Increase Efficiency With Motor Savvy
EP Editorial Staff | October 1, 2021
The equipment you choose directly impacts operation efficiency and your bottom line.
By Philippe de Gail, Regal-Beloit, and Glenn Martin, Motion
Motors drive virtually every facet of a production line or facility, from conveyors, air handlers, and pumps to mixers, compressors, and hoists. Imagine if you could scale back the electric usage of all those motors while maintaining or improving their reliability. Doing so, however, is not always straightforward.
So many considerations can make important motor-selection decisions challenging, with long-term cost savings and reliability as leading factors. How can manufacturing professionals sort all the options and make effective, informed decisions?
Match features to applications
While matching the appropriate applications with the correct products remains critical, equipment selection becomes equally important, depending on the environmental conditions or market type. For example, an IP69K washdown motor is designed to be exposed to frequent washdowns, common cleaning/sanitizing chemicals, and high humidity, particularly in the food industry.
IP69K washdown motors provide the highest level of durability and flexibility to help maximize reliability and reduce overall operating costs in applications where general-purpose motors will not survive. With constant exposure to high-pressure sprays and harsh chemicals, the slightest opening could lead to motor damage or bacteria buildup. Manufacturers now design washdown motors to be more watertight than ever with these features:
• fully encapsulated internal epoxy insulation
• extreme-duty two-piece shaft seals
• components made from the highest-grade stainless-steel components.
Other extreme environments also require careful motor selection. For example, motors used near ovens or furnaces may require a higher ambient-temperature design to resist the heat. Corrosive environments, particularly those containing sand, gravel, and dirt, use severe-duty motors or motors that meet the IEEE 841 standard.
No matter what the application, properly size the motor to realize maximum efficiency. This entails confirming sufficient torque and speed for the application while including a small safety factor, typically 10% to 20%.
Permanent magnet vs. induction
Ongoing development of new materials and designs keeps pushing motor efficiencies to higher levels. Newer technology such as permanent-magnet alternating current (PMAC) provides significant energy savings. PMAC motors are more efficient than NEMA premium-induction motors and deliver twice the torque of traditional induction motors. These motors obtain efficiency ratings two to three indices higher than NEMA premium motors, while also meeting or exceeding the European Union’s proposed IE4 standard. This is especially true when varying the motor speed in an application.
PMAC motors operate 43% more efficiently than NEMA premium-induction motors and are quieter. Noise-level management is helpful when personnel are near the equipment. In addition to its higher-efficiency capabilities, PMAC motor mechanical design is smaller than equivalent NEMA premium HP (horsepower) models, providing space savings. The extra space permits more airflow in retrofit situations, thus increasing reliability. PMAC motors can deliver significant energy and cost savings, particularly when they replace multiple older motors.
VFDs, also known as variable-speed drives, are increasingly used because they offer better control of production processes. In plants today, more than 80% of new motor installations use VFDs to control performance. Benefits include precise speed and torque control, improved performance and process control, and increased efficiency.
When installing VFDs, additional considerations can help improve motor life and application efficiency. For example, using VFD-rated cabling between the VFD and motor is highly recommended. This cabling can extend motor life and avoid facility electrical issues. Shaft grounding rings installed on the motors help protect them and connected machinery from voltage spikes due to the VFD PWM (pulse-width modulated) waveform.
Another technology that manufacturing facilities use to increase operational reliability is early failure detection. Many devices are now available that mount on existing machinery and process equipment to detect increasing heat or indicate unusual temperature changes. The devices typically communicate wirelessly through Bluetooth, Wi-Fi, or radio frequency. The ability to predict a problem allows the end user to address an issue during a scheduled maintenance period instead of shutting the equipment down in the middle of the night. These devices are often referred to when end users are looking for IIoT solutions, because the information they gather can be shared in cloud-based systems and securely accessed if desired.
Updating older equipment and installing new high-efficiency components typically results in significantly increased energy and process efficiency. For example, a high-efficiency motor and VFD can successfully replace a fan or blower with damper-controlled air flow or a centrifugal pump with a flow-control valve. These motor/VFD conversions are well known for the energy savings they provide in variable-torque applications and for increased process-control efficiency. Even replacing an older AC motor with a newer high-efficiency unit and a VFD can improve reliability in variable-speed constant-torque applications such as conveyors and extruders.
Install it right
Proper equipment installation, whether you’re purchasing new or updating, is critical to a successful solution. Mounting, wiring, and commissioning are key to ensuring that the new equipment operates properly. For example, when installing a new motor and VFD, improper installation and termination of the recommended VFD cable can reduce equipment life and cause premature motor and VFD failure.
Solving the efficiency puzzle
How you equip your plant affects not only operational efficiency but also your bottom line. Selecting the correct equipment is one piece of the overall puzzle. Proper installation and maintenance also contribute to the total picture, affecting process control, equipment life, and downtime reduction. Involving qualified resources such as product vendors and distributors with the appropriate technical expertise can aid the decision-making processes of selecting, purchasing, and installing the correct products. Following these suggestions, while not all inclusive, will start you on the path to positive results and long-term cost savings. EP
Philippe de Gail is a National Account Manager for Regal-Beloit Corp., Beloit, WI (regalbeloit.com). He has 35 years of experience in the electrical product industry.
Glenn Martin is the Automation/Electrical Specialist for Motion (motion.com) in the South Texas District. He has developed and worked with variable-speed drives, electric motors, and automation products for more than 40 years.