4. The apparatus of claim 1 wherein said electrical energy source means predetermined operating frequency is displaced in spectral location from fundamental and harmonic frequencies of a sixty Hertz power line frequency.
4. The apparatus of claim 1 wherein said electrical energy source means predetermined operating frequency is displaced in spectral location from fundamental and harmonic frequencies of a sixty Hertz power line frequency. 5. The apparatus of claim 4 wherein said electrical energy source means predetermined operating frequency is between two hundred and four hundred Hertz.