A.

Pages 1 - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9 - 10 - 11 - 12

MIL-DTL-38394E

3.4.7 Voltage and frequency. The transmitter shall withstand voltage and frequency

variations from 22 to 30 Vac and 380 to 420 hertz (Hz), or any combinations thereof.

3.4.8 Electromagnetic interference. Unless otherwise specified (see 6.2), the transmitter

shall meet the electromagnetic interference requirements of MIL-STD-461 for Air Force aircraft.

3.4.9 Damping. When the transmitter is subjected to an applied oil pressure sufficient to

produce an indication of 500 psi and the pressure is released from 500 to 100 psi within 0.1 seconds,

the corresponding time required for the transmitter indication to change from 500 to 100 psi shall be

between 3 and 7 seconds. There shall be no damage to the instrument as a result of the pressure

change.

3.4.10 Indicator operation. The transmitter shall be capable of operating either one or two

indicators with size 10 synchros without a change in output equivalent to more than 1 degree of arc.

3.4.11 Pressure bosses and electrical connector. The pressure bosses and electrical

connector shall withstand an applied force of 25 foot-pounds bending movement with no evidence

of damage to welds or soldering, distortion of base plates, and without the calibration shifting out

of tolerance.

3.4.12 Scale error. Scale error shall not exceed the tolerances specified in table I.

3.4.13 Friction and position error. Friction and position error shall not exceed the

tolerances specified in table I.

3.4.14 Effect of lead length. When the lead length (No. 20 American Wire Gauge

(AWG) stranded copper wire) between the transmitter and indicator synchro stators is changed

from 5 to 300 feet, the indication shall not change more than 1 degree of arc.

3.4.15 Case leakage. When a pressure of approximately 0 psi is applied to the exterior

of the transmitter case, the leak rate shall not exceed 0.10 micron cubic foot per hour when

10 percent helium is used in the filling medium and shall not exceed 1.0 micron cubic foot per

hour when 100 percent helium is used as the filling medium.

3.4.16 Sensors matching. The transmitter will remain accurate when pressure is applied

to the vent port.

3.5 Case. The case shall conform to figure 1 and shall provide a hermetically sealed

enclosure for the internal mechanism of the transmitter. Sealing of the case shall be

accomplished so that the seal will not be dependent upon material that would be affected by the

action of any atmosphere to which the transmitter may be subjected.

3.5.1 Filling medium. The filling medium shall be at least 98 percent free of dust particles

and shall contain not more than 0.006 milligram of water vapor per liter (dew point -65 �C) at the

filling pressure. The filling medium shall be either a mixture of 88 to 92 percent nitrogen and the

remainder helium, or 100 percent helium. The absolute pressure of the filling medium in the case

shall be 12 to 14.7 psi.