To prevent motor overload during start-up of a hermetically sealed centrifugal refrigeration system, what is true concerning the compressor suction gas variable inlet guide vanes?

Correct Answer: Option D — closed until the motor is connected across the line at full voltage and current drawn is below full load current

Centrifugal compressor variable inlet guide vanes must be closed during start-up to minimize refrigerant mass flow, preventing electrical motor overload and high inrush current spikes.