Elkhart Brass 70133000 Electric Valves - Manual (Page 6)

6
II OVERVIEW
GENERAL
The EPI2 is an electric quarter-turn actuator suitable to operate a valve or damper.
PRINCIPLE OF OPERATION
The electric motor drives an epicyclical gear train via a spur reduction. The epicyclical gear train has a single
compound planetary gear which meshes with two internally toothed gears, one being the fixed annulus and the
other being the output gear. The fixed annulus gear has external helical teeth meshing with a transversely
mounted worm gear, thus locking the annulus into a fixed position. The worm gear can drive the annulus;
eliminating the need for a declutch mechanism to enable manual operation.
Actuator position is controlled with a position sensor directly coupled to the actuator’s output drive.
ELECTRICAL OPERATION
Clockwise or counter-clockwise rotation may be selected during actuator setup.
An open or close electrical command will cause the actuator to move to the extreme end of travel or to a
partial position.
Control system details are shown in the specific wiring diagram.
MANUAL OPERATION
Manual operation can be utilized when there is no power to the actuator or during initial actuator setup and
calibration. The manual operating device is completely independent of the motor drive and can be operated at
any time (even during electrical operation) without endangering the actuator. The handwheel does not rotate
during electrical operation.
To close the valve, turn the handwheel clockwise.
To open the valve, turn the handwheel counter-clockwise.
If the handwheel is used during electrical operation an alarm is set and the actuator will stop.
Important: The standard direction of rotation for the handwheel is clockwise (CW) to close.