistance are all important indicators. It also is important to perform periodic electrical tests on a motor’s windings.
Proper analyses of motor-performance data can indicate which motors are likely to fail, as well as why and when. This understanding empowers managers to make adjustments, repairs or replacements on a relaxed time frame with minimal interruption to operations.
While a PdM plan can aid in avoiding unanticipated failure, a PM plan can help motors operate as smoothly as possible for as long as possible. Simply put, motors run best when maintained in good operating condition. A PM plan begins immediately upon installation, when technicians verify the proper footing, speed and alignment of the motor. Thereafter, a PM plan works to minimize the three primary dangers to motors — heat, dirt and moisture.
The motor service provider can work with managers to draft PM and PdM plans that are right for your facility. With maintenance plans in place, managers can greatly reduce the frequency of costly motor failures.
Inventory and Tracking
Motors often hum away unnoticed, causing some managers to underestimate the number of units actually in operation. So it is important for managers to inventory the motors throughout their facilities. A motor survey involves cataloging relevant information, such as the type, size, age, and repair history.
Managers also might note run hours and other operating conditions. It is not necessary for technicians to survey every motor on the first pass. They might begin by focusing on critical motors first and building a more comprehensive inventory over time.
Performing a motor survey might reveal that several applications use the same kind of motor — information that can simplify future stocking decisions.
With an accurate list of motors, managers then can begin tracking their performance. Motor tracking creates an up-to-date database that can help managers predict and preempt equipment failure.
Facilitywide commitment and understanding are critical assets in the long-term success of any motor-management plan. Gaining support from upper management might require clarifying the financial benefits of sound motor management.
When possible, enlist others early in the planning process. From developing an overall approach to writing specific policies, the entire process of working with technicians, top management, purchasing personnel and other interested parties can help ensure long- term commitment and overall success. When facilitywide commitment exists, managers can be confident that someone will be on hand who knows just how to handle a crisis situation.
Along the way, managers also might call on the expertise and support of motor sales and service representatives. They can be strong business partners and allies in developing a plan tailored to a facility. Motor distributors also might offer support services.
The local utility or other energy-efficiency program administrator also can be a strong ally. These publicly funded programs might offer technical, educational or financial support for motor management and other energy-efficiency projects.
A sound motor-management plan empowers managers to prepare for what is down the road, from energy costs to equipment failure. Whether the first step is a simple plan or something more comprehensive, the important thing is to get started. It is never too late to plan ahead.
Jenny Harvey — (617) 589-3949, extension 226 — is the industrial program associate for the Consortium for Energy Efficiency — www.cee.org — which manages the Motor Decisions Matter Campaign on behalf of the campaign sponsors.