Atlas Copco ZR 75 VSD (VSD⁺ FF) Oil-free Air Compressor

Three tables carry the Atlas Copco ZR 75 VSD, and the same 75 kW (100 hp) motor sits behind all of them. Read their upper ends in order and the shape of the range becomes plain: 259 l/s at the shared Minimum row of the single-inverter machine, 242.5 l/s at the ZR 75 VSD⁺ Pack Minimum, and 185.6 l/s at the ZR 75 VSD⁺ 13 bar(e) Minimum. That last figure is not a value calculated down from the other two; it is printed on measured rows of its own.

Heat from compression leaves through the site’s water circuit, so a tower, a closed loop, or a heat recovery exchanger belongs in the utility scope at layout stage rather than becoming a ventilation problem in the production hall.

How the ZR 75 VSD Pressure Classes Diverge Above the Minimum Row

At 8.6 and 10.4 bar(e) the single-inverter ZR 75 VSD is tabulated at Minimum, Effective, and Maximum, with the working pressure printed beside each point. A 75 kW (100 hp) motor and two weight columns — Standard and FF — run unchanged through all six rows, so the class changes the flow envelope and nothing else on the canopy.

Both classes begin at 76–259 l/s; 161–548 cfm belongs to the 8.6 bar(e) row and 161–549 cfm to the 10.4 bar(e) row. The parting comes at Effective: 75–222 l/s at 7 bar(e) against 74–196 l/s at 9 bar(e). By Maximum the higher-pressure row has narrowed to 96–178 l/s, while the 8.6 bar(e) machine still holds 74–201 l/s. A header working near 7 bar(e) therefore gains nothing by specifying the higher class, and a line held above 9 bar(e) accepts 23 l/s less at the top. The identical 1925 kg Standard and 2170 kg FF figures confirm that the ZR 75 VSD delivers the same frame whichever class is chosen.

Pack, iMD, and iMDG: Three Builds, One 10.4 bar(e) Class

The ZR 75 VSD⁺ splits its 10.4 bar(e) / 150 psig data into three builds, each with four points: Minimum, Effective at 7 bar(e) / 101 psig, a 9 bar(e) / 130 psig point, and Maximum. Two NEOS inverters drive the two stages. Decimal precision differs between the Pack rows and the FF rows; the table below keeps every number in the form it is printed, without rounding one build to match another.

Across the four points, iMD and iMDG repeat 79–243, 79–230, 79–204, and 78–185 l/s, while the ZR 75 VSD⁺ Pack prints 78.2–242.5, 78.8–230, 78.6–203.8, and 77.6–184.9 l/s. The gap is a matter of formatting and of where the dryer sits, not a second motor: all three builds keep 75 kW (100 hp). Both FF builds state their Minimum at 6 bar(e) / 58 psig, against 4 bar(e) / 58 psig for the Pack, and that shift is what a low-pressure interlock has to be set against. Choosing a ZR 75 VSD⁺ build is therefore a layout and air-treatment decision made after the flow rows have been checked.

The ZR 75 VSD⁺ Measured at 13 bar(e)

The third table raises the working pressure to 13 bar(e) / 189 psig and gives three points of its own: 9 bar(e) / 131 psig at Minimum, 10.4 bar(e) / 150 psig at Effective, and 13 bar(e) / 189 psig at Maximum. It carries a 75 kW (100 hp) motor and states 67 dB(A) at the work station; those values are printed with this table, not borrowed from the 10.4 bar(e) one.

Reading the Maximum row against the 10.4 bar(e) Pack shows the trade plainly: 75.6–148.6 l/s here, 77.6–184.9 l/s there. The high-pressure ZR 75 VSD⁺ also lifts its Minimum floor to 9 bar(e), so the band both narrows and moves up. A single station that needs 13 bar(e) can be fed from this variant without a dedicated compressor standing by for that island, provided the rest of the plant does not need the wider 10.4 bar(e) envelope at the same time.

Water-Side Installation and Frame Data

Heat from both compression stages is carried away by water, so the utility scope includes a tower, a closed loop, or a heat recovery exchanger, plus service clearance at the connections. The NEOS inverter is arranged inside the cubicle. Sound figures are work-station values: 74 dB(A) on the single-inverter ZR 75 VSD table, 66 dB(A) on the ZR 75 VSD⁺ table, and 67 dB(A) on the 13 bar(e) table. Where an operator position sits close to the canopy, those three numbers are checked before the ducting and water pipes are fixed.

Frame dimensions and weights

The single-inverter ZR 75 VSD Standard frame is 1925 kg and the FF frame 2170 kg, both listed at 2180 × 1450 × 2184 mm. On the ZR 75 VSD⁺ the Pack is 2500 kg at 2030 × 1660 × 2000 mm and the FF (iMDG) build 3700 kg at 3430 × 1660 × 2000 mm; the iMD column in the weight summary prints a dash, so no value is assumed for it. A 1200 kg spread between the lightest and heaviest frames makes the delivered build the one that has to fit the bay, the floor loading, and the door, and the water connections need room on whichever side is chosen.

Duties Where the ZR 75 VSD Is Selected

Sites that already run chilled water put the ZR 75 VSD in a compact utility room and keep the production area clear of a large cooling-air duct. Oil-free air is the other condition: glass container forming, textile spinning, instrument air headers, and paint spray booths all put the compressed stream close to the product or the finish. The 8.6 bar(e) class fits a header held near 7 bar(e); the 10.4 bar(e) class covers lines with headroom above 9 bar(e); the 13 bar(e) ZR 75 VSD⁺ serves an island that cannot be stepped down. Where treated air must leave one canopy, an iMD or iMDG build takes the separate dryer tower out of the layout.

Questions Buyers Raise on the ZR 75 VSD

How much flow is given up for 13 bar(e)? The 13 bar(e) Maximum prints 75.6–148.6 l/s against 77.6–184.9 l/s for the 10.4 bar(e) Pack, a 36.3 l/s reduction at the upper end. Its Minimum also starts at 9 bar(e) instead of 4 bar(e).

Why do the iMD and iMDG rows show identical bands? Both FF builds print 79–243, 79–230, 79–204, and 78–185 l/s. The difference is in the frame: the FF (iMDG) build is listed at 3700 kg, while the iMD column prints a dash in the weight summary.

Which Minimum pressure applies to a ZR 75 VSD⁺ with the dryer inside? 6 bar(e) / 58 psig for the iMD and iMDG builds, against 4 bar(e) / 58 psig for the Pack. That is the point a low-pressure interlock is set against.

Does choosing 10.4 bar(e) change the single-inverter frame? No. The ZR 75 VSD keeps 1925 kg Standard and 2170 kg FF weights and the 75 kW (100 hp) motor in both classes; only the flow rows move.

Sizing Up to the ZR 90 VSD

Once the 96–178 l/s Maximum row at 10.4 bar(e) no longer covers the measured demand, the next size is the Atlas Copco ZR 90 VSD, rated at 90 kW (120 hp) with its own 8.6 and 10.4 bar(e) tables, a VSD⁺ branch, and a 13 bar(e) variant. Reading the ZR 75 VSD rows against the actual header first avoids specifying capacity a plant never uses near 7 bar(e); where the extra flow is real, the ZR 90 VSD keeps water cooling and the same build choices.

To settle the branch, send the model currently on your floor and the working pressure the process holds; we will match those figures to the 8.6 bar(e), 10.4 bar(e), dual-inverter, or 13 bar(e) rows and then quote the ZR 75 VSD configuration. Frame weight, sound level, and air treatment are all confirmed at that point, before an order is placed.