Question 41Refrigeration & AC - Assistant Engineer

The correct answer is D) closed until the motor is connected across the line at full voltage and current drawn is below full load current. To prevent motor overload during start-up of a hermetically sealed centrifugal refrigeration system, the compressor suction gas variable inlet guide vanes should be closed until the motor is connected across the line at full voltage and the current drawn is below the full load current. This is because closing the inlet guide vanes restricts the flow of suction gas to the compressor, reducing the initial starting torque and current draw, which helps prevent motor overload. The other options are incorrect because A) and C) suggest keeping the inlet guide vanes open until the current reaches full load, which would not effectively limit the initial starting current and could lead to motor overload. Option B) is also incorrect as it does not specify that the inlet guide vanes should be closed until the current is below full load.