Western Electric 407A-4, Инструкция по эксплуатации

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AB
the indic�tor reading
(
and water flow
)
increase, contact
P
closes b efore contact E c l os e s .
AB
the indi cation de•
creases , contact E opens before contact P opens .
These c ontacts are of the b rush and commutator type ,
and in this equipment the ir functi on is to control relay S2W.
The c ontacts are adjuste d b efore leaving the factory to give
a spacing equal to 5 per cent of the t otal l inear s cale
length. This spacing should not be reduce d belo.v 1 per cent.
The contacts are protected by means of fuses acces s ible by
removing the front of the instrument. If the contacts be­
come inoperative, ins pect the fuses . If fuses are burned
out, inspect the wiring for short c ircuit or other defect
before replacing fuses .
The Rotax instrument is provided with a thre e-valve
manifold and two vapor traps . The manifold as s is ts in the
installation, checking and servicing of the instrument. The
vapor traps maintain accuracy of cal ib ration when smal l
amounts of air are entrapp e d in the piping between the Rotax
and venturi .
Installation
The Rotax instrument must be rigidly mounted and care­
fully leveled s o that the float does not drag on the s i de
of the float chamber.
To attacn the three-valve manifold and vapor traps :
B low out manifold piping and valves to remove all dirt.
Separate the two unions on the manifold and attach
them to the 1/4 inch nipple and to the tube having 1/4
inch male pipe ends furnishe d loosely with the mani­
fold.
Screw 1/4 inch pipe nipple into top of upper chamber
of instrument, in place of plug .
Screw tube into top of lower chamb er o f instrument in
place of plug.
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