November 24, 2017

4. Reducing the Losses Related to the Core Material

Motor core material is iron based and all iron alloys show a loss in the form of waste heat as the motor operates. This waste heat is a result of the inevitable loss incurred as the magnetic field is alternated in the core. The silicon-iron lamination industry has sought and produced better and lower loss core materials for the past 100 years and these improvements have made better, smaller and more efficient motors. However, the lowest loss material is not conventional silicon-iron, but it is in fact amorphous iron. Amorphous iron is the optimum low loss choice of all materials to use in the production of efficient electric motors.

The advantage of the amorphous iron is that it has much lower core losses than silicon-iron at all frequencies. The amorphous iron advantage increases with ever-increasing frequency. This fact allows the motor designer to design the amorphous iron motor to operate at much higher frequency than for other types of material.

Whereas much of the past century has seen motors designed at 50/60 Hz, recently many silicon-iron designs have pushed to 120 or even 240 Hz. These recent solutions are seeking to reduce motor size and cost per item 3) above, but since they use conventional silicon-iron, they often suffer from lower efficiencies due to the high losses in the silicon-iron core. Amorphous iron, however, has such properties that very low SPP ratios are possible and in fact desirable.