MIL-DTL-19648E
4.7.14.1 Resistive. When the load is specified as resistive ac (see 3.1 and 6.2.1), contacts shall make
and break twice the rated current. When the load is specified as resistive dc (see 3.1 and 6.2.1), contacts
shall make and break 1.25 times the rated current load. Switching rate and ratio of "on" to "off" time shall
be as specified for the life test in 4.7.16.
4.7.14.2 Inductive. When the load is specified as inductive ac (see 3.1 and 6.2.1), contacts shall make
and break two rated inductive load circuits connected in parallel across the power source. When the load
is specified as inductive ac (see 3.1 and 6.2.1), the inductive load component shall be the same as used
in the life test (see 4.7.16) and the series resistance shall be reduced to 80 percent of the value used in
the life test. Switching rate and ratio of "on" to "off" time shall be as specified for the life test in 4.7.16.
4.7.14.2.1 Inductive load component. For contacts rated inductively up to and including 1.0 ampere dc,
a load component of 200 millihenries minimum inductance shall be used. For contacts rated inductively
greater than 1.0 ampere dc up to and including 5.0 amperes dc, a load component of 50 millihenries
minimum inductance shall be used. For contacts rated inductively greater than 5.0 amperes dc up to and
including 10.0 amperes dc, a load component of 20 millihenries inductance shall be used. The
inductance shall be measured on a 60-cycle inductance bridge with approximately 5 volts rms applied to
the inductive load component. The inductance shall be measured with maximum rated dc current flowing
through the inductive load component. The inductive load component shall be air gapped to give
substantially constant inductance over the application range of current. Inductive ac load circuits shall
use a suitable combination of resistive and inductive load to insure that the power factor will be 50
percent at the frequency used. For all dc induction loads from 2 to 100 amperes, approval by the
qualifying activity is required (see 6.9).
4.7.14.3 Tungsten lamp. When the load is specified as tungsten lamp (see 3.1 and 6.2.1), contacts
shall make and break twice the rated load, which shall be composed entirely of tungsten lamps operated
at their rated voltage. Switching rate and ratio of "on" to "off" time shall be as specified for the life test in
4.7.16.
4.7.15 Salt spray (corrosion) (see 3.18). Relays shall be tested in accordance with method 101 of MIL-
STD-202. The following details shall apply:
a. Test condition letter - B.
b. Measurements after exposure - Not applicable.
After test, relays shall be examined for evidence of corrosion; peeling, chipping, and blistering of the
finish; and exposure of base metal.
4.7.16 Life (see 3.19).
4.7.16.1 Life test with specified off time (for mechanical and contact life test). All contacts of each relay
shall be subjected to cycling with nominal coil voltage and rated contact load and voltage (see 3.1 and
6.2.1). The cycling rate shall be determined as follows:
Off time = 6 x normal operate time (N.O.T.) or 300 seconds, whichever is greater.
On time = N.O.T. plus 2 x N.O.T. tolerance.
20
For Parts Inquires call Parts Hangar, Inc (727) 493-0744
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business