Atlas Copco ZT 90 VSD Oil-Free Rotary Screw Air Compressor

Description

The Atlas Copco ZT 90 VSD is the air-cooled, variable speed drive model at the top of the ZT 55-90 oil-free platform. It compresses air to 100 percent oil-free quality through two oil-free stages, and its Full Feature branch adds an integrated IMD adsorption dryer so the package delivers dried air from a single unit. The versions cover two pressure bands in 50 Hz and 60 Hz, and every branch carries the ISO 8573-1 Class 0 (2010) certification.

An Air-Cooled Package in the Oil-Free Z Range

The oil-free screw range below 100 kW is organized around the ZT 55-90 platform, and the ZT 90 VSD closes its top at 90 kW / 120 hp. The letter ZT marks the air-cooled package of the platform, while the ZR of the same frame is the water-cooled counterpart, and both share the two-stage oil-free element and the platform’s technical approach. Cooling happens through the ample cooler section inside the package, so the machine needs no external cooling-water circuit on site.

VSD and VSD FF: What Each Name Covers

Two names describe the branches of the ZT 90 VSD, and each adds one fact:

• VSD — variable speed drive: the drive adjusts the main motor speed to the air demand, which holds the pressure band steady and trims energy use at part load.
• VSD FF — Full Feature: the package integrates an IMD adsorption dryer, so drying happens inside the compressor rather than beside it, with no external instrument air required.

Each branch is built in two pressure versions, the ZT 90 VSD – 8.6 and the ZT 90 VSD – 10.4, and both 50 Hz and 60 Hz exist across the family.

Technical Specifications of the ZT 90 VSD

The table below condenses the ZT 90 VSD into its headline figures:

Rated Data at 50 Hz and 60 Hz

Each pressure version of the ZT 90 VSD is listed at three settings, and the FAD span inside every row covers the full VSD speed range at that setting. The figures are taken from the 50 Hz data sheets:

The 60 Hz data sheets for the ZT 90 VSD list the same working pressures, FAD spans and sound levels as the 50 Hz sheets, so the table above reads the same for both frequencies.

The 8.6 bar(e) version peaks at 293.9 l/s (622.7 cfm) on its minimum setting, and the 10.4 bar(e) version peaks at 289.5 l/s (613.4 cfm). Within one version, moving from the minimum to the maximum pressure setting costs about 39 l/s of peak flow. The installed motor power stays at 90 kW / 120 hp across all settings and both frequencies.

Dimensions and Weight

The footprint of the ZT 90 VSD depends on the branch, and the integrated dryer of the Full Feature version adds length to the package:

The Full Feature package is 685 mm longer than the Pack because the adsorption drum of the dryer rides inside the same canopy. Width and height are shared at 1,650 mm and 2,150 mm, so floor planning comes down to the length difference between the two branches.

Air-Cooled Design Details

The ZT carries the cooling duty inside the package. Cooling jackets around the compression stages hold the temperatures of both stages under control in different ambient conditions, and the ample cooler section keeps pressure drops low while holding a low air approach temperature. The result is a complete oil-free package that installs without a cooling-water circuit and runs continuously in severe ambient conditions.

Intake Filtration and Condensate Handling

Air enters through a two-stage dust removal system that captures 99.9 percent of particles at 3 micron, which protects the compression stages and keeps intake losses low. After compression, a water separator removes the condensate from the air stream, and the low moisture carry-over protects downstream equipment. The drive motor is an IP55 TEFC unit that protects against dust, chemicals and humidity, and the mechanical interlock of the inlet and blow-off valve handles load and unload regulation without an external air supply.

VSD Technology and Energy Efficiency

Energy dominates the cost of compressed air: over 80 percent of a compressor’s lifecycle cost is the energy it consumes, and air generation can account for more than 40 percent of a plant’s electricity bill. The ZT 90 VSD attacks that share directly. Its drive follows the air demand by adjusting the motor speed, which brings energy savings of up to 35 percent and cuts the average lifecycle cost of the compressor by 22 percent.

Pressure Stability and Turndown

The integrated design holds the net pressure band within 0.10 bar (1.5 psi), and the compressor carries no speed windows that would jeopardize the savings or the stable net pressure. Turndown is maximized to 70-75 percent, so the package keeps regulating deep into low demand instead of unloading early.

The motor is an IE3 premium efficiency unit combined with an in-house designed frequency converter, and the converter is rated for stable operation in ambient temperatures up to 50°C / 122°F. and the whole drive train is EMC tested and certified so compressor operation does not influence external sources and vice versa. Mechanical enhancements keep every component below critical vibration levels throughout the entire compressor speed range.

Air Flow Through the Package

The path of the air through the ZT 90 VSD runs in four steps, and the Full Feature branch extends the third of them into the integrated dryer:

• Filtration and first compression — the inlet filter cleans the air, the throttle valve with its integrated blow-off valve takes care of the load regulation, and the first stage raises the pressure to an intermediate level.
• Cooling and second compression — the intercooler lowers the temperature, a moisture separation system prepares the air, and the high-pressure stage brings it to the final pressure.
• Cooling and drying — the after-cooler condenses moisture out of one part of the air, while a second part flows directly into the regeneration area of the heat-of-compression MD dryer.
• Oil flow — a separate oil pump feeds cool, filtered oil to the bearings and the gears and returns it to the sump, so the oil circuit never meets the compressed air.

How the Heat-of-Compression Dryer Regenerates

In the regeneration area, the hot air from the high-pressure stage regenerates the adsorption drum and then passes through the regeneration cooler, where it is cooled down and its moisture is separated and evacuated. The cold regeneration air is mixed with the air from the after-cooler in the nozzle-ejector system, and the combined stream passes through the drying section of the adsorption drum, where the remaining moisture is removed. Dry air leaves the ZT 90 VSD FF through the outlet connection flanges, and the whole process runs on compression heat without external instrument air.

The separation between the air path and the oil path is the mechanical basis of the Class 0 certificate. The compressed air touches only oil-free surfaces from inlet to outlet, which is why the ZT 90 VSD appears in plants where a trace of oil would stop production.

Monitoring and Control

The Elektronikon MK5 Touch controller runs the ZT 90 VSD and its integrated converter from one full-color touch display. Clear icons and intuitive navigation give fast access to all of the important settings and data, the controller monitors the running conditions and the maintenance status, and the built-in remote control and notification functions come with a simple integrated webpage as standard. Support covers 31 different languages, including character-based languages.

SMARTLINK and Load Control Functions

SMARTLINK monitors the compressed air installation over the ethernet: customized reports track the energy efficiency of the compressor room, components are replaced on time to keep uptime high, and early warnings avoid breakdowns and production loss. Around that, the control algorithms trim the load profile of the ZT 90 VSD in three ways:

• Dual set-point and automatic stop — the controller switches between two setpoints manually or automatically, and the sophisticated algorithm runs the drive motor only when needed.
• Delayed Second Stop — the controller takes the running conditions into account and allows the machine to stop when no frequent motor starts preceded, which generates major savings against a fixed unload timer.
• Timer functions and dual pressure band — the machine stops when no air is needed, and lower pressure settings during nights and weekends cut the energy draw further.

Installations with three or more machines add the Optimizer 4.0 central controller. It regulates pressure, capacity and speed across the group, prevents higher pressures than required and excess unloaded running, and compensates automatically for pressure drops caused by filters, piping and dryers.

Air Quality and Applications

Atlas Copco was the first compressor manufacturer to receive the ISO 8573-1 CLASS 0 certification, with TÜV as the certifying body, and the ZT 90 VSD carries that certification on the air at the outlet flange. The certification followed type testing in which all possible oil forms were measured across a range of temperatures and pressures, and no traces of oil were found in the output air stream. For the buyer, the class removes interpretation work, because the oil limit behind Class 0 is zero.

The applications cluster where air purity decides product quality. Food and beverage plants run the ZT 90 VSD for fermentation, packaging, aeration, transportation, filling and capping, cleaning and instrument air. Textile mills use certified oil-free air for spinning, weaving, dyeing, texturizing, winding and coning, and pharmaceutical production depends on strict moisture control that clean, dry air supports.

Power plants and oil and gas installations form the second cluster. In power generation the ZT 90 VSD supplies flue gas desulphurization, oxidation air and fluidized beds around the clock, and in oil and gas fields it covers control air, instrument air and buffer air. In each case the air-cooled design removes the need for a cooling-water circuit at the installation site.

Choosing Between the 8.6 and 10.4 Versions

The ZT 90 VSD – 8.6 covers the general plant band up to 8.6 bar(e) / 125 psig and holds the highest peak flow of the family at 293.9 l/s. The ZT 90 VSD – 10.4 reaches 10.4 bar(e) / 150 psig for higher-pressure processes and still peaks at 289.5 l/s. Matching the version to the real process pressure keeps the operating point where the data sheets put it.

Service and Support Around the ZT 90 VSD

Service parts are grouped together for ease of access, which keeps service time minimal, and all components are designed for serviceability and a long-lasting lifetime. Optional service plans extend the warranty, and the silenced canopy keeps the working conditions around the package comfortable for everyone in the immediate environment. The Elektronikon records support the inspection conversation with warning indications, maintenance scheduling and online visualization of the machine’s condition.

Seadweer supplies genuine Atlas Copco spare parts and service kits for the installed base of the ZT 90 VSD and its Full Feature branches. Send us the compressor model together with the parts you need, and the correct items are confirmed with the quotation in one pass.

FAQ

What does the ZT in the ZT 90 VSD mean?

The letter marks the cooling type of the package. The ZT 90 VSD is the air-cooled oil-free compressor, and the ZR of the same platform is the water-cooled counterpart.

What does FF add to the ZT 90 VSD?

FF stands for Full Feature: the package integrates an IMD adsorption dryer that regenerates with compression heat. The branch adds 685 mm of package length and 400 kg of weight, and it needs no external instrument air.

How deep can the ZT 90 VSD turn down?

Turndown is maximized to 70-75 percent, with no speed windows in the operating range. The net pressure band stays within 0.10 bar across the whole speed range.

Does the ZT 90 VSD exist in 60 Hz?

Yes. The ZT 90 VSD is built in 50 Hz and 60 Hz, and the 60 Hz data sheets list the same working pressures, FAD spans and sound levels as the 50 Hz sheets.

How loud is the ZT 90 VSD?

The ZT 90 VSD – 8.6 is rated at 78 dB(A) at the work station, and the ZT 90 VSD – 10.4 at 77 dB(A). The silenced canopy and the integrated pulsation damper hold the sound pressure level in that band.

Which industries use the ZT 90 VSD?

Food and beverage, textiles, pharmaceuticals, power plants and oil and gas are the main users. All of them specify certified oil-free air, and many of them pick the air-cooled package where no cooling water is available.