Abstract: A pitch drive circuit that operates in an emergency mode, for a wind or water power plant. The circuit has at least one rectifier unit, at least one DC intermediate circuit, two inverter units and a pitch rotary current motor with motor trains that can be contacted on both sides. A first contact side of the motor trains is connected to a first inverter unit and a second contact side of the motor trains is connected to a second inverter unit. At least one switching element is connected to at least one contact side of the motor trains. In a normal operating mode of a first switching state of the switching element the motor trains can be energized via both inverter units, and in an emergency operating mode of a second switching state of the switching element, the motor trains can be energized via a single inverter unit.

Abstract: The invention relates to a pitch drive circuit (50, 52, 54), which can operate in emergency mode, for a wind or water power plant (80), said circuit comprising at least one rectifier unit (14), at least one DC intermediate circuit (18), two inverter units (16-1, 16-2) and a pitch rotary current motor (38) with motor trains (30) which can be contacted on both sides. A first contact side (76-1) of the motor trains (30) is connected to a first inverter unit (16-1) and a second contact side (76-2) of the motor trains (30) is connected to a second inverter unit (16-2). At least one switching element (40) is connected to at least one contact side (76) of the motor trains (30).