We have some 28.5 VDC ground power units where I work, & as well as ground power they have a soft start feature. When set to soft start the pilot initiates the starting procedure, & the output from the power unit starts at low voltage & ramps up to 28.5 volts. The idea is to reduce shock on aircraft electrical & mechanical components.
My understanding is that only some aircraft make use of this (I was told the T-33 is one of them). Does anyone know what other aircraft can make use of soft start?