MIL-DTL-19648E
g. Number of measurements per activation: One to three in each closed contact position. The
readings shall be taken after the circuit has stabilized and within a maximum time of 2 seconds after
activation.
4.7.3.1.2 Contact voltage drop (see 3.13.3). Relays shall be tested in accordance with method 307 of
MIL-STD-202. The following details and exception shall apply:
a. Method of connection: The point of measurement shall be on leads external to the case. Suitable
jigs and fixtures shall be used.
b. Test current:
(1) Normal bridge current if Kelvin bridge is used.
(2) Maximum rated current if voltmeter-ammeter method is used.
c. Maximum open-circuit test voltage - 25 percent of rated contact voltage, or 6 volts, whichever is
lower.
d. Points of measurements:
(1) Between all normally closed mated contacts.
(2) Between all normally open mated contacts.
e. Number of activations prior to measurement: During contact voltage drop tests, the number of
activations prior to measurement is none.
f. Number of test activations: Maximum of three activations in each closed contact position.
g. Number of measurements per activation: One to three in each closed contact position. The
readings shall be taken after the circuit has stabilized and within a maximum time of 2 seconds after
activation.
4.7.3.2 Normal operate time (NOT) (see 3.6.2). Rated heater voltage, as specified (see 3.1 and 6.2.1),
shall be applied until NO contacts close or NC contacts open. The time of operation shall be measured
using a suitable circuit such as shown in figure 1. The timer shall be electronic for time delays specified
as less than 0.1 second. Synchronous motor-driven timers may be used for time delays specified as 0.1
second or longer. The relay shall be at a stabilized ambient temperature of 25°C ±5°C.
4.7.3.3 Operate time and hold in at minimum voltage. The relay shall be subjected in turn, to maximum
and minimum rated temperature. After two hours in each condition and while still being subjected to the
condition, 83 percent of nominal heater voltage shall be applied to the relay heater. The time interval
between application of heater voltage and operation of the contacts, shall be measured. Application of
the heater voltage shall be continued for 15 times normal operate time plus 5 minutes.
4.7.3.4 Release time (when specified)(see 3.6.4).
4.7.3.4.1 Instant release time (see 6.7.7). When specified (see 3.1), the instant release time shall be
measured using generally the same equipment as for normal operate time, keeping in mind that for short
intervals, automatic timing means are necessary. In any event, the heater power shall be cut off
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