A-A-52551 Starter-Generator: 300 Ampere, 28 Volts, Direct CurrentThis CID covers the requirements for a 300 ampere (A), 28 volt (V), direct current (dc) starter-generator, referred to herein as "generator". This dual purpose unit is belt driven with open construction and not submersible. The generator is used on military motor vehicles and on other equipment to start the gasoline engine connected to it and to generate dc energy for lighting, battery charging, and other purposes.

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A-A-52551A

2.3.1.1 Maximum speed. When operated at 28 volts, generator shall produce a maximum speed of 3500 revolutions per minute (rpm) at cut-in (see 6.5), a maximum speed of 3600 rpm at 100 A, and a maximum speed of 4200 rpm at 300 A.

2.3.1.2 Starter output. Generator shall develop the minimum torque specified in table I at

16 volts with 1.25 ohms connected external to the shunt field.

TABLE I. Starter output torque.

* Locked-rotor torque

2.3.2 Endurance. Generator shall deliver rated output of 300 amps at 28 volts for 1000 hours when operated as detailed in table II. During this time, generator shall require no servicing or replacement of parts. Generator shall subsequently meet the requirements of 2.3.1 at the performance checkpoint in figure 1.

TABLE II. Generator endurance schedule.

NOTE:

During the last 100 hours of operation at each step, generator shall be operated with armature shaft at an angle of 45 + 1 degrees above the horizontal for the first 50 hours and 45 + 1 degrees below the horizontal for the second 50 hours.

2.3.3 Overspeed. The generator shall evidence no thrown solder, thrown impregnating compound, damaged insulation, raised armature windings, raised commutator bars, or other damage when operated with an open field circuit at a speed of 7150 rpm for one minute. The generator shall subsequently meet the requirements of 2.3.1 at the performance checkpoint in figure 1.