The requirement for arc voltage during the opening of a field breaker for large hydraulic generator increases when de-excitation (DE) is performed with a varistor parallel connected to field wingding. In fact, E.M.F of the field winding is required to be higher than the varistor threshold voltage during opening of field breaker. In this paper, the principle of DE with capacitors is introduced. The high voltage produced during DE by the R,L,C series oscillation is used to force the varistor into operation which decreases the opening arc voltage requirement of the field breaker. A simulation is completed to confirm the proper operation of the new DE approach.