Overview

The Powerpack is a type of electro-hydraulic actuator that converts a DC electrical signal (4–20 mA) into the motion of a hydraulic work cylinder. It is a proportional positioning type, in which the work cylinder position is proportional to the electrical signal. The Powerpack AJ02/AJ03 is an actuator well suited to refuse incineration plants, sewage treatment plants and similar facilities. Its output shaft rotates, making it suitable for final control elements such as butterfly valves.

Features

• Because it receives an electrical signal and operates hydraulically, it provides high operating speed and large operating force.
• The control section uses a hydraulic servo valve, providing good response, easy maintenance and high reliability.
• An electrical feedback system is adopted.
• Only a power supply for the motor is required. A built-in transformer eliminates the need for an instrument power supply for the amplifier.
• Local manual operation is performed by switching over a selector switch.
• An opening output signal (4–20 mA) is provided as standard.
• The work cylinder, control section and other parts are all assembled inside the oil tank, so there is no oil leakage from fittings and no external piping is required.
• Safety functionsIn the event of an abnormal input signal (too low or too high) or a broken feedback potentiometer wire, the crank arm moves in the safe direction. 
• The direction of the safety action can be changed as required.

Components

The hydraulic section of the Powerpack consists of a current-hydraulic converter (servo valve), hydraulic pump and work cylinder. The cast-iron oil tank compactly houses the work cylinder, pump, crank and feedback mechanism, so no external piping is required. The box on top of the oil tank contains the amplifier and an AUTO/MANUAL selector switch for easy local operation.