7.5kW 10HP Portable Screw Air Compressor 380V PMVF With Integrated Air Dryer: Specification, Sizing And Buyer Guide

A 7.5kW / 10HP portable screw compressor with 380V three-phase supply, permanent magnet variable frequency control, and an integrated air dryer is a compact solution for workshops, laser cutting auxiliaries, small manufacturing lines, automotive bays, pneumatic tool stations, and mobile service units. The “PMVF” configuration combines a PM motor, variable frequency drive, rotary screw airend, receiver tank, refrigerant dryer, and filtration in one package. This reduces installation time, stabilizes pressure, and delivers cleaner dry air than a bare piston or fixed-speed unit.

What PMVF Means In This Compressor Class

PMVF is commonly used for permanent magnet variable frequency screw compressors. Each part affects performance:

• Permanent magnet motor​ – high-efficiency synchronous motor, often IE4-class in premium designs, with strong low-speed torque and better partial-load efficiency than standard induction motors.

• Variable frequency control​ – the inverter adjusts motor rpm to match air demand. Instead of full-speed load/unload cycling, the airend produces only the required volume, saving energy during partial demand.

• Screw airend​ – rotary twin-rotor compression provides continuous, low-pulsation air suitable for 24-hour duty in many industrial settings.

• Integrated dryer and tank​ – all-in-one packages combine receiver, refrigerant dryer, filters, and controller. This is sometimes called 3-in-1 or 4-in-1 depending on whether tank, dryer, filter, and compressor are included.

Typical 7.5kW 10HP PMVF Performance Range

Actual free air delivery depends on airend size, pressure setting, motor efficiency, intake temperature, and whether the package is tank-mounted or direct-pipeline. Representative market ranges for 7.5kW/10HP PM VSD screw units are:

One 10HP PM VSD listing shows 1.1 m³/min at 8 bar, 0.9 at 10 bar, and 0.72 at 12 bar. Another PM model shows 1.11 at 8 bar, 0.89 at 10 bar, and 0.75 at 13 bar. A compact integrated unit may list around 1.05 m³/min at 8 bar with direct drive and air cooling.

Because pressure and volume trade off, buyers should specify the compressor by FAD at the required working pressure, not by maximum bar alone.

Integrated Air Dryer Specifications

An integrated refrigerant dryer is one of the main advantages of this package. Typical parameters in 7.5–10HP all-in-one systems include:

• Dryer type: air-cooled refrigerant dryer

• Pressure dew point: around 2–10°C, depending on ambient and load

• Dryer capacity matched to compressor FAD, often 1.5–2.0 m³/min in integrated packages to avoid bottleneck

• Combined particulate and coalescing filtration, with some packages adding fine 0.01-micron or activated-carbon stages for sensitive applications

• Automatic or timed drains on tank, dryer, and filter bowls

For most workshops, 2–10°C pressure dew point is adequate. For outdoor winter lines, pharmaceutical/electronics grades, or very low-humidity laser air, add a desiccant dryer or specify lower dew-point treatment separately.

Portable Package Layout And Tank Options

“Portable” in the 7.5kW screw class can mean different things:

• Compact skid without large tank​ – screw block, PM motor, VSD, small receiver, and dryer in one cabinet. Examples are around 820–900 mm wide/deep and 870–880 mm high for small VSD packages, weighing from about 130 kg.

• Mobile all-in-one with receiver​ – compressor, dryer, filters, and horizontal/vertical tank on wheels or fork pockets. Tanks may be 100L, 210L, 300L, or 340L depending on duty. One 7.5kW 4-in-1 model is listed near 1450×930×1300 mm, while another integrated laser package uses a 340L tank and larger frame.

• Jobsite portable electric screw​ – wheeled chassis for workshops or indoor relocation. True construction portables are often diesel and much larger, but a 10HP electric portable is best for indoor/mobile industrial use rather than rough off-road sites.

For a 1.1 m³/min screw, a 100–210L tank is enough for pressure stabilization in variable demand. A 300L+ receiver improves buffering for intermittent high-demand tools but increases footprint and weight.

Electrical Supply For 380V 7.5kW PMVF

Most 10HP PMVF units are built for 380V/50Hz three-phase, with 400V, 415V, 220V, or 480V options depending on market. For 380V three-phase, theoretical full-load current is roughly:

I ≈ 7500 ÷ (√3 × 380 × 0.85–0.90 efficiency/power-factor) ≈ 13–16A

Actual nameplate current depends on motor efficiency, PM design, and inverter losses. The VSD provides soft start and limits inrush compared with direct-on-line motors; some VFD starters keep starting current near 1.2× rated, compared with much higher DOL starting. Installation recommendations:

• Use a dedicated 3-phase breaker sized by local code and nameplate, not by motor kilowatt alone.

• Confirm cable size for run length, ambient temperature, and enclosure rating.

• Verify VFD compatibility with supply voltage tolerance, earthing, and residual-current protection.

• Keep the compressor away from welding interference, excessive dust, and poor ventilation.

• For portable units, use compliant industrial connectors, not domestic extension cords.

PMVF Vs Fixed-Speed Screw Vs Piston

A 7.5kW portable screw should be compared with the alternatives before purchase.

Screw compressors generally provide smoother air, longer continuous duty, lower noise, and fewer valve/ring issues than pistons. PMVF adds savings when demand fluctuates, because the motor slows instead of cycling at full speed.

Air Tool And Application Sizing

With about 1.1 m³/min at 8 bar, a 10HP PMVF portable covers many small-industrial loads, but not all.

If total average demand stays below about 1.0 m³/min at the working pressure and peaks are covered by the tank/dryer buffer, a 10HP PMVF unit is well matched. If continuous demand exceeds 1.1 m³/min at 8 bar, consider 11–15HP or multiple staged packages.

Air Quality And Filtration

Even with an integrated refrigerant dryer, the required filtration depends on the process.

• General pneumatic tools: particulate prefilter + coalescing filter + refrigerator dryer.

• Automotive painting: dryer, coalescing/oil-removal filter, fine particulate filter, gun-side mini trap; verify oil residue and dew point with paint specification.

• Laser cutting: low moisture and low oil are critical. Many integrated packages include high-precision filters; for high-power metal cutting, specify dryer capacity, particulate grade, and oil-control class separately.

• Food, pharma, electronics: oil-injected PM screw is usually not enough. Use oil-free screw with desiccant drying and validate ISO 8573-1 Class 0 where required.

Typical integrated oil-injected screw discharge contains some oil aerosol; published examples list a few ppm before final filtration, so downstream filters determine final air class.

Installation And Mobility Tips

• Place the portable unit on a level floor with vibration pads if the chassis has rigid wheels.

• Keep at least 60–90 cm clearance around panels, cooler, and electrical enclosure for airflow.

• Intake air should be cool, clean, and away from grinding dust, vehicle exhaust, and paint overspray.

• Connect the dryer first after the receiver, then filters in correct order: particulate → coalescing → fine/carbon if required.

• Set main pressure by actual tool/laser demand, not maximum airend pressure, to save energy and reduce component stress.

• For mobile use between bays, confirm total weight with tank and dryer; a 300L integrated unit can be several hundred kilograms and may need pallet truck or forklift rather than manual wheels.

Maintenance Plan For 7.5kW PMVF Portable Screw

PMVF units are lower-maintenance than pistons but still require scheduled service:

• Check compressor oil level daily; use manufacturer-approved screw oil. Change oil and oil filter per hours or annually under heavy use.

• Monitor oil separator differential pressure; replace separator element before pressure penalty increases energy use.

• Clean or replace intake air filter monthly in dusty workshops, quarterly in clean rooms.

• Inspect VFD cooling fan, radiator/aftercooler fins, and dryer condenser; dust reduces FAD and raises temperature.

• Test automatic drains on tank, dryer, and filters; manual-drain units should be drained each shift.

• Review controller alarms, runtime, load percentage, and power trends; VSD data helps detect leaks and oversizing.

• Verify belt tension only on belt-driven variants; many PMVF units are direct-coupled and need less belt service.

• Update controller parameters and protection settings during scheduled service; do not disable thermal, pressure, and phase-loss alarms.

Energy Savings Expectation

Fixed-speed compressors often run unloaded when demand drops, and no-load motor consumption can be substantial. VSD/PM systems reduce speed and power at partial load. Vendor data for PM VSD screws quotes wide ranges; some 10HP-class materials claim 8% and above baseline savings, while others quote 30–40% in variable-demand conditions compared with fixed load/unload operation. Real savings depend on load factor, pressure setting, ambient temperature, leaks, and dryer operation. A simple payback check should compare:

• Current piston/fixed compressor power hours

• Average CFM demand versus nameplate FAD

• Leakage percentage

• Required pressure versus actual pressure

• Dryer energy and maintenance

If the compressor runs several hours per day with fluctuating demand, PMVF usually beats fixed-speed piston or DOL screw. If it runs a few hours per week at near-full load, a simpler fixed screw may be cheaper upfront.

Frequently Asked Questions

Is a 7.5kW 10HP PMVF screw enough for a small laser cutting machine?

It can be enough for low-to-moderate air-assist duties, purging, and auxiliary air. For fiber laser cutting of metal at higher power and thicker sections, air volume and purity requirements increase; verify nozzle consumption at the required bar and choose dryer/filter grade accordingly. Some integrated 10HP packages are marketed for laser support, but high-production cutting may need 11–22kW or更高.

What pressure should I choose, 8, 10, or 13 bar?

Choose 8 bar for general tools, inflation, and light spraying. Choose 10 bar for longer pipelines, higher-pressure impacts, and many laser/support duties. Choose 12–13 bar only if specific equipment requires it, because FAD drops as pressure rises; a 10HP unit may deliver only about 0.72–0.75 m³/min at 12–13 bar.

Does the integrated dryer remove oil?

A refrigerant dryer removes moisture and reduces dew point, but an oil-injected screw still produces oil aerosol. Coalescing and particulate filters remove most oil mist; activated carbon reduces odor/trace oil. For oil-free requirements, specify an oil-free airend and appropriate drying, not a standard PMVF oil-injected package.

How portable is a 7.5kW screw with tank and dryer?

Compact VSD-only cabinets can be moved by a few people or pallet truck; full 4-in-1 units with 300L tank, dryer, and filters can weigh several hundred kilograms and are “portable” mainly between indoor bays with forklift/wheels. Confirm dimensions and weight before placing in elevators or mobile trailers.

Is PMVF better than a normal 10HP fixed screw?

For variable demand, yes. The VSD matches flow to demand, reduces unloaded power, and soft-starts the motor. For a steady 24-hour load at constant CFM, a fixed screw can be simpler and cheaper, but PMVF still often saves energy through better part-load control and motor efficiency.

What size air receiver is best with 10HP portable screw?

For stable pressure in a workshop with intermittent tools, 100–210L is often sufficient. For multiple stations, laser buffering, or frequent peak demand, 300L+ improves continuity but increases footprint. Because screw output is continuous, oversized tanks are less critical than with pistons.

What noise level should I expect?

Enclosed PMVF packages vary by design and load; small VSD screw cabinets may be listed around 60–76 dB(A) depending on enclosure, airend speed, and dryer fan. Request dB(A) at rated distance and full load, not idle.

A 7.5kW 10HP 380V PMVF portable screw with integrated dryer is a strong choice for workshops and small industrial systems that need stable pressure, dry clean air, low part-load energy use, and compact installation. Prioritize verified FAD at working pressure, dryer dew point, filter class, tank size for the site, and proper 380V three-phase electrical sizing rather than maximum bar or horsepower alone.