Development Story

Developing the Successors to Premium Efficiency IE3 Motors—IE4 and IE5 Class Motors

Preventing Global Warming by Pushing the Limits of Motor Efficiency
—IE4 and IE5 Class Motors

Motors account for over 50% of the energy consumed in Japan, while industrial motors alone make up 75% of the energy consumption in the industry sector. Taking this into account, the Top Runner Program based on the energy conservation law was introduced in Japan, establishing minimum efficiency requirements for industrial motors. In April 2015, sales of three phase induction motors fulfilling the IE3 (premium efficiency) standard started taking off, although the Nidec group started offering their IE3 motors seven months earlier in September 2014. Our entire lineup of IE3 three phase induction motors, stretching from 0.75 kW to 55 kW, is certified by UL, CSA and CE, making global expansion possible. Our future plans for these motors include making them even more cost-effective and promoting replacement of older motors still in use.

The cost of switching to premium efficiency motors is made up for by their lower power consumption. This effect is even more pronounced when the number of motors, or their operating time, increases.

At the same time as we started offering IE3 motors, we also started development of the next generation of energy-efficient products: IE4 compliant super premium efficiency motors. Our IE4 motors use a synchronous reluctance design to attain high efficiency without the use of permanent magnets. A major contributing factor to this is the construction of the rotor. As synchronous reluctance motors rely on changes in magnetic reluctance, they require rotors consisting of salient electromagnetic poles. Our synchronous reluctance motors are built with a laminate construction utilizing segments of electrical steel and barriers impenetrable by magnetic flux in order to achieve the optimal saliency ratio—increasing torque and improving efficiency. Needlessly to say, overall optimization—including stator compatibility, drive circuits and control laws—also contributes greatly to the high torque and efficiency of these motors. Furthermore, as a result of the simple rotor construction, Nidec's IE4 motors are compact, lightweight, inexpensive and highly durable as well.

The saliency ratio is optimized by improving the rotor construction. Our synchronous reluctance motors reach IE4 efficiency through improved stator compatibility.

IE5 levels of efficiency are achieved with permanent magnet-assisted synchronous reluctance motors. These motors are competitively priced—and devoid of supply problems—as they make use of ferrite magnets instead of expensive rare earths. They also inherit the benefits of their IE4 counterparts as they are compact, lightweight and highly robust.

IE5 levels of efficiency are achieved with our permanent magnet-assisted synchronous reluctance motors.

Furthermore, Nidec also develops hybrid induction/synchronous "Super Econo motors" capable of functioning both as induction motors (during start-up) and synchronous motors (during normal operation). These motors are characterized by their ability to operate on commercial power supplies and use inverters for speed control—in fact, a single inverter can be used to control multiple hybrid induction/synchronous motors.

As regulations for industrial motors are getting stricter—not only in Japan but also in Europe, America, China and eventually globally—we leverage our technology and know-how, built up through years of developing drive circuits, to develop and promote the use of even more efficient and environmentally friendly motors.

Developer's Comment

Synchronous reluctance motors—the design that we chose when we developed our IE4 and IE5 compliant motors at our research and development center in Taiwan—outperform existing induction motors (IM) and interior permanent-magnet motors (IPM) in terms of efficiency, price, durability, weight and output range. One of the main advantages of our permanent-magnet free IE4 motors and our rare-earth-free IE5 motors lies in their use of common, inexpensive materials, making them insusceptible to supply-related problems. This advantage will be decisive in avoiding dependency on expensive rare materials in the future when IE4 and IE5 compliance becomes compulsory. Another aim of the development of IE4 and IE5 motors is to expand our know-how and technological capabilities, allowing for even more competitively priced IE3 motors.