Western Electric 407A-4, Instruction Manual

Page: 37 / 136

age current meter
(MSF)
which indicates the current to ground
through the water.
The s afety devices for the protection of the vacuum
tub es cons ist of an alarm-operating the rmometer
(
TDlF
)
to
warn of the approach of the water temperature to a safe high
limit, and water flow relays
(WDlW
and
W D2W )
which serve
automatically to dis connect the high-voltage supply frcm the
tub e s if insufficient water flows through the tub e j ackets .
The proper flow through the two water cir cuits is controlled
by throttle valves
(Z 3W, Z4W ) .
A pres sure gauge is provided
in the pump room at the low-pressure s ide of each throttle
valve and at the high-press ure side of the cooler by-pass
valve, and the valves thems elves are furnishe d with position
indicators for quick and easy obs ervation and resetting.
The pressures at the entrance to the inlets to the insulat­
ing tubing are indicated on a duplex pressure gauge in the
control unit.
The pumps furnishe d are capab le of circulating an ex­
cess flow of water s o that some throttling is always neces ­
sary for normal operation .
For convenience o f operati on, the indicating flow meter
(WD2W )
in the power-amplifier branch is provided with indi­
cator s cales showing the flow in gallons per minute. Als o ,
in the pump room, there are provided three thermometers , one
(MlW)
to read the temperature of the water being pumped to
the tubes, another
(M2W )
to read the temperature of the
water returning frcm the tubes, and a third
(M3W)
to read
the temperature of the water returning to the reservoir.
For s afety in cold weather, provis ion is ma.de for
automatically draining the outdoor cooling equipment when
the pump s tops .
Various degrees of c ool ing, t o suit weather conditions,
30