ABAC AS-7.5251BM 7.5 HP Rotary Screw Air Compressor - Base Mount, 125 PSI, 30.5 CFM, 67 dBA

The ABAC AS-7.5251BM is the 7.5 HP base mount machine in the AS-B screw range, a rotary screw air compressor that delivers 30.5 CFM at 125 PSI and runs at 67 dBA, quiet enough to sit in the work area instead of a separate compressor room. Base mount means it ships without a tank, so it plumbs into a receiver you already own or one sized to the job. Choose 230V single-phase (AS-7.5251BM) or 208-230-460V three-phase (AS-7.5253BM); both are the same machine in the same 32 by 24 inch cabinet.

Key specifications

• Models: AS-7.5251BM (230V single-phase) and AS-7.5253BM (208-230-460V three-phase)
• Motor: 7.5 HP
• Air delivery: 30.5 CFM
• Working pressure: 125 PSI
• Noise level: 67 dBA
• Mounting: base mount, no tank
• Weight: 360 lbs
• Dimensions (L x W x H): 32 x 24 x 40 in
• Fully integrated aluminum block air end
• Vertical oil separation technology
• Digital controller with menu driven operation and programmed maintenance
• Brand: ABAC, part of the Atlas Copco group

Why a screw instead of a piston

A piston compressor builds air in bursts and needs time to cool between them. A rotary screw runs, which is why shops that use air most of the day move to one. There is no duty cycle to watch, line pressure stays flat through a shift instead of sagging and recovering, and at 67 dBA the noise sits well below a comparable reciprocating machine. The trade is that a screw dislikes short cycling, so it wants a receiver sized to its output and a demand pattern that keeps it loaded rather than starting and stopping all day.

How it compares

Across the AS-B range the air end scales with the motor on the same footprint. The 5 HP base mount gives 20.3 CFM at 335 lbs, this 7.5 HP gives 30.5 CFM at 360 lbs, and the 10 HP base mount gives 36.4 CFM at 419 lbs, all three in the same 32 by 24 by 40 inch cabinet, so stepping up buys flow rather than floor space. The 10 HP is three-phase only. If line pressure matters more than volume, the 150 PSI build of this same machine trades down to 27.1 CFM for the higher setting. If you do not already own a receiver, the same 7.5 HP air end comes tank mounted on a 71 gallon or 131 gallon tank, and with an integrated dryer on the 71 gallon and 131 gallon builds.

Typical applications

Automotive service and tire bays, small production and fabrication floors, cabinet and woodworking shops, plasma and laser tables, packaging lines, and any operation where a piston compressor is cycling too hard to keep up. The base mount build is also the one to buy when you are replacing the compressor on an existing system and keeping the receiver and piping already in place.

Setting it up

Give the cabinet clear air on the cooling side and keep it out of a hot corner, run it on its own circuit sized to the motor nameplate, and size the receiver to the demand rather than to the pipe. Oil, oil filter and separator element are the service items, and the digital controller tracks the intervals for you. Compressed air leaving any screw carries moisture, so if the air goes to paint, tires, pneumatic controls or anything that hates water, put a refrigerated dryer behind it; the ABAC COOL dryers run on standard shop power and are rated to 232 PSI. Call us with your own flow and duty cycle and we will size the dryer against this machine before you pipe it in.

Part of the ABAC AS-B 5 to 20 HP screw range from the Atlas Copco group. See the full rotary screw air compressor lineup, the fixed speed screw compressors, and our air dryers.

CFM measured per ISO 1217 Annex C, quoted at 109 PSI for 125 PSI maximum units. Noise measured per ISO 2151:2004 using ISO 9614/2 (sound intensity method).