etetananend
ie
"Satan
iestonia
si
portico
‘. "ennarraatesbata,
B.6.3
Control System
The control section (see Figure C.11) consisting of the timer
switch, the timer motor, the 6-volt motor power supply, the 4S-volt
photo initiator power supply, and the photo initiator chassis is
mounted in the center section of the gage. The components are mounted
on spaced metal disks.
The unit is held in place in the gage with set
screws, and is readily removed through the rear of the gage.
The action of the gage can be initiated either thermally or
photo-electrically. The thermal switch and the phototube are located
on the rear chember and are connected to the control section through
f-pressure--sealed connectors. The thermal switch is held displaced by a
fyfusible link which fails at about 155° F, Parallel with the thermal
id switch is a locking relay which is closed by photoelectric action.
\-chrrent flow of 400 micro-amps through the tube closes a sensitive
A
“relay,which in turn closes the locking relay, providing a closed
eirenit for the drive motor and the electrically parallel timer motor.
An afjustable cam on the shaft of the timer motor opens a normal-closed
microgwitch, stopping both motors after any predetermined running time
of fram'o t9.20 sec.
B. 6. if
pretfehnary Shock Tube Tests
\
In ‘the development of the "q" gage a series of tests were run
at the BRL shock tube to. determine optimum dimensions and damping of
the orifices.
wee i s:ha covered static pressures from 3 to 30 psi.
Various sizes of ce
,
~ pressure orifices, damped and undamped,
and varying quantities
‘damping material in the static and stagnation pressure ae tested.
From these tests, it was concluded
that optimum result; vould be obtained using a stagnation pressure
inlet of 1/4 inch dir¢iter with a 3/16-inch-diameter choke 1/2 inch
long in the nose, with37)-
in glass wool damping in the static
pressure inlet and no dampingjmaterial in the stagnation pressure
inlet.
B.7
B.7.1
CALIBRATION OF PRESSUR
General
I
Ss
Since all pressure caunennd.fo
ven in a given range, were not
identical, a static calibration was required for each.
Each scratch
calibration in the form of a group of "flags" was recorded on an
aluminized glass blank as used in the p
pressure gage.
The element was mounted ina fi
e withthe recording blank,
To insure good response from the diaphraga, e cpobew element was
. exercised by epplying the rated pressure about 10 times.
Stylus
pressure was adjusted to a pre-established noyadand & gasket leakage
check made at rated pressure
The pressure
cuum steps Were then
applied to the element and the fixture manipulated
odute the flag
calibration.
If
The record was read with a precision mors =" dee
‘nrdoa calibration curve similar to Figure B.2 was drawn for e’.
mh oe
Calibra-
62