A modified class-G linear amplifier has been developed to improve the overa
ll efficiency of a transconductance amplifier loaded with the high inductan
ce and low resistance typical of the magnetic bearing coils. A simple theor
etical characterization has been used to provide some diagrams to optimize
the power efficiency as a function of a nonconstant load such as that due t
o a rotor unbalance. Experimental results are reported that show a more tha
n satisfactory agreement with the expected results and the developed theory
.