22.214.171.124 Low and high temperature storage. The starter-generator shall
operate satisfactorily after having been stored at temperatures ranging from
-62°C to +93°C.
3.7.2 Maximum speed for regulation. The starter-generator, when operated
as a generator, shall be capable of delivering rated voltage at no-load, at not
less than 9,000 revolutions per minute (rpm) with no more than 35 ohms in the
external field circuit.
3.7.3 Minimum speed for regulation. The generator shall be capable of
delivering full-rated load at rated voltage, continuously, at the minimum
speed for regulation (4,400 rpm) with an external resistance in the shunt-field
circuit of 1.25 ohms minimum and not more than 8 amp field current. At 3,800
rpm the generator shall be capable of delivering 75 per cent rated load at 26V,
using a voltage regulator conforming to MIL-R-6809 or MIL-R-23761.
3.7.4 Heating commutation and minimum speed. The generator shall be
capable of meeting the operating conditions specified in 4.6.4. The required
resistance external to the shunt field when operating at the minimum speed,
while the generator is hot, shall be not less than 1.25 ohms. (See 4.6.4)
3.7.5 Overspeed. The starter-generator shall be capable of being driven
at a driveshaft speed of 10,000 rpm with no-load for 5 minutes without
mechanical failure or impairing of electrical performance.
3.7.6 No-load speed. When operating as a starter at no-load and with
23 volts applied to the appropriate terminals, the starter-generator shall
develop a minimum driveshaft speed of 2,500 rpm.
3.7.7 Radial vibration. The radial vibrations shall not exceed 0.001 inch
total deflection at maximum rated speed when operated as a starter.
3.7.8 Paralleling voltage drop. Under conditions of 200 amp, 30V dc,
8,000 rpm with starter-generator stabilized in temperature and an air inlet
temperature of 25°C, the voltage drop between terminals D and E shall be set at
2V - 5 per cent. The generator equalizing voltage shall be obtained between
terminal E and the negative brushes or a tap in the winding between negative
brushes and terminal E. (See 4.6.8)
3.7.9 Dielectric strength. The starter-generator shall withstand a test
voltage of 500V for 1 minute, or 600v for 1 second, at commercial frequency
applied between windings and between each winding and frame.
3.7.10 Ripple voltage-generator. The starter generator ripple voltage,
when instrumented as shown on Figure 4 and operated at speeds of 3,800, 6,000
and 8,100 rpm under no-load, half-load, and rated-load, shall not exceed 1.5V.
3.7.11 Cranking torque and speed. The starter-generator, when connected
and operated as a starter, shall be capable of delivering the minimum cranking
torque and speed requirements specified on Figures 1 and 2, with an external
resistance of 1.25 ohms corrected in the shunt field circuit.