单选题An un-loader is installed on an air compressor to （）.Abypass the high pressure stage to the low pressure stage on 100% of the air compressors in serviceBprevent excessive inter-stage pressure buildupCcontrol compressor discharge pressureDremove all but the frictional load during starting
单选题
An un-loader is installed on an air compressor to （）.
A
bypass the high pressure stage to the low pressure stage on 100% of the air compressors in service
B
prevent excessive inter-stage pressure buildup
C
control compressor discharge pressure
D
remove all but the frictional load during starting
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