MIL-S-62549 Semitrailer, Low Bed, 40 Ton Nominal Payload For Transportation Of Heavy Engineer Construction Equipment, M870A2This specification covers a level frame, low bed semitrailer equipped with a folding gooseneck for front loading and movement of heavy engineer construction equipment.

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MIL-S-62549(AT)

3.4.15 Reserved.

3.4.16 Electrical.

3.4.16.1 Lighting system. The lighting system shall be 12 volts (V) direct current (dc) with all associated components and shall comply with FMCSR Part 393 and FMVSS 108. The system shall include no less than two composite lights as specified in MS52125-1. Lights and reflectors shall be recessed or guarded to protect them from damage during normal operation of the semitrailer. All wiring shall be properly routed and secured to protect against snagging or tearing. Lights and reflectors shall not be mounted on vertical surfaces of the rub rails or semitrailer bumpers. All electrical wiring shall conform to SAE 11292 using minimum 14 gauge wire.

3.4.16.2 Blackout lighting. The light emitting diode (LED) blackout stop and marker shall operate on 24 V. The emission of any vehicle light source, which may be illuminated in the blackout mode, shall be limited to the visible spectrum, 380 to 700 nanometers. No energy shall be emitted in the 700 to 1200 nanometer portion of the electromagnetic (EM) spectrum. Emission peaks shall not be more than 1% of the peak emission in the visible spectrum. Turn signals and clearance lights are to be inoperative during blackout mode.

3.4.16.3 Receptacle system, 12-24 V. The semitrailer shall be equipped with one 12 contact receptacle with cover, and one 7 contact receptacle with cover installed at the front of the semitrailer. The 12 contact receptacle shall conform to MS75021-1 and be equipped with a cover assembly conforming to Drawing 7731428, nut grommet, retainer conforming to

Drawing 7723309, and grommet, electrical connector conforming to Drawing 7722333. The

7 contact receptacle shall conform to SAE 1560 round socket for an intervehicle connector cable. The 12 contact receptacle shall be provided with necessary components to each circuit to reduce the voltage of a tactical military design truck tractor from 24 V to 12 V shall be connected through the necessary resistors into the 12 V semitrailer circuits as follows:

a. Not used

b. Connect to Circuit Number 3 c. Not used

d. Connect to Circuit Number 1

e. Connect to Circuit Numbers 2 and 6 f. Not used

g. Not used

h. Connect to Circuit Number 5 i. Not used

J. Not used k. Not used l. Not used