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MIL-DTL-25971C

3.4.1.12 Transformer. A two-coil isolating transformer shall be provided as a separate

unit in order that the light can be operated from a commercial 60-cycle, 120V source. The

transformer shall have a minimum rating of 50 va and shall be weatherproof. With 120V, 60-

cycle current applied to the primary, and with the specified lamp and lead installed, the

transformer shall supply a voltage of 7 + 0.1V at the lamp. The transformer case shall have at

least two holes for 1/4-inch mounting bolts.

3.4.1.12.1 Fuse. A small fuse, enclosed so that it is waterproof, shall be provided in the

transformer secondary circuit. The fuse shall be rated at 32V, 10 amp. The fuse shall be easily

accessible for changing.

3.4.1.12.2 Primary lead. The primary lead of the transformer shall be 3 feet in length

and shall be permanently connected to the transformer. The cable in the lead shall be two-

conductor, 16 AWG in accordance with SAE AS5756. The lead shall terminate in a two-pole,

parallel blade, attachment plug cap in accordance with W-C-596.

3.4.1.12.3 Secondary lead. The secondary lead from the transformer to the light shall be

20 feet in length, permanently connected to the transformer and shall terminate in a female angle

plug which matches the receptacle on the light. The cable in the lead shall be two-conductor, 16

AWG in accordance with SAE AS5756.

3.4.1.13 Auxiliary lead. An auxiliary lead, 10 feet in length, shall be furnished for

emergency operation of the light from a battery. One end of this lead shall terminate in a female

angle plug which matches the receptacle on the light. At the other end, the cable sheath shall be

removed freeing a 12-inch length of the two insulated conductors. Each conductor shall

terminate in a spring clip capable of being connected to the terminals of a storage battery. The

cable in the lead shall be two-conductor, 16 AWG in accordance with SAE AS5756.

3.4.1.14 Optical. The optical system shall be of the fixed, prefocus type requiring no

focusing by personnel of the operating units. Provisions for making adjustments during

manufacture may be used if the adjustments are rigidly locked in place and will not be disturbed

during routine maintenance. All components of the optical system shall be properly braced and

supported to prevent their getting out of alignment.

3.4.1.15 Wiring. The light shall be completely wired and ready for operation upon

attachment of the poser leads.

3.5 Performance.

3.5.1 Operation. When tested as specified in 4.4.2, the light shall operate satisfactory, all

controls shall work freely, and the color filters and color indicator shall be positioned correctly.

Any sticking, jamming, or malfunction shall be cause for rejection.

3.5.2 Sights. When tested as specified in 4.4.3, the axis of the sight shall be no more

than 1 foot from the center of the target when the target is at 400 feet, or the equivalent of 1 foot

in 400 feet when the target is at another distance.