MIL-HDBK-1004/5
4.4
Motor-Starting Effects. A series of runs was made to investigate
the maximum load allowed on the feeder when the induction motor was started.
The characteristic of the induction motor is 250-ampere inrush at 0.26-power-
factor when starting. The time to start was a little over 100 milliseconds.
Each series of runs has the steady state initial conditions as shown
on Figures A-35 through A-38. In each case, the step load is the induction
motor starting at bus 7.
4.5
Results. These figures indicate that the maximum loads on the
system are limited by the steady state voltage requirements. The figures
indicate no transient voltage problems exist, but that the steady state
voltages at the aircraft connector are well below the 113-volt minimum
requirements.
Transient voltages can be coupled to other feeder cables through the
transient and subtransient reactances of the generator. This transient
voltage coupled between feeders is less than 4 percent with a 100-ampere, 0.8-
power-factor load and is linear for larger loads. Therefore, the coupling
between the feeder circuits should not have any adverse effects on the loads
of other feeders on the system.
When the voltage is regulated at the high side of the frequency
conversion assembly transformer (4,160 volts), the voltage should remain
constant in the steady state condition. Only transient voltages will couple
to other feeder cable circuits.
A-27
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