Relays conforming to this specification are intended for use in dc or ac (single or polyphase) electrical systems as a means of timing and controlling the making and breaking of circuits for electrically operated equipment and devices. Their principal areas of application, such as aircraft, missiles, spacecraft, and ground support equipment, does not preclude the use of these relays in other military applications. Time delay relays covered by this specification are intended to be able to operate satisfactorily in military systems under the following demanding conditions: Operating temperature range of -70°C to +125°C; 1,100 g's of shock; and reduced susceptibility to corrosion in salt water environments. These requirements are verified under a qualification system. Thermal time delay relays are excluded from this specification. The following caution statements apply:

a. The use of any coil voltage less than the rated voltage will compromise the operation of the relay.

b. Transfer relay contacts should not be used to ground load in one position and to 115 V terminal in another position. Transfer relay contacts should not be used to transfer load between phases, nor between unsynchronized ac sources.

c. Pick-up, hold, and dropout voltages are for test purposes only and are not to be used as design criteria.

Contact rating.

The contact ratings of relays covered by this specification are based on load endurance tests which establish the relay capability to switch rated loads. For the purposes of this specification, contact load ratings are defined as follows:

a. Low level: 10 μA at 50 mV to 10 mA at 6 V.

b. Intermediate: 10 mA at 6 V to 100 mA at 28 V.

c. High level: Above 100 mA at 28 V.