Description
The Atlas Copco GA 18 VSD is the entry machine of the GA 18-37 VSD+ group and carries variable speed drive into the 18 kW class of the oil-injected screw range. An oil-cooled interior permanent magnet motor rated at 18 kW drives the compression element through direct drive, and the inverter inside the VSD+ cubicle adjusts its speed continuously so the delivered air follows the demand of the plant.
Three pressure settings from 4 to 9.5 bar(e) cover the common industrial networks, and the flow window reaches from 15.0 to 63.2 l/s between the lowest and the highest setting.
For plants that run a heavy morning shift and a lighter afternoon program, the value of the machine shows on the electricity meter. When production pauses, the drive slows the GA 18 VSD toward the bottom of its flow window instead of running unloaded at full speed, and the savings of up to 50 percent come from the hours that used to be wasted between load phases.
The upright package stands 1590 mm high, weighs 367 kg as a standard unit and posts 67 dB(A), so the machine replaces a fixed-speed unit of the same rating without any change to the room.
Where the GA 18 VSD Fits in the Oil-Injected Range
Atlas Copco positions the GA 18 VSD at the base of the GA 18-37 VSD+ group, directly above the compact GA 7-15 VSD+ group that tops out with the GA 15 VSD. Workshops that outgrow the 15 kW class move up to this rating and keep the same control concept, the same direct drive and the same service logic.
Above it, the GA 22 VSD shares the identical platform with a wider flow window, so a plant can standardize on one machine family across the whole 18 to 37 kW band.
What the VSD and FF Names Cover
The GA 18 VSD is the standard build. It delivers compressed air for networks with external treatment and carries the full drive train of the platform. The GA 18 VSD FF adds the refrigerant dryer to the same frame, so dry air leaves the machine directly and no separate dryer has to be purchased, installed or piped. Both builds share the drive technology and the sound level of the group, and the FF version remains a single upright package that reaches 1590 mm high.
The Upright Package
The vertical layout of the GA 18-37 VSD+ group keeps the separator vessel, the element and the motor stacked in one column, which cuts the footprint of the machine room. A workshop that needs dry air from a plug-and-play station picks the Full Feature unit. A plant with its own treatment room picks the standard build and pipes the wet air to it, and both versions fit through the same doorway.
Technical Specifications of the GA 18 VSD
Unit performance of the GA 18 VSD is measured according to ISO 1217 edition 4, annex E, and the mean noise level follows ISO 2151 with a tolerance of 3 dB(A). The FAD figures of the group are referenced at an effective working pressure of 4 bar(e), and the maximum working pressure of the platform is 13 bar(e). The table lists the standard build and the Full Feature build side by side.
| Model | Motor rating | Noise | Weight |
|---|---|---|---|
| GA 18 VSD | 18 kW / 25 hp | 67 dB(A) | 367 kg |
| GA 18 VSD FF | 18 kW / 25 hp | 67 dB(A) | 480 kg |
FAD Across the Three Pressure Settings
The flow window of the GA 18 VSD opens between the lowest and the highest speed at every reference pressure. The figures below are the minimum and maximum free air delivery at each setting, and they show why the machine covers both a light night program and a full afternoon peak without unloading.
| Working pressure | FAD range (l/s) | FAD range (m³/h) | FAD range (cfm) |
|---|---|---|---|
| 4 bar(e) / 58 psig | 15.0 – 63.2 | 53.9 – 227.5 | 31.7 – 133.8 |
| 7 bar(e) / 102 psig | 14.7 – 61.8 | 53.0 – 222.6 | 31.2 – 131.0 |
| 9.5 bar(e) / 138 psig | 16.9 – 53.0 | 61.0 – 190.8 | 35.9 – 112.3 |
Dimensions and Weight
The GA 18 VSD shares the frame of the GA 18-37 VSD+ group. The standard build measures 780 mm in depth, 811 mm in width and 1590 mm in height, while the Full Feature build widens to 1273 mm to house the integrated dryer. At 367 kg the standard unit moves on a pallet truck, and the 480 kg FF package still fits the floor plan of the machine it replaces.
How the Drive Matches Air Demand
Pressure Stability Without Unloaded Running
A fixed-speed compressor reacts to falling line pressure by loading and unloading in steps, and every unloaded minute wastes power. The GA 18 VSD instead narrows the band to a tight window: the inverter raises or lowers the motor speed so the delivered flow equals the consumption at every moment. Plants that previously sized a receiver to buffer the load cycles of a fixed-speed machine can keep the vessel smaller, because the supply side itself becomes continuous.
Soft Starting Under System Pressure
The drive brings the motor up from zero speed with a controlled current, so the GA 18 VSD starts against a pressurized network without inrush peaks. This removes the need for unload start timers and lets the machine follow a production schedule that switches several times a day. The absence of peak starting currents also relieves the electrical installation of the workshop.
The iPM Motor and the VSD+ Cubicle
Oil-Cooling and Protection
The interior permanent magnet motor of the GA 18 VSD reaches the IE4 efficiency class and is cooled by the same oil that lubricates the element, which removes a separate cooling circuit and keeps the rotor at a stable temperature across the whole speed range. The motor carries the IP66 rating and needs no cooling air flow, so dust in the machine room cannot reach the windings. The VSD+ cubicle integrates the inverter and the electricals in the enclosure, so no wall-mounted cabinet has to be planned.
Sentinel Valve and Direct Drive
The Sentinel valve protects the element against back-flow at standstill and is fully maintenance free. The direct coupling between motor and element removes transmission losses, belts and a shaft seal from the service plan. Together with the oil-cooled motor this is why the GA 18 VSD keeps its output constant while the machine ages.
Full Feature: The Integrated Refrigerant Dryer
The Full Feature build of the GA 18 VSD integrates the refrigerant dryer behind the same panels. The dryer delivers a pressure dew point of 3 degrees Celsius, which covers the air quality requirements of general manufacturing and stops moisture from reaching the tools and the piping. Because the dryer is wired and plumbed at the factory, the FF package arrives as one unit: connect the intake, the outlet and the power supply, and the station is ready.
Condensate Management
The condensate that the dryer and the separator produce is led to one drain point through the electronic no-loss drain included as standard. The drain removes the condensate without wasting compressed air, and its manual bypass keeps the condensate moving even during a power failure. Plants that must treat the condensate before discharge connect an oil-water separator downstream of this single point.
Monitoring and Control
The Elektronikon graphic controller regulates the main drive motor and the fan of the GA 18 VSD, shows the operating status on a clear display and logs the service data. It supports two separate pressure bands, a week timer for any shift pattern and saver cycles that switch the fan and the dryer off in light load periods. The SMARTLINK data monitoring program is available for remote insight into the compressed air network, and the Elektronikon connectivity option integrates the machine into a central control room.
Applications of the GA 18 VSD
The GA 18 VSD serves plants whose demand profile changes during the day: CNC machining shops, packaging lines, automotive service centers and general manufacturing with mixed shifts. Because the machine keeps the pressure band tight, it also suits processes that react to pressure fluctuations. Workshops that move up from the GA 15 VSD gain a wider flow window on the same control concept, while plants that replace an 18 kW fixed-speed unit cut the unloaded hours out of their energy bill from the first month.
Service and Support Around the GA 18 VSD
The service plan of the GA 18 VSD follows the platform concept: one oil filter, one air filter and the oil change cover the routine intervals, and the direct drive removes belts and couplings from the schedule. The Elektronikon counts the loaded hours and indicates the next service in advance, so the maintenance can be planned instead of enforced by a sudden shutdown of the production line.
Seadweer supplies the original service parts for the GA 18 VSD, supports the commissioning and keeps the consumables available for plants that run the machine in continuous production.
FAQ
What does the GA 18 VSD deliver at 7 bar?
At the 7 bar(e) setting the flow window spans 14.7 to 61.8 l/s, which equals 53.0 to 222.6 m³/h or 31.2 to 131.0 cfm between the lowest and the highest speed.
Is the GA 18 VSD an oil-injected machine?
Yes. The oil film lubricates and seals the screw element, and the separator removes the oil from the delivered air. This design suits the industrial duties of the 18 kW class.
What does FF add to the GA 18 VSD?
The FF build integrates the refrigerant dryer with a 3 degrees Celsius pressure dew point inside the same upright frame, so dry air leaves the machine directly and no separate dryer has to be installed.
How loud is the GA 18 VSD?
The mean sound pressure level is 67 dB(A), measured at 1 m according to ISO 2151 with a tolerance of 3 dB(A).
Can the GA 18 VSD replace a fixed-speed compressor of the same rating?
Yes, one to one. The upright package stands 1590 mm high and weighs 367 kg as standard, so it takes the place of the old unit, and the inverter removes the unloaded running that consumed power before.
- Atlas Copco GA 18 VSD: the 18 kW / 25 hp entry machine of the GA 18-37 VSD+ group with variable speed drive
- Flow window 15.0 to 63.2 l/s across the 4 to 9.5 bar(e) settings, maximum working pressure 13 bar(e)
- Up to 50 percent energy savings compared with fixed-speed operation thanks to the IE4 iPM motor and the VSD+ cubicle
- 67 dB(A) mean sound pressure level, upright package 1590 mm high, 367 kg standard and 480 kg as FF
- Full Feature build integrates the refrigerant dryer with a 3 degrees Celsius pressure dew point
- Elektronikon graphic control, direct drive, Sentinel valve and electronic no-loss drain as standard
Johan Vermeulen –
Our metal workshop runs CNC machining in the day shift and cleaning lines in the evening, so the air demand never stays flat. Since the GA 18 VSD replaced our old fixed-speed unit, the motor speed follows the demand chart and the power bill dropped by about a third. It stands on the same spot as the old machine at 67 dB(A) and nobody needs ear protection next to it. Seadweer sized the 7 bar setting for our network and the Full Feature dryer keeps the dew point stable for the painting bench.