Product Overview

Caution:

Never power the actuator without a spring return linkage attached.

Positioning with Controller

If the sensed media is within the controller’s setpoint range, the actuator can be positioned by adjusting the controller setpoint up

and down. Check for correct operation of the actuator (valve or damper) while the actuator is being stroked.

Go, No-Go Test

1. Apply power to the actuator. The actuator motor should run and the actuator shaft should extend.

2. Remove power from the actuator. The actuator motor should stop running and the actuator shaft should spring-return to the

retracted position.

THEORY OF OPERATION

Refer to Figure-17. The permanently sealed, oil-filled case contains a movable hydraulic piston assembly and an electric

pump/motor for the hydraulic system. The electric pump/motor is powered by the input supply voltage and runs continuously,

generating a fluid pressure which is transmitted to the top of the piston. This fluid pressure creates a hydraulic force which drives

the piston downward. Opposing the hydraulic force is the spring of the valve or damper linkage. When the hydraulic force

becomes great enough to overcome the opposing spring force, the piston translates downward, extending the output shaft.

The pump/motor contains a transformer winding which provides power to the Vdc power supply. The power supply, in turn,

provides power to the transducer assembly. To proportionally position the shaft, first the control signal (2 to 15 Vdc) input is

compared to the shaft position feedback signal, through the actuator controller circuit. Then, the actuator controller circuit emits

an output signal which positions the flapper in the transducer. The flapper opens or closes further to decrease or increase the

hydraulic pressure above the piston, resulting in an upward or downward movement at the shaft.

MAINTENANCE

The actuator is sealed in oil and requires no maintenance.

Regular maintenance of the total system is recommended to assure sustained, optimum performance.

TROUBLESHOOTING

Use the following steps to locate malfunctions:

Oil-Filled Case

Transducer

Assembly

Electric

Motor/Pump

Controller Printed

Circuit Board

Red

Blue

Feedbac

Vdc Power

Supply

Hydraulic Piston

Assembly

To AC Power

Source

Controller

Input

Figure-17 MP-5400 Series Actuators.