Koso REXA Electraulic Xpac, Installation And Operation Manual

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REXA
Electraulic Actuators & Drives
Xpac
Installation Manual -- Version 5.1 (5/98)
S-3
S. SURGE CONTROL OPTION
High speed operation in one direction during upset conditions can
best be handled with the
REXA Surge Control Option. The standard
actuator is augmented with three additional components:
Mechanical Spring - provides the force to move the actuator
in the surge direction.
Solenoid Bypass Valve - bypasses the actuator’s normal
hydraulic circuit. Requires fast response, high capacity and
zero leakage.
Solid State Relay - interfaces the PCP with the solenoid.
The PCP will pulse the solenoid through the electronic relay to al-
low controlled high speed motion in the spring direction. Spurious
operation is prevented by the inclusion of a Surge Breakpoint (SG)
parameter in the SEtUP menu. If the change in control signal is
less than the Surge Breakpoint, the actuator operates normally. If
the change in control signal is greater than the Surge Breakpoint
(and in the surge motion direction), then the solenoid opens and
the actuator is moved at high speed to the new position.
Various configurations of the spring package may have been pro-
vided. The spring may be installed to open or close the driven
device. Loss of power failure position can either be lock in place
or in the surge direction.
Complete details can be obtained in Application Note #4, Surge
Control Option.
INSTALLATION
The fast response solenoid is a 3-way configuration and piped
external to the hydraulic cylinder. An adjustable needle valve is
in line with the solenoid to allow custom adjustment of the surge
speed to meet a particular installation. Depending upon the failure
on loss of power (in place or in the surge direction), the solenoid
will be piped either Normally Open or Normally Closed.
The wires used for the surge solenoid are in place of the normal
internal failure solenoid (blue pair of the module cable). Connection
for the solenoid within the control enclosure is made directly to the
Surge Auxiliary Board located on top of the PCP.