Atlas Copco GA 90 VSD (FF VSD⁺) Oil-injected Air Compressor

The Atlas Copco GA 90 VSD is the variable speed oil-injected screw compressor family of the GA 37-90 VSD series, rated at 90 kW of installed motor power. One family, two branches: the GA 90 VSD itself and the GA 90 VSD+ build, each offered as a Pack or a Full Feature unit. The integrated drive adjusts motor speed to the air demand of the plant, so the machine draws only the power needed for the flow actually consumed. Because the drive output is independent of supply frequency, the published performance holds for 50 Hz and 60 Hz plants alike.

Four factory pressure variants cover 4 bar, 7 bar, 10 bar, and 13 bar, and maximum working pressure for VSD machines is 13 bar(e) (188 psig). That wide band lets one machine serve low-pressure blowing and high-pressure tooling without compromise.

Technical Specifications

Performance is measured according to ISO 1217, Annex E, Edition 4:2009, and applies to both 50 Hz and 60 Hz installations.

Installed motor power equals 125 hp on every variant. The Pack weighs 1534 kg (3382 lb) and the Full Feature build 1654 kg (3646 lb). The GA 90 VSD shares the 2248 × 1080 × 1955 mm frame of its fixed speed sibling, so swapping between the two technologies changes nothing on the floor.

One Performance Table for 50 Hz and 60 Hz

Conventional compressors are built around a supply frequency, but the GA 90 VSD decouples element speed from the grid. The drive generates its own motor frequency, so the published capacities hold for 50 Hz and 60 Hz supplies with no derating. Plants that operate on either standard can therefore quote, install, and service one model without regional variants.

This also simplifies spare part planning for groups that run factories on different continents. The same element, the same drive platform, and the same service kit apply wherever the machine is installed.

The GA 90 VSD+ Branch

The family extends into the GA 90 VSD+ branch, also rated at 90 kW (125 hp) with a maximum working pressure of 13 bar(e) (188 psig). Four pressure variants cover 4, 7, 9.5, and 12.5 bar, and the mean noise level reads 74 dB(A) measured at one meter at maximum working pressure.

Capacity follows ISO 1217, Annex E, with noise determined per ISO 2151 and ISO 9614-2. The Pack weighs 1213 kg and the Full Feature build 1503 kg. The integrated dryer of the Full Feature build holds a pressure dewpoint of 3°C (37°F) at 20°C (68°F) intake conditions.

The Pack of the GA 90 VSD+ measures 1400 mm deep, 1300 mm wide, and 1968 mm high. With Full Feature the depth grows to 2178 mm while width and height stay unchanged, so the dryer module rides on the same footprint.

Flow Envelope and Pressure Stability

On the 10 bar variant the GA 90 VSD modulates anywhere from 48.3 l/s up to 257 l/s (102 to 545 cfm) as demand requires. That turn-down ratio matters because a compressor limited to a narrow speed band must unload and vent power at low demand. The GA 90 VSD simply slows down, cutting energy draw instead of wasting it.

Net pressure stays within a 0.10 bar band across the whole operating range. Sensitive downstream equipment sees a steady supply without the fluctuations that force plants to run a wide pressure band as a safety margin. Fewer starts and stops also lower stress on the element and the supply network alike.

Drive, Converter, and Control

The heart of the GA 90 VSD is the integrated variable speed drive with its own cooling loop. The drive brings the motor up without current peaks on the supply, which spares the electrical infrastructure and allows restart into a pressurized network. Every GA VSD machine is EMC tested and certified, keeping electromagnetic emissions inside industrial limits.

The Elektronikon controller manages both the compressor and the converter. It holds every operating point of the machine inside safe parameters, schedules service by actual running hours, and logs alarms in plain language for the crew.

Air Path and Full Feature Build

Compression takes place in a state-of-the-art screw element fed through a heavy duty intake filter that captures 99.9% of particles down to 3 microns. A 3-step separation process holds residual oil content below 3 ppm. An integrated water separator with electronic drain removes 100% of the condensate from the circuit.

Full Feature builds add an integrated refrigerant dryer with all wiring and piping assembled in the factory. The dryer module, filters, and drains arrive tested as one unit, so commissioning needs no field plumbing between the compressor and the treatment equipment.

Energy Recovery and Service Layout

An integrated recovery system on the GA 90 VSD can return up to 94% of the shaft power as useful heat. The output is hot air or hot water ready for space heating, wash stations, or process duties. That recovered energy serves the whole site rather than the compressor room alone.

Service points sit behind large canopy panels with access from one side. The drive, oil filter, separator, and coolers are reached from standing height, and the controller names each service item at its due date.

Where the GA 90 VSD Fits

Plants with two-shift patterns, batch production, or steadily growing air demand gain the most, since its savings grow with every kilowatt of unloaded time it removes. It also consolidates mixed-pressure sites that would otherwise run separate low and high pressure units. For fixed speed duties in the same frame, the Atlas Copco GA 250 Oil-injected Air Compressor range and the GA 90 fixed speed model complete the lineup.

GA 90 VSD FAQ

Why does the GA 90 VSD have one table for 50 Hz and 60 Hz?

The integrated drive generates its own motor frequency, so element speed does not follow the grid. Atlas Copco therefore publishes identical performance for both supplies, measured per ISO 1217 Annex E.

How much can flow turn down?

On the 10 bar variant output modulates from 48.3 to 257 l/s (102 to 545 cfm). The 4 bar variant spans 37.0 to 293 l/s (78 to 621 cfm), the widest envelope of the family.

What pressure versions are available?

The GA 90 VSD comes in 4, 7, 10, and 13 bar with maximum working pressure of 13 bar(e) (188 psig). The GA 90 VSD+ branch covers 4, 7, 9.5, and 12.5 bar at the same 90 kW (125 hp) motor rating.

What is the difference between the GA 90 VSD and the GA 90 VSD+?

Both branches run the same 90 kW (125 hp) motor and the same 13 bar(e) maximum. The GA 90 VSD covers 4 to 13 bar at 73/74 dB(A) on a 2248 × 1080 × 1955 mm frame, while the GA 90 VSD+ covers 4 to 12.5 bar at 74 dB(A) in a more compact package that weighs 1213 kg as a Pack.

How heavy is the GA 90 VSD?

The GA 90 VSD Pack weighs 1534 kg and the Full Feature build 1654 kg. The GA 90 VSD+ weighs 1213 kg as a Pack and 1503 kg with Full Feature.

Which plants benefit most from the GA 90 VSD?

Sites whose air demand swings between shifts or seasons gain the most, because the drive removes unloaded running. It also consolidates mixed-pressure plants that would otherwise run separate compressors for each pressure level.