two-phase three-wire system

two-phase three-wire system

[′tü ¦fāz ′thrē ¦wīr ′sis·təm]
(electricity)
System of alternating-current supply comprising three conductors, between one of which (known as the common return) and each of the other two are maintained alternating difference of potential displaced in phase by one-quarter of a period with relation to each other.