Atlas Copco ZT 45 VSD (FF VSD⁺) Oil-free Tooth Air Compressor

The Atlas Copco ZT 45 VSD is the 45 kW (60 hp) air-cooled member of the ZT 15-55 VSD oil-free tooth line, and it is published with two variable-speed tiers on one frame. The first tier of the ZT 45 VSD, the ZT45VSD, is a single 8.6 bar(e) class driven by one 45 kW motor and listed at 78.5 dB(A). The second tier of the ZT 45 VSD, the ZT45VSD+, keeps the same motor but adds a 10 bar(e) class and drops the work-station noise to 68 dB(A) in a lighter 1373 kg pack. For a plant already committed to air cooling, this two-tier layout means the ZT 45 VSD can be quoted on the same footprint as a one-class workhorse or as a two-class machine that also covers a higher-pressure loop.

The ZT45VSD Tier — One 8.6 bar(e) Class

The standard variable-speed tier is printed as three measured rows at one pressure class. At Minimum the ZT45VSD opens at 4 bar(e) with 42.4–119.8 l/s, and at the Effective point of 7 bar(e) it reads 41.3–118.4 l/s; the Maximum row at 8.6 bar(e) closes at 41.1–112.7 l/s. The m³/min column runs 2.5–7.2 at Minimum and narrows to 2.5–6.8 at Maximum, so the low-speed floor barely moves while the top edge gives up flow for pressure. The data sheet lists a standard model weight of 1481 kg and an integrated MD dryer, the IMD option, on this tier.

The ZT45VSD+ Tier — Two Pressure Classes

The ZT45VSD+ shares the 45 kW motor but spreads its flow across two classes; the ZT 45 VSD range uses this tier when a second pressure band is needed. On the 8.6 bar(e) class the Minimum row starts at 4 bar(e), or 58 psig, with 40.4–135.8 l/s and the Effective row at 7 bar(e) reads 39.3–132.3 l/s; the Maximum row at rated pressure closes at 37.9–118.2 l/s. The m³/min band reaches 2.4–8.1 at Minimum and the sound pressure level for this tier is listed at 68 dB(A), ten decibels below the standard tier.

8.6 bar(e) Class of the ZT45VSD+

Read the 8.6 bar(e) class from the top of each row: the upper flow edge drops only from 135.8 to 118.2 l/s across the whole pressure travel, a band of 17.6 l/s, while the m³/min column narrows from 2.4–8.1 to 2.2–7.09. A header regulated near 7 bar(e) is sized against the Effective row at 132.3 l/s, and a line working close to rated pressure reads the Maximum row, where the lower edge still holds 37.9 l/s. The ZT 45 VSD+ therefore trades a little top-end flow for a much lower acoustic footprint than the ZT45VSD tier.

10 bar(e) Class of the ZT45VSD+

The higher class gives the ZT 45 VSD its second pressure band, and it opens at the same Minimum row because the drive shares one flow envelope. At Minimum the 10 bar(e) class reads 40.4–135.8 l/s and the Effective row at 9 bar(e) reads 37.7–112.5 l/s; the Maximum row at 10 bar(e), or 145 psig, closes at 36.9–96.9 l/s. Here the m³/min band narrows from 2.4–8.1 to 2.2–5.8, the trade a plant accepts for the extra pressure headroom on the same 45 kW motor.

Weights, Dimensions and Dryer Builds of the ZT 45 VSD

The ZT 45 VSD standard tier lists 1481 kg and the ZT 30-55 VSD frame of 2440 × 1016 × 1880 mm. The ZT 45 VSD+ tier sits on the ZR/ZT 30-50 VSD+ frame: 2005 × 1022 × 1909 mm as a pack and 2440 × 1022 × 1909 mm as a Full Feature build. The data sheet prints the VSD+ weights as three builds — pack 1373 kg, Full Feature with iMD 1646 kg and Full Feature with iD 1531 kg — and notes that the integrated dryer adds to the standard figure when it is ordered.

Sizing an Air-Cooled 45 kW Installation

Air cooling puts the placement decision first: the ZT 45 VSD rejects its heat into the room, so it fits plants with no water loop, and the 1016–1022 mm frame width lets it replace a smaller ZT 15-55 VSD unit without rebuilding the bay. The 78.5 dB(A) on the standard tier and 68 dB(A) on the VSD+ tier are A-weighted sound pressure levels at the work station, measured per ISO 2151:2004 with the KpAd correction of the test code. A plant comparing the two tiers should size against the Effective row of the pressure class it will actually regulate near, because the drive cannot exceed the printed band.

Questions Buyers Ask About the ZT 45 VSD

Which tier should I quote? Size the header first. The ZT 45 VSD standard tier holds 118.4 l/s at its Effective point on one 8.6 bar(e) class, while the ZT45VSD+ adds a 10 bar(e) class and reaches 135.8 l/s at Minimum, so a line regulated near rated pressure on the higher class keeps more flow. Both tiers share the same 45 kW motor, so the choice is set by working pressure and by the acoustic target, not by the frame.

What does the ZT45VSD+ add over the standard VSD? The ZT 45 VSD+ adds a full 10 bar(e) class, drops the work-station noise from 78.5 to 68 dB(A), and sits in a 1373 kg pack instead of 1481 kg, while keeping the same Free Air Delivery envelope at Minimum. The trade is a second pressure band the single-class ZT45VSD does not offer.

How loud is the difference between 78.5 and 68 dB(A)? Both values are sound pressure levels at the work station with the KpAd correction, not sound power figures, and the ten-decibel gap between the two ZT 45 VSD tiers is the difference between a unit that needs distance from operators and one that sits beside a line. The ZT 45 VSD range prints both footprints so a plant can place the ZT 45 VSD against its own bay rules.

From the ZT 45 VSD to the ZT 50 VSD+

When demand outgrows the 135.8 l/s top edge of the ZT 45 VSD+ 8.6 bar(e) class, the next step in the oil-free line is the Atlas Copco ZT 50 VSD⁺, whose 8.6 bar(e) class spans 40.4–153.7 l/s at its Minimum point on a 50 kW motor. Sending the measured demand profile of your header with the enquiry lets the quotation land on the model and tier that actually matches the plant.