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 C — 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 remain fully closed during start-up to minimize gas throughput, drastically reducing starting torque requirements and preventing electrical motor overload when connecting across the line at full voltage.