Nexen EN40-2B 912004 - Manual (Page 4)

(4) FORM NO. L-20097-F-0605
INTRODUCTION
FIGURE 1
Nexen’s EN40 Electro-Pneumatic Convertor converts current input signals into corresponding pneumatic signals.
Normally the “EN40” is used as part of a Nexen Tension Control System, or as an independent Electro-Pneumatic
Convertor, controlled by an external signal from a Process Controller.
EN40 is designed to balance the force of a moving coil with the force of a poppet valve, and amplify the air flow and
pneumatic pressure passing through a fixed orifice by means of the booster relay . Pneumatic pressure proportional
to the electric signal is thus obtained.
When current flows through the moving coil, a downward force is induced proportional to the current value. This
reduces the clearance between the poppet and seat, and back pressure rises. Since back pressure force must
balance with the moving coil force, a back pressure proportional to the current value results (See Figure 1).
This back pressure is too low to be used as an output, but, is used as the pilot pressure for the Booster Section,
which increases both pressure and volume to provide a usable output.
INSTALLATION
NOTE: “EN40” must be mounted vertically within
±15° in a shock and vibration free area. Locate
“EN40” as close to controlled element as possible
to guarantee quick precise control (See Figure 2).
Read this manual carefully. Make use of its instructions
and explanations. Pay particular attention to all NOTES,
CAUTIONS, and WARNINGS to avoid the risk of
personal injury or property damage. The “Know How”
of safe, continuous, trouble-free operation depends on
the degree of your understanding of the system, and
on your willingness to keep all parts in proper operating
condition.
FIGURE 2
WALL MOUNTING
1. Drill two 9/32 diameter holes 4.57 inches
(166mm) apart in mounting panel.
2. Secure “EN40” to mounting panel using Cap
Screws provided in parts bag.
Permanent
Magnet
Moving Coil
Poppet
Seat
Pilot Pressure
Chamber
Booster
Output
Spring
Plate
Fixed
Orifice
Air In
Panel
Bolts
±15°