ABAC AS-20S503BM 20 HP Rotary Screw Air Compressor - Base Mount, 150 PSI, 78 CFM, 67 dBA

The ABAC AS-20S503BM is a 20 HP rotary screw air compressor for shops that need a high volume of air at 150 PSI, quietly, across a full shift. It delivers 78 CFM at 150 PSI and runs at 67 dBA. This is the base mount version, so it ships without a tank and plumbs into an air receiver you already own or one sized to your demand. Power is 208-230-460V three-phase.

Key specifications

• Model: AS-20S503BM (part number 4152028456)
• Motor: 20 HP, energy efficient
• Air delivery: 78 CFM
• Working pressure: 150 PSI
• Noise level: 67 dBA
• Mounting: base mount, no tank
• Power supply: 208-230-460/3/60
• Weight: 690 lbs
• Dimensions (L x W x H): 44 x 31 x 49 in
• Fully integrated aluminum block air end
• Eco friendly vertical oil separation
• Duty: continuous

Typical applications

Production and fabrication floors, automotive and fleet service bays, tire and truck shops, cabinet and woodworking shops, and any operation running air tools that call for a 150 PSI supply rather than the usual 125. ABAC positions the AS-B 20S to 30 HP range at demanding automotive and industrial work that needs a reliable and continuous supply, and that is the right way to read this machine: a rotary screw is built for continuous duty, so it holds a steady line pressure through a full shift instead of recovering between jobs.

How it compares

The S in AS-20S is the difference worth understanding: against the standard AS-20503BM at the same 20 HP and the same 150 PSI, this machine delivers 78 CFM instead of 54 CFM and runs at 67 dBA instead of 71 dBA. That is roughly 24 CFM more air from the same motor rating, which is what shops reach for when sandblasting, plasma cutting, or several bays running at once are pulling a standard 20 HP unit down. If your tools run fine at 125 PSI and you want maximum volume instead, the AS-20S253BM gives you 81.9 CFM from the same 690 lb, 44 x 31 x 49 in package.

Stepping up the range costs nothing in floor space, because the 25 and 30 HP base mount machines use the same 44 x 31 x 49 in cabinet. At 150 PSI the AS-25503BM carries 92.2 CFM at 69 dBA and 723 lbs, and the AS-30503BM carries 103.1 CFM at 70 dBA and 759 lbs. Each step up the range is also a step up in noise, so if the compressor shares a room with people, the 67 dBA of the AS-20S is worth protecting.

Installation notes

Because this is a base mount machine, settle the receiver before it arrives. The tank has to suit the duty cycle and the size of the largest single air draw on the system, and an undersized one will make a 20 HP screw cycle more than it should. ABAC's own tank mount build of this compressor, the AS-20S503TMD, pairs it with a 132 gallon receiver, which is a sound starting point when sizing a tank for 78 CFM. At 44 x 31 x 49 in and 690 lbs this is a set in place unit, so check the door width and the floor route in advance.

Run it on a dedicated three-phase circuit sized to the motor nameplate, and leave clear space on the cooling air side so the package is not recirculating its own hot air. Oil, oil filter, air filter and separator element are the scheduled service items on a screw package, and keeping a spare set on the shelf stops a routine service from turning into downtime.

Sizing the rest of the system

Base mount is the starting point for a modular compressed air system: pair it with a receiver sized to your demand, then add a dryer downstream if your air tools or finishing work need moisture control. If you would rather buy the moisture control already matched, mounted and wired, the AS-20S503BMD adds an integrated refrigerated dryer on the same base at 798 lbs, and the AS-20S503TMD arrives as a complete station on a 132 gallon receiver. Buying the dryer separately instead? Size it above 78 CFM from our refrigerated air dryers, and see our vertical air receiver tanks and horizontal air receiver tanks for the receiver itself.

Part of the ABAC AS-B screw range from the Atlas Copco group, built around a fully integrated aluminum block, eco friendly vertical oil separation and an energy efficient motor, with an air end designed to limit air loss, noise and vibration. Browse the rest of our rotary screw air compressors and our fixed speed rotary screw air compressors.