"空气压缩机组" can be translated into English as "air compressor unit" or "air compressor set".
"Air compressor unit" is a common term used to describe a complete system or apparatus for compressing air, which includes the compressor itself along with any associated components or accessories.
"Air compressor set" can also be used to convey the idea of a group or assembly of air compressors or related equipment, though it may sometimes be interpreted more broadly to include a collection of items rather than a single integrated unit.
In most contexts, especially when referring to a pre-assembled or standardized piece of equipment, "air compressor unit" would be the more appropriate and commonly used term.