4
iMportant
Handwheel rotation
In standard applications clockwise rotation of the
handwheel moves the valve to close position and
counter-clockwise rotation moves the valve to
open position.
Different operation are clearly indicated on the
handwheel.
control unit
local position indicator
Base flange
Mechanical gearing
Manual override
cable entries
terminals enclosure
figure 2
Keystone
ePi-2 quarter-turn electric actuator
InstallatIon and MaIntenance InstructIons
2.4 ManuaL operation
to be used in case of power supply failure or
during actuator setting.
the manual operating device is completely
independent of the motor drive and can be
operated at any time, whether or not the motor
is running, without danger to the operator.
the handwheel does not rotate during power
operation.
to close the valve turn the handwheel
clockwise.
to open the valve, turn the handwheel counter-
clockwise.
if the handwheel is turned during electric
operator, an error will occur and the actuator
will stop. after few seconds the actuator will
restart its operation and move the valve to the
requested position.
2.3 eLeCtriCaL operation
- control command ‘open’: counter-clockwise
or clockwise rotation (selectable on the logic
board) moves the valve to a completely or
partially open position.
- control command ‘closed’: clockwise or
counter-clockwise rotation (selectable on the
logic board) moves the valve to a completely
or partially closed position.
control system details are shown in the specific
wiring diagram.
2. MacHine DescriPtion
2.1 generaL
the ePi-2 is an electric quarter-turn actuator
suitable to operate a valve in a 90° manoeuver.
2.2 prinCipLe of operation
the electric motor drives the input to an
epicyclical gear train via a spur reduction.
the input member of the epicyclical gear
train carries two compound planet gears
which meshes with one internally toothed
gears: the fixed annulus. the fixed annulus
gear has external helical teeth meshing with
a transversely fixed worm gear. since the
annulus cannot drive the worm gear this
provides a fixing point for the annulus, and
since the worm gear can drive the annulus, a
means of manual operation is provided which
needs no declutch.
an end-of-travel-position detection device
is operated via a position sensor directly
linked to the output shaft. the valve position
is continuously monitored in electric mode by
means of a position sensor directly connected
to the ePi-2 output drive.
