ABB”sContracintelligent electric modulating rotary actuator offers 90-degree rotarymovement for such applications as dampers and butterfly valves. Thesecompact actuators are suitable for continuous duty, modulating, orpulse input control. Features include: • Stall-proof without the need for position or torque-dependent switch-off.• Sturdy, oil-lubricated gearing with high mechanical efficiency.• Adjustable mechanical limit stops for defined operating range.• Local pushbuttons and hand wheel for emergency operation.• Configurable microprocessor-based power electronics.• Extensive diagnostics and self monitoring. The actuatorstransfer torque via a lever/linkage bar assembly. Alternatively, theactuator is directly coupled to the driven shaft. A special powerelectronics unit controls the actuator and acts as the interfacebetween actuator and control system. During continuous positioning thepower electronics unit varies the motor torque without stopping untilthe actuator force and the restoring process forces are balanced. Highresponse sensitivity and high positioning accuracy with shortpositioning time ensure control quality and a long actuator life.