Control voltage isolation system for electrical rotating apparatus utilizing fiber optics and associated method

In an excitation system for a rotating electrical apparatus including an input voltage generated in a power system of said excitation system, a control voltage isolation system for generating a control voltage representative of said input voltage in a control system of said excitation system, comprising:

• a. voltage-controlled oscillating means for converting said input voltage into a first frequency signal corresponding to said input voltage, said input voltage having a range of voltages, said first frequency signal having a range of frequencies corresponding to said range of voltages, said oscillating means including offset means for establishing a minimum amplitude for voltage input to said oscillating means, in order that said range of frequencies of said first frequency signal has a minimum frequency which is greater than zero;
• b. conversion means connected to said voltage-controlled oscillating means for converting said first frequency signal into a light signal;
• c. fiber optic transmission means connected to said conversion means for transmitting said light signal;
• d. receiving means connected to said fiber optic transmission means for converting said light signal into a second frequency signal;
• and,
• e. reconstruction means for receiving said second frequency signal and reconstructing therefrom a control voltage in said control system representative of said input voltage.