Suitable for applications such as dampers and butterfly valves, ABB’s new Contrac intelligent electric modulating rotary actuator offers 90-degree rotary movement. These compact actuators are also suitable for continuous duty, modulating, or pulse input control. Some of the features include: stall-proof without the need for position or torque-dependent switch-off; oil-lubricated gearing; adjustable mechanical limit stops for defined operating range; local pushbuttons and hand wheel for emergency operation; configurable microprocessor-based power electronics; and extensive diagnostics and self- monitoring. The actuators transfer torque via a lever/linkage bar assembly. Alternatively, the actuator is directly coupled to the driven shaft. A power electronics unit controls the actuator and acts as the interface between actuator and control system. During continuous positioning the power electronics unit varies the motor torque without stopping until the actuator force and the restoring process forces are balanced.