Koso REXA Electraulic Xpac, Installation And Operation Manual

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Xpac
Installation Manual -- Version 5.1 (5/08)
4
REXA
Electraulic Actuators & Drives
1.1 Actuator
The heart of the actuator is the Electraulic Power Module. Consisting
of a motor, gear pump, flow match valve (FMV), make-up oil reser-
voir, heater and bypass solenoid (spring fail units only), the Power
Module delivers oil at a nominal 2000 psi to a hydraulic cylinder.
Four different size modules, B, C, ½D and D, are available. The
functional difference between the sizes is strictly pumping volume
and thus, the maximum stroking speed of an actuator. The only vis-
ible difference is the motor.
Figure 1.B
There are three types of hydraulic cylinders. On smaller size linear
actuators (thrust of 10,000 lbs or less and strokes of 6 inches or less),
the cylinder is manufactured from a solid block of aluminum. Larger
size linear cylinders are made of a fabricated tie-rod construction.
The third type, used on rotary and drive units, is a rack and pinion
rotary design. An inherent requirement with the Flow Match System
is equal displaced oil volumes on both sides of the cylinder. This
allows oil movement without an active reservoir. Double rod con-
struction on linear units and opposed cylinders on the rotary units
meet this criteria.
To provide position information, a feedback assembly consisting of
a resistive film potentiometer and a transmitter (4-20 mA) circuit
board is used. The feedback assembly is sealed in a NEMA 4X area
and mounted within or adjacent to the cylinders. The connection of
the potentiometer is by direct mechanical means to the output shafts.
Shock loading and vibration has no effect on readings and lost mo-
tion in the rotary rack and pinion is eliminated.