Development Story

Resin-Packed Motors

Contributing to Silent Home Appliances with the World's First Resin-Packed Motors

The world's first successful resin-packed motors were launched by Nidec Techno Motor in 1975 as a response to the increasing demand for silent washing machine and air conditioner motors. These motors utilize a structure that takes full advantage of the damping properties of resin instead of using traditional housings made out of steel plates.

Before we could start mass producing these motors, a number of challenges had to be overcome. For example, in addition to molding the bodies of the motors, any gaps in the winding—usually impregnated with varnish—have to be evenly filled with resin as well. Furthermore, great care has to be taken to make sure that the pressure of the resin does not dislocate the internal parts of the motors and lower their performance.

Our resin-packed motors were born from the bold idea of completely replacing the motor housings with resin. Nidec Techno Motor was the first company to succeed with the difficult task of developing a functioning product based on this concept.

At the time, the advanced mold flow analysis technology of today was not yet available, making it necessary to rely on shortcuts such as observing the rate of filling during repeated local injection molding in order to optimize factors such as the shape of the mold, the position of the filling-hole, temperature control, the pressure during injection and the formula of the resin. In 1975, our first resin-packed AC motor was born, and in 1982 we succeeded in creating resin-packed DC motors as well. Since then, we have also been successful in developing resin-packed motors with integrated inverter circuits.

Nidec FDB

One advantage of resin-packed motors lies in their improved heat dissipation—a result of the thermal conductivity of the resin being even higher than that of the surrounding air—which allows for more compact designs. Our recent projects aimed to further improve these motors include designing new magnetic circuits optimized for aluminum windings and integrated circuits, and developing highly efficient and specialized aluminum coil winding machines. We also focus on competitive pricing—paving the way to further expansion into the global market.

Nidec FDB
Our series of resin-packed motors started with small-size products. Since then, it has gradually expanded into the realm of large-size models and has come to include products ranging from 10 w to 1 kW.

The three major advantages we have over our competitors are: our high-quality aluminum windings made possible with specialized coil winding machines developed in-house, our magnetic circuits using ferrite magnets instead of rare earth without compromising on performance, and our propriety "straight core" manufacturing method that allows for efficient use of electric steel while also contributing to lower assembly costs. These advantages are attracting attention both domestically and outside of Japan. At the same time, brushless DC motors—one of Nidec Techno Motor's core competencies—are seeing an upswing as a result of recent power consumption regulations in Europe, setting the stage for further expansion of our resin-packed motor business. Although our resin-packed motors started on the small side of the size spectrum, we have gradually expanded our lineup over the years; currently, these motors come in models ranging from 10 W to 1 KW.

In the future, we plan to develop a wide variety of resin-packed motors suitable for new applications—including water heaters, air purifiers and more in addition to air conditioners and washing machines—with our eyes set on expansion into the European, North American and South American markets.

Developer's Comment

Recently, we have been working on a novel project involving the development of brushless DC motors for washing machines. Brushless DC motors are known for their high controllability, enabling precise sequences of operation designed to negate the noise caused by the water moving around inside the washing machines. This, in combination with the reduced noise of the motors themselves, makes it possible to design very silent washing machines. Energy-efficiency and quiet operation are becoming increasingly important in the world of home appliances, and, armed with assets such as our brushless DC motors and resin-packed motors, we are in a strong position for the future. Although some of our international competitors have entered the resin-packed motor market in recent years, our position as a pioneer and forerunner in the field remains firm. In the future, we hope to continue developing excellent products based on the know-how and capabilities we have built up over the years.