Light -duty three phase voltage generator belongs to electric power system relay protection technical field, especially relates to a light -duty three phase voltage generator. The utility model provides a light -duty three phase voltage generator that volume weight is little, be applied to relay protection secondary circuit. The utility model discloses a switch K3, its structural feature switch K3 one end links to each other with the power input terminal, the switch K3 other end links to each other with self coupling voltage regulator T2's input, self coupling voltage regulator T2's output links to each other with isolation transformer T3's input, isolation transformer T3's output one end links to each other with controlling resistor R14 one end, the controlling resistor R14 other end links to each other with resistance R5 one end, the resistance R5 other end respectively with resistance R6 one end, controlling resistor R10 one end, voltage output terminal UA links to each other.