Atlas Copco ZT 55 VSD (FF VSD⁺) Oil-Free Rotary Tooth Air Compressor

Description

The Atlas Copco ZT 55 VSD is the air-cooled member of the ZR/ZT 37-55 VSD group, rated at 55 kW / 75 hp and built on the oil-free rotary tooth element. Two pressure versions split the range: the 8.6 bar(e) build serves networks that work around 7 bar, and the 10 bar(e) build serves the plants that need the higher level at the point of use.

The integrated Variable Speed Drive regulates the motor between 30 and 100 percent of maximum capacity, so the flow follows the demand instead of cycling between load and unload. Air cooling removes the cooling water circuit from the installation, and the package holds ISO 8573-1 CLASS 0 (2010) certification verified by TÜV.

Two Pressure Versions on One Air-Cooled Frame

Atlas Copco publishes the ZT 55 VSD with two working bands, and the difference between them is more than a single set point. The 8.6 bar(e) version carries the widest flow in the group, while the 10 bar(e) version trades a part of that flow for a higher network pressure.

What the 8.6 bar(e) Version Delivers

The 8.6 bar(e) build of the ZT 55 VSD regulates across a working band from 4 to 8.6 bar(e). At the minimum point of 4 bar(e) it delivers 42.4 to 143.7 l/s, at the effective point of 7 bar(e) 41.3 to 142.5 l/s, and at the maximum point of 8.6 bar(e) 41.4 to 138.8 l/s, which equals 87.1 to 294.1 cfm.

That flow profile suits a plant whose network sits near 7 bar and whose consumption moves through the day. The drive keeps the pressure at the set point with a regulation band that stays above 41 l/s at every working point, so the machine never drops below the minimum it needs to hold the network.

What the 10 bar(e) Version Delivers

The 10 bar(e) build of the ZT 55 VSD shifts the band upward. It starts at 34.8 to 139.1 l/s at 4 bar(e), passes 33.9 to 138.8 l/s at 7 bar(e) and reaches 32.3 to 122.0 l/s at the 10 bar(e) maximum, which equals 68.4 to 258.5 cfm.

Plants with long distribution nets, high pressure drops or a process that needs 9 to 10 bar at the tool take this version. The minimum flow drops to about 32 l/s at the top of the band, so the ZT 55 VSD still turns down deeply when the shift runs light, and the motor rating stays the same 55 kW / 75 hp in both versions.

No Cooling Water to Organise

The Z letter in the name marks the air-cooled format, and that single decision changes the installation. There is no cooling water circuit to design, no water treatment to maintain and no risk of a fouled water side reducing the heat rejection over the years. The ZT 55 VSD rejects the compression heat into the room air instead.

The Three Coolers and the Fan

An electric motor driven fan moves the cooling air across three heat exchangers: the oil cooler, the intercooler and the aftercooler. The cooling system runs three parallel circuits, and the air path leaves the high pressure stage through a pulsation damper with an integrated check valve before it reaches the aftercooler.

The air-cooled design also sets the room requirements. The machine needs an adequate ventilation path so the heat leaves the building, and where that heat is captured instead of exhausted, it can be used for space heating in the cold season. Air cooling keeps the package at 70 dB(A), three decibels above the water-cooled ZR 55 VSD.

Standard and Full Feature: ID or iMD Inside the Canopy

Two builds define what leaves the frame, and the choice decides how much air treatment stays outside:

• Standard — the compressor with its coolers and the oil-free element, feeding a dryer and filters installed downstream.
• Full Feature — the same package with a dryer integrated inside the canopy, so the outlet delivers dry air directly.

The ZT 55 VSD Full Feature connects either an ID refrigerant dryer or an iMD heat of compression dryer. The ID dryer reaches a pressure dew point of 3°C / 38°F at the lowest investment, while the iMD dryer suppresses the dew point by 40°C / 72°F and reaches -20°C / -4°F at an ambient of 20°C / 68°F, using the heat of compression for regeneration with no purge air loss.

The iMD option is published for the 8.6 bar(e) version of the ZT 55 VSD, where the package weighs 1,740 kg with the adsorption dryer on board. The 10 bar(e) version lists no iMD weight, and its air treatment follows the ID route or an external dryer chosen for the duty.

Energy: How the Drive Follows the Load

Energy takes 70 percent of the lifecycle cost of a compressor over ten years, against 15 percent for investment and installation and 15 percent for maintenance. The drive of the ZT 55 VSD works on that largest share by adjusting the motor speed to the air demand, with energy savings of up to 35 percent against a fixed-speed machine.

Regulation is continuous between 30 and 100 percent of maximum capacity, and the motor can run at any speed in that band because no resonance frequency has to be avoided. There is no blow-off to the atmosphere and no unload running, so the pressure in the network stays flat while the consumption moves.

What the Controller Adds

The Elektronikon monitoring system carries three algorithms that lower the bill further. Delayed Second Stop allows the machine to stop when no frequent motor start preceded, timer functions shut the package down when the plant needs no air, and a dual pressure band lowers the network pressure at nights and weekends.

• NEOS frequency converter built in-house, in a cubicle stable up to 50°C / 122°F.
• Motors developed for VSD duty, with cooling designed around low speed operation.
• EMC tested and certified drives on every VSD compressor, so neighbouring equipment stays unaffected.
• Vibration levels held below the critical range across the whole speed band.

Technical Specifications of the ZT 55 VSD

The table below gathers the headline figures of the ZT 55 VSD:

Rated Data by Pressure Version

The 8.6 bar(e) version of the ZT 55 VSD covers three working points:

The 10 bar(e) version carries the same three points one band higher:

Free air delivery of a variable speed machine is stated at the maximum working pressure of the variant, following ISO 1217. The gap between the 8.6 and the 10 bar(e) version appears mostly at the top of the band, where the higher pressure level costs about 17 l/s of the 8.6 bar(e) flow.

Dimensions and Weight

Every build of the ZT 55 VSD shares one outline:

The package measures 2,440 mm in length, 1,026 mm in width and 1,880 mm in height whether or not a dryer sits inside it. A plant that later adds the dryer therefore keeps the same floor plan, and the air-cooled design needs no water connection to be reworked.

Class 0 Air and the IE4 Drive Train

Atlas Copco pioneered oil-free air technology for more than sixty years and was the first manufacturer awarded ISO 8573-1 CLASS 0 certification. TÜV tested the range with the most rigorous methods available, measuring every possible oil form across temperatures and pressures, and found no trace of oil in the output stream.

The Antwerp plant that builds the Z range holds ISO 22000 certification for its food safety management system, which applies to the compressors and the related dryers and filters. That combination is what places the ZT 55 VSD in food, pharmaceutical and electronics production, where particles, moisture and oil are the three contaminants under control.

Tooth Element, Motor and Gearbox

The oil-free tooth element turns without contact between the rotors, and the timing gears hold the clearance between them. A super premium efficiency IE4 motor drives the element through a gearbox design proven across the installed base, and the oil circuit serves the bearings, the gears and the element jackets without any oil reaching the air path.

Where the ZT 55 VSD Fits in a Compressor Room

The ZT 55 VSD works as the trimming machine of a mixed installation. A plant with a steady base load runs a fixed-speed compressor at its efficient point and lets the ZT 55 VSD cover the swings above it, which is the arrangement a central controller manages best.

Atlas Copco offers three levels of coordination for that room. The built-in EQ4i and EQ6i algorithms handle small groups, the Equalizer 4.0 sequencer manages a larger set, and the Optimizer 4.0 controller runs the whole installation with advanced rules. SMARTLINK adds remote monitoring and reports the energy profile of the ZT 55 VSD to a tablet or a plant network.

Where the load runs flat rather than variable, the fixed-speed ZT 55 of the ZR/ZT 55-90 platform covers the same 55 kW rating with a different philosophy: it holds 146.3 l/s at 7.5 bar(e) in a heavier frame, and it makes sense where the demand never moves. The ZT 55 VSD answers the opposite case.

Applications of the ZT 55 VSD

Plants without a cooling water supply are the natural home of the ZT 55 VSD. Packaging halls, bottling lines and assembly shops in leased buildings pick the air-cooled package because the installation ends at the power cable and the air outlet, and nothing has to be piped through the wall.

Food and beverage production uses the oil-free air for fermentation, aeration, filling and capping under the CLASS 0 certificate. Pharmaceutical plants use it from tablet coating to bottling, electronics manufacturers clear microscopic debris from chips and boards, and textile, chemical and battery plants complete the list of industries where a trace of oil is not acceptable.

Service and Parts Around the ZT 55 VSD

The ZT 55 VSD is designed for long overhaul intervals, few service interventions and minimal maintenance cost, and every machine is tested before delivery. A global service organisation with field engineers in 160 countries supports the installed base, and AIRScan audits with the AIRchitect simulation show where a running installation still loses energy.

Seadweer supplies genuine Atlas Copco parts and service kits for the ZT 55 VSD and its Full Feature variants, covering the intake and cooler components, the oil circuit parts and the dryer service items. Send us the machine model together with the parts you need, and the correct items are confirmed with the quotation in one pass.

FAQ

Is the ZT 55 VSD available in a 10 bar(e) version?

Yes. The ZT 55 VSD is published in an 8.6 bar(e) and a 10 bar(e) version, both rated at 55 kW / 75 hp. The 10 bar(e) build delivers 32.3 to 122.0 l/s at its maximum working pressure.

What is the difference between the two ZT 55 VSD versions?

The 8.6 bar(e) version reaches 42.4 to 143.7 l/s at 4 bar(e) and 41.4 to 138.8 l/s at 8.6 bar(e). The 10 bar(e) version shifts the band upward and runs 34.8 to 139.1 l/s at 4 bar(e).

Does the ZT 55 VSD need cooling water?

No. The ZT 55 VSD is air-cooled: an electric motor driven fan moves room air across the oil cooler, the intercooler and the aftercooler. The water-cooled equivalent of the same rating is the ZR 55 VSD.

How heavy is the ZT 55 VSD?

The package weighs 1,485 kg without a dryer, 1,615 kg with the ID refrigerant dryer and 1,740 kg with the iMD heat of compression dryer on the 8.6 bar(e) build. The footprint stays at 2,440 × 1,026 × 1,880 mm.

How loud is the ZT 55 VSD?

The sound pressure level reads 70 dB(A) on both pressure versions. The air-cooled design rejects the heat into the room, so the ventilation path of the compressor room has to carry that load away.

Can the ZT 55 VSD run with other compressors?

Yes. The ZT 55 VSD works as a trimming machine next to a fixed-speed base compressor, and the EQ4i and EQ6i algorithms, the Equalizer 4.0 sequencer or the Optimizer 4.0 controller coordinate the group.