Woodward 3171A, Руководство по эксплуатации продукта, Страница: 14 / 47

EM35MR1/3171A Gas Valve Manual 26731
4 Woodward
See Figures 2-2 and 2-3 for overall dimensions, installation hole locations, and any
fitting or plumbing connections. Installation attitude does not affect valve/actuator
performance.
Make sure that adequate room is allowed for required wiring and that the wiring
and valve/actuator are accessible for service.
There is an overboard drain port on the 3171A valve (see Figures 2-2 and 2-3). The
drain is to be plumbed to an area outside the turbine enclosure. The drain vents the
cavities between the inner and outer seals on both ends of the valve shaft.
DO NOT plug the drain port. This can cause pressure to build up in
the vent cavity and potentially damage the valve.
EXPLOSION HAZARD—The overboard drain port vents process fuel
to the atmosphere. Vent the drain ports to a safe location away from
the turbine enclosure or any hazardous location / explosive
atmosphere. Protect the vent line from obstruction, physical damage,
condensation, or corrosion.
EXPLOSION HAZARD—The overboard drain gas volume increases
as temperatures drop below 0 °C (32 °F). Plan the vent system, taking
temperature affects into consideration.
It is recommended that the end of the drain line (outside the
enclosure) be placed in a small container of clean, lightweight oil to
check for gas leakage. This will also prevent a corrosive or salt air
atmosphere from corroding the shaft bearings which are in the cavity
between the shaft seals.
Electrical Connections
Shielded Wiring
1. All shielded cable must be twisted conductor pairs with either a foil or a
braided shield.
2. All signal lines should be shielded to prevent picking up stray signals from
adjacent equipment.
3. Connect the shields as shown in the plant wiring diagram (Figure 2-5). Wire
exposed beyond the shield must not exceed 50 mm (2 inches). The other
end of the shield must be left open and insulated from any other conductor.
4. Do not run shielded signal wires with other wires carrying large currents.
5. See Manual 50532,
EMI Control in Electronic Governing Systems , for more
information.
Installations with severe electromagnetic interference (EMI) may require shielded
cable run in conduit, double shielded wire, or other precautions. Contact
Woodward for more information.