8
4
Optional Manual Operation
3.9.2 Spring-Return Adjustment
(Accumulator Fitted)
Speed Control of the spring stroke
is adjusted as outlined in Section
3.9.1.The hydraulic stroke is adjusted
by the Extend needle valve. Loosen the
jam nut and turn the valve clockwise to
decrease stroke time and anti-clockwise
to increase stroke time.
3.9.3 Spring-Return Units for
Positioning Applications
Positioning units will have an additional
speed control labeled Retract Slow.
This is used to slow the spring stroke
as the actuator approaches its demand
position. This will be factory set to
maximize positioning accuracy and
should not need adjusting.
3.9.4 Double-Acting Adjustment
(Accumulator Fitted)
Speed control of double-acting units
is not possible unless a hydraulic
accumulator is supplied.
The speed control labeled NV-EXT and
NV-RET are used to adjust the stroke
time. Loosen the jam nut and turn the
appropriate valve clockwise to decrease
and anti-clockwise to increase.
3.9.5 Double-Acting Adjustment
(No Accumulator)
Speed control is not available on
double-acting units without an
accumulator. This is due to the nature
of fixed displacement pumps.
Optional manual operation may have
been specified for your EH actuator.
For all EH actuators, optional manual
operation is provided with a hydraulic
hand pump. When supplied, a pump
with a removable handle is located on
or near the power unit.
WARNING:
Manual override operation should
only be carried out when there is no
power supplied to the actuator.
Hand pump Operation
In most cases, a two-position lever
on the side of the manifold selects
the direction of travel. Some special
actuators have a ball valve(s) to control
hand pump operation. Consult your
job specific hydraulic schematic for
operation details..
WARNING:
See specific manual override label
as supplied with actuator, for
manual override procedure.
For units fitted with an external
solenoid valve, an extra isolating
valve is fitted inline with the valve,
this must be set to ‘Manual’ to
operate the manual override.
An isolation valve is also fitted for
fail in position actuators, this must
be set to ‘Manual’ to operate the
manual override.
There is also a locking mechanism
fitted to each ball valve to allow it
to be locked in position by means of
a padlock. It is recommended that a
padlock is fitted for actuators being
used in an ESD application.
Operating your EH Actuator
continued
3
