Iron loss = copper loss energy saving

Hello,

I am in touch with a Japanese person claiming he had invented a power saving device, which can considerably save energy. The savings he is talking about are at the magnitude of 25% up to 50% and even more of the total energy consumed by the motor (3 phase AC motors).

According to the manufacturer, the core technology is based on the physical concept of "iron loss = copper loss". That is, he regulates the voltage and frequency to the motor in such a way that keeps it working at a point in which the two losses, copper and iron, are equal. At this point, the total energy saving is greatest.

The machine had already been sold to a large number of well known companies in Japan, and apparently there is a market to it.

At this point I would like to note, that I am totally aware of the fact that this sounds like a complete bull, yet I have personally tested one machine, performing the measurements myself, and was stunned to find that indeed there was a 30% reduction in the motor power consumption. Also, the energy saving device improved the PF from 0.79 to 0.89.

The measurements were done using a sophisticated instrument, measuring the 3 phases. The saving I got was in KW of course (e.g. not in KVARs). The motor speed was maintained at the original value (1500 RPM), as well as the pressure built by the pump the motor was driving.

Another thing I noticed was that the motor vibrations considerably decreased, as well as its operating noise and its surface temperature.

The motor used in the test is 400 Volt, 60HP, driving a hydraulic pump for cooling water. Loading conditions are constant (the system is in uniform state uniform flow).

The motor initially was not regulated in any way - it was directly connected to the plant power supply.

I intend to conduct yet another test soon, with a smaller motor (30HP) to try and validate my earlier findings again.

Originally I was very skeptical, and the truth is that I am still, but the test that I conducted stands as proof. What worries me the most is the fact that I know that even regular (non high-eff) motors are quite efficient, with efficiencies of 90% and higher, and the fact that only at very light loads does the motor efficiency sharply drop.

Is there a catch? is there a sting here? am I missing something?

Would be very happy to get any comments and light shedding on this.

-Zac.