VFD Compressor Minimum Speeds

Email from Clay Brown on 1/2/20

See the below table for minimum speed setting for the ZPV variable speed compressors. These minimums are expressed as a percentage of the design RPM used for the vbalance selection. These minimum speeds have been selected to maintain a minimum velocity in the suction lines for better oil return.

We need to make sure that we are setting the minimum speed for ALL ZPV compressors per the table below. The ZPV066 and ZPV096 have a different minimum at 3600 RPM because we are using a smaller suction line size on these models. We also need to make sure that these minimums are properly communicated to the ATC for controls by others projects.

 

		MINIMUM SPEED (%)
DESIGN RPM		ZPV063	ZPV066	ZPV096
	3600	68	50	50
	4200	58	58	58
	4800	50	50	50
	5400	45	45	45
	6000	40	40	40
	6600	38	38	38
	7200	35	35	35