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b. The load circuit shall be energized through a bounce free contact from a power supply regulated
to within 5 percent of the specified rated voltage (or current) as shown on figure 10.
c. By measuring the time for the current to reach 63 percent of its final value, the dc inductance is
calculated as:
L = Rt
Where:
L - is the inductance in henries,
R - is the resistance of the load circuit, and
t - is the time in seconds for current to reach 63 percent of its final value.
4.6.19.2.2 Inductive load, ac. The load shall consist of inductive and resistive elements with 0.7
lagging power 0.05 lagging power factor at the voltage and frequency specified (see 3.1).
4.6.20 Life (see 3.22). Unless otherwise specified (see 3.1), relays shall be operated for 100,000
cycles with contacts loaded in accordance with 4.2.3 and 4.6.20.1 through 4.6.20.4 inclusive, as
applicable. Relay coil energization shall be nonsynchronous with the power supply for ac loads. Each
relay case shall be connected to system ground through an individual normal-blow fuse rated at the
greater of 100 mA or 5 percent of load current. The ambient temperature of the interior of the test
chamber shall be +125C minimum. The contact resistance or voltage drop, as applicable, shall be
monitored during 40 percent minimum of each "on" and each "off " period. The monitoring equipment
shall automatically hold the relay under test in the state in which the failure occurs (energized or de-
energized) and the contact voltage shall be removed. All contacts in each sample unit shall switch
identical loads. Following cycling, the electrical continuity of each case-grounding fuse shall be checked.
a. Level I. Relays shall be subjected to 100,000 operations (unless otherwise specified; see 3.1) at
the rate of 20 cycles 2 cycles per minute, with "on" and "off " times approximately equal.
b. Level II. Relays shall be subjected to 50,000 operations (unless otherwise specified; see 3.1) at
the rate of 29 seconds 3 seconds "on" and one and one-half seconds 0.5 second "off ".
4.6.20.1 Resistive load. Cycling rate shall be 20 cycles 2 cycles per minute. Suitable resistors shall
be used. Current shall be rated resistive current as specified (see 3.1).
4.6.20.2 Inductive load. Cycling rate shall be 10 cycles 1 cycle per minute with approximately equal
"on" and "off " periods. Current shall be rated current. Appropriate inductive load components (see
4.6.19.2.1 and 4.6.19.2.2, as applicable) shall be used. A suitable resistor may be placed in the circuit to
obtain rated steady-state current flow. Inductive load testing shall be approved by the qualifying activity
(see 6.10).
4.6.20.3 Lamp load. Unless otherwise specified, the lamp load shall be performed with a 28 V dc
power supply voltage. Either lamps or simulated loads may be used to provide the load as follows:
a. Simulated loads shall subject the relays to making 12 times the rated lamp load and breaking the
rated lamp load. The duration of the 12 times inrush shall be 0.015 second to 0.020 second. The
total "on" time shall be 5 seconds 0.05 second and the "off" time shall be 5 seconds 0.05
second.
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