Atlas Copco GA 55 VSD (FF VSD⁺) Oil-injected Air Compressor

The Atlas Copco GA 55 VSD belongs to the GA 37-90 VSD series and pairs a 55 kW (75 hp) motor with an integrated variable speed drive. The family runs in two branches: the base machine and the GA 55 VSD+ build, each supplied as a Pack or a Full Feature unit. Because the converter synthesizes its own motor frequency, the published performance applies to 50 Hz and 60 Hz plants in one table, and maximum working pressure for VSD machines is 13 bar(e) (188 psig).

Factory variants span 4, 7, 10, and 13 bar on the base branch, letting one machine serve both low-pressure processes and high-pressure tools from a single network. The drive accelerates the motor without current peaks and allows a restart into a pressurized line.

Especificaciones técnicas

Performance is measured according to ISO 1217, Annex E, Edition 4:2009, and the same capacity envelope holds for both supply frequencies.

Every variant runs on the same 55 kW (75 hp) motor. The Pack weighs 1380 kg (3042 lb) and the Full Feature build 1480 kg (3263 lb). The machine shares the 2248 × 1080 × 1955 mm frame with the GA 75 VSD and GA 90 VSD above it in the series, so all three park on identical floor marks.

One Capacity Envelope for Both Frequencies

A conventional machine is tied to the grid: its element spins at the speed the supply and gearing dictate, and a 60 Hz plant needs a separately engineered version. The integrated drive removes that dependency by generating the motor frequency itself, so element speed and therefore flow follow demand instead of the grid.

Procurement feels the difference directly. A single selection table, one service concept, and one set of spare parts serve factories on different continents, and quotations no longer need a frequency-specific engineering pass.

The GA 55 VSD+ Branch

The newer GA 55 VSD+ build carries the same 55 kW (75 hp) rating with a 13 bar(e) maximum working pressure, in four variants covering 4, 7, 9.5, and 12.5 bar. Its mean noise level reads 67 dB(A), measured at one meter at maximum working pressure according to ISO 2151 and ISO 9614-2.

Capacity is referenced to ISO 1217, Annex E. The Pack measures 1100 mm deep, 1153 mm wide, and 1968 mm high; the Full Feature build keeps depth and height but widens to 1656 mm, because the dryer module rides beside the compressor on the shared frame instead of behind it. At 900 kg (1100 kg with Full Feature) the branch fits compressor rooms and mezzanines that the larger frame cannot enter.

The iPM Motor Branch

A third branch, the GA 55 VSD iPM, drives the element with an interior permanent magnet motor. Its table carries the same 50/60 Hz heading, covers 4, 7, 9.5, and 12.5 bar variants up to a 13 bar(e) maximum, and reads 70 dB(A) at one meter. The standard model weighs 845 kg on a 1610 × 990 × 1870 mm footprint.

Capacity is measured per ISO 1217, Edition 4:2009, with FAD referenced to the 4, 7, 9.5, and 12.5 bar(e) effective working pressures, and noise per ISO 2151 and ISO 9614-2 within a 3 dB(A) tolerance.

Following the Demand Curve

On the 7 bar variant the base machine modulates from 26.0 l/s up to 175 l/s (55 to 371 cfm) as the plant breathes. A fixed speed unit below its load point has to blow the surplus to atmosphere, spending power on air nobody uses; the variable speed machine simply slows the element and rides the demand curve instead.

Network pressure stays inside a narrow band across the whole operating range, so downstream equipment sees a steady supply and the safety margin that plants normally hold against fluctuations can shrink. Fewer load and unload cycles also ease wear on the element, the motor, and the switchgear.

Drive, Motor, and Control

The converter lives inside the canopy with its own cooling loop and is EMC tested to keep emissions inside industrial limits. Soft acceleration spares the electrical infrastructure, and a restart into a pressurized network needs no depressurizing procedure. The GA 55 VSD shares this drive concept with every VSD build in the series, so a crew trained on one machine can service the others without retraining.

The Elektronikon controller supervises compressor and drive together: it holds every operating point inside safe parameters, schedules service by real running hours, and reports alarms in plain language so the crew can act without decoding fault codes.

Air Path and the Full Feature Build

Intake air passes a heavy duty filter that captures 99.9% of particles down to 3 microns before reaching the element. A 3-step separation stage holds residual oil content below 3 ppm, and an integrated water separator with electronic drain clears condensate from the circuit. This path is identical across the GA 55 VSD branches, so air quality figures carry over from one build to the next.

The Full Feature build carries an integrated refrigerant dryer with all wiring and piping completed in the factory and tested as one unit before dispatch. No field plumbing between compressor and treatment equipment is needed, and the finished package matches the 1480 kg figure in the table above.

Where the GA 55 VSD Fits

Plants whose air draw moves between shifts, batches, or seasons gain the most, since every minute of avoided unloaded running shows up directly on the power bill. Mixed-pressure sites can consolidate two fixed speed units into one machine that covers blowing in the morning and tooling after lunch. For level, full-load duties the fixed speed Compresor de aire con inyección de aceite Atlas Copco GA 250 range and the GA 55 remain the natural choices.

GA 55 VSD FAQ

Why is there a single table for 50 Hz and 60 Hz?

The drive creates its own motor frequency, so element speed does not follow the grid, and one capacity envelope measured per ISO 1217, Annex E serves both supplies.

How far can output turn down?

On the 7 bar build flow modulates from 26.0 to 175 l/s (55 to 371 cfm); the 4 bar build spans 32.4 to 197 l/s (69 to 418 cfm).

What separates the base branch from the GA 55 VSD+?

Both carry 55 kW (75 hp) and a 13 bar(e) maximum. The base machine covers 4 to 13 bar at 69/72 dB(A) on the 2248 × 1080 × 1955 mm frame, while the GA 55 VSD+ covers 4 to 12.5 bar at 67 dB(A) in a 900 kg Pack that starts at 1100 mm deep.

What is the iPM branch?

An interior permanent magnet motor drives the element in this build. It covers 4 to 12.5 bar at 70 dB(A), weighs 845 kg as a standard model, and keeps the 13 bar(e) family maximum.

How heavy is the machine?

The Pack weighs 1380 kg and the Full Feature build 1480 kg; the GA 55 VSD+ branch weighs 900 kg as a Pack and 1100 kg with Full Feature.

What does the Full Feature build include?

An integrated refrigerant dryer with factory wiring and piping, filtration, and electronic condensate drains, delivered tested as one unit; on the VSD+ build the dryer widens the package from 1153 to 1656 mm instead of lengthening it.

Which plants gain the most from variable speed?

Sites with swinging demand, two-shift patterns, or mixed pressure levels, where the drive eliminates unloaded running and one machine replaces two fixed speed units.