ABAC AS-20S503BMD 20 HP Rotary Screw Air Compressor - Base Mount with Dryer, 150 PSI, 78 CFM, 67 dBA

The ABAC AS-20S503BMD is a 20 HP rotary screw air compressor with an integrated refrigerated dryer on a single base, so the air leaving the package is already dry and ready to pipe. It delivers 78 CFM at 150 PSI and runs at 67 dBA. This is the base mount build, so it ships without a receiver and plumbs into a tank you already own or one sized to your demand. Power is 208-230-460V three-phase.

Key specifications

• Model: AS-20S503BMD (part number 4152028462)
• Motor: 20 HP
• Air delivery: 78 CFM, free air delivery per ISO 1217 Annex C
• Working pressure: 150 PSI
• Noise level: 67 dBA, measured per ISO 2151:2004
• Integrated refrigerated air dryer, matched, mounted and wired at the factory
• Mounting: base mount, no tank
• Power supply: 208-230-460/3/60
• Weight: 798 lbs
• Dimensions: 55 x 31 x 49 in

Typical applications

Production and fabrication floors, automotive and fleet service bays, tire and truck shops, cabinet and woodworking shops, plasma cutting, pneumatic controls and air logic, and spray finishing where moisture in the line spoils tools or finish quality. A rotary screw is designed for continuous duty, so it holds steady line pressure through a full shift rather than recovering between jobs, and drying the air at the compressor keeps condensate out of the distribution piping instead of leaving it for traps and filters downstream to catch.

Installation notes

At 55 x 31 x 49 inches and 798 lbs this is a set in place machine, so check the door width and the floor route before delivery day. Run it on a dedicated three-phase circuit sized to the motor nameplate, leave clear space on the cooling air side so the package is not recirculating its own hot air, and route the dryer condensate to a drain point or an oil water separator rather than onto the shop floor. 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.

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 at once pull a standard 20 HP unit down. Within the AS-20S range the pressure choice costs a little flow: the 125 PSI AS-20S253BMD carries 81.9 CFM on the same 798 lb, 55 by 31 inch base. Dropping the dryer gives the AS-20S503BM at 690 lbs on a 44 inch base, and adding a receiver gives the AS-20S503TMD, the same compressor and dryer mounted on a 132 gallon tank at 1297 lbs.

Sizing the receiver

A base mount unit needs an air receiver to buffer demand and let the dryer work against a steady flow. An undersized tank will make a 20 HP screw cycle more than it should. ABAC's own tank mount build of this machine, the AS-20S503TMD, pairs it with a 132 gallon receiver, which is a sound starting point when sizing a tank for 78 CFM. See our vertical air receiver tanks and horizontal air receiver tanks.

Part of the ABAC AS-B screw range from the Atlas Copco group, built around a fully integrated aluminum block, vertical oil separation technology and an energy-efficient motor. See the rest of the rotary screw air compressors and our fixed speed rotary screw air compressors.