revision preference src: Large industrial dynamos with series and parallel (shunt) windings can be difficult to use together in a power plant, unless either the rotor or field wiring or the mechanical drive systems are coupled together in certain special combinations. <SEP> tgt: Large industrial dynamos with series and parallel (shunt) windings can be difficult to use together in a power plant,. Either the rotor or field wiring or the mechanical drive systems are coupled together in certain special combinations.