MIL-DTL-23659F
APPENDIX A
(I1iu /I2iu)/(I1t/ I2t).
Therefore, MNFV for the intended-use fireset is equal to the product of the MNFV for the
test fireset and the safety factor.
The MAFV may be similarly computed using the same scaling factor. The test firing unit
components shall not be used beyond their life ratings (e.g., spark gaps rated for forty discharges
shall not be used more than forty total times). Test firing units should be calibrated before the
first test to assure the discharge properties are acceptable, and the subsequent discharges
monitored for changes, such as signs of component deterioration or short circuits.
A.5.2 Electrical Cook-Off Tester, AC. A special test set is required. The test set must be
capable of being controlled to RMS output potential of 440 VAC at frequencies from 50 to 60
Hz; further, the test set must be capable of delivering current without loss of power during the
course of the test sustaining a short circuit current through the ILI for five minutes. The output of
the tester must be controlled to switch voltage on within 10% of the peak voltage value, with a
controlled turn on transient.
A.5.3. Maximum Allowable Electrical Sensitivity Firing Unit. The firing unit for the
electrical sensitivity tests shall be defined by the following:
a. The high voltage capacitor shall have a capacitance of 0.1 µF - 0% + 20%.
b. The diagnostic component in the test set shall be calibrated and may be either a current
viewing resistor (CVR) or a current viewing transformer (CVT) or both.
c. The high voltage switch must demonstrate a wide dynamic range, be extremely efficient,
and must be reproducible shot to shot. Additionally, the switch used should be linear to within
5% when peak current is plotted against charge voltage for discharges of the firing unit
(ringdowns) across the voltage range to be tested. The voltage range tested shall include a
minimum of 5 discharge levels equally spaced across the voltage range. High voltage vacuum
relays, semiconductor switches, and shock switches are acceptable as long as they consistently
deliver a minimum of 90 percent of the capacitor energy into a 0.5 ohm load.
d. Two loads shall be used to evaluate the test set. A short at the output connector and low
inductance resistor of 0.5 ohms shall be used to represent the range of dynamic impedances of
the ILI.
e. A schematic of the Capacitor Discharge Unit (CDU) is shown in Figure A-1.
f. A minimum of three ringdowns shall be performed at two voltages (500 and 1000 volts)
using each of the loads and shall meet the requirements for the parameters listed in Table A-2 as
defined in Figs. A-2 and A-3.
g. The minimum circuit inductance shall be no less than 15 nano Henries and no greater
than 35 nano Henries.
A.5.3.1. Performance. The performance of the test set when shorted at the output connector
is illustrated in Figure A-2. The parameters of interest are defined in the figure and their
required values are listed in Table A-2. The amount of energy delivered to the load and the rate
that it is delivered during the first half cycle of a capacitor discharge are measures of importance
for ILI response. These parameters are defined in Figure A-3 and their required values are listed
in Table A-2.
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