Oil-Injected Rotary Screw Air Compressors

CMN/A Fixed-Speed & CMN/PV Permanent Magnet VSD Series

Two series of industrial oil-injected rotary screw air compressors covering 10–340 HP, operating pressures from 116 to 232 PSI, and free-air delivery reaching approximately 1,500+ CFM. Residual oil carryover ≤ 2 ppm. Designed for continuous industrial operation in ambient temperatures up to 55°C / 131°F.

10–340 HP
Installed Motor Power
116–232 PSI
Working Pressure
~1,500+ CFM
Max Free Air Delivery
≤2 ppm
Residual Oil Carryover
131°F / 55°C
Max Ambient Temperature

compressor series

Choose Your Compressor Series: Fixed-Speed or PM VSD

Both series use oil-injected rotary screw airend technology with a shaft-seal-free design and ≤ 2 ppm residual oil carryover. The difference is how each manages motor speed — and that affects how well each matches your operating pattern.

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Fixed-Speed Series

Model Range

CMN/A Series

Fixed-Speed Oil-Injected Rotary Screw Compressors

The CMN/A runs at a constant motor speed. Air delivery is controlled through an inlet valve and load/unload cycling. This is a straightforward, well-proven control architecture suited to operations where compressed air demand is relatively stable throughout the production cycle.

CMN/A Series

Fixed-Speed
10–340 HP 7.5–250 kW
116–232 PSI 8–16 bar
39–1,514 CFM 1.11–42.88 m³/min
CMN08A–CMN250A 14 model sizes

Typically suited for:

  • Stable, predictable compressed air demand
  • Long continuous production cycles near full load
  • Applications with simpler control requirements
  • Facilities evaluating total investment vs. operating hours
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ϟ PM VSD Series

Model Range

CMN/PV Series

Permanent Magnet VSD Oil-Injected Rotary Screw Compressors

The CMN/PV uses a permanent magnet synchronous motor (PMSM) controlled by a variable frequency drive. Motor speed adjusts continuously to match actual air demand. When demand drops, motor speed decreases — the compressor delivers closer to what is actually required rather than load/unload cycling.

CMN/PV Series

PM VSD
10–340 HP 7.5–250 kW
116–232 PSI 8–16 bar
10–1,561 CFM 0.29–44.20 m³/min
CMN08PV–CMN250PV 14 model sizes

Typically suited for:

  • Variable or shifting air demand across the day or between shifts
  • Production lines with frequent load changes
  • Facilities where compressor runs at partial load for extended periods
  • Operations where tighter pressure control reduces downstream waste

Engineering Comparison

Fixed-Speed vs. Permanent Magnet VSD: Engineering Comparison

The right choice depends on your specific demand profile, operating hours, and electrical environment — not a blanket rule. This table outlines the engineering differences to help frame that decision.

Attribute CMN/A — Fixed-Speed CMN/PV — PM VSD
Motor type Standard induction motor at constant speed Permanent magnet synchronous motor (PMSM) with VFD speed control
Demand profile match Fixed output — load/unload valve controls delivery Motor speed adjusts continuously to track actual demand
Part-load operation Motor continues running at full speed during unloaded periods, energy is consumed without producing air Motor slows proportionally; energy draw reduces when output is below maximum
Pressure control Wider pressure band between load and unload setpoints Tighter pressure band; delivery tracks setpoint more closely
Initial investment Generally lower purchase cost Higher initial cost due to VFD and PMSM
Control architecture Simpler — mechanical inlet valve, standard controls More complex — VFD, motor driver, inverter thermal management
Best operating pattern High utilization factor; demand consistently near rated capacity; minimal variation across shifts Demand varies across the shift or between production modes; meaningful idle or part-load periods
Typical application examples Dedicated process lines, continuous manufacturing, high-duty sandblasting Multi-shift production, facilities with varying tool usage, systems serving mixed processes

Engineering Features That Affect Compressor Performance

These are the design characteristics that factory-stated data supports. Each point is explained in terms of its engineering basis and what it means operationally.

Shaft-Seal-Free Airend Architecture

Conventional rotary screw airends use a shaft seal where the drive shaft exits the compression chamber — a known potential leak point for oil. The CMN airend eliminates this conventional shaft-seal leakage path, removing one source of potential external oil migration. This affects long-term oil system integrity and reduces one maintenance-related inspection point.

Designed for High Free-Air Delivery

The airend rotor geometry is engineered to increase free-air delivery for a given installed motor size. Manufacturer-stated data indicates improved volumetric output relative to conventional designs under specified test conditions — specific test basis and reference conditions available upon request. Do not interpret this as a direct competitive comparison without confirmed data.

≤ 2 ppm Residual Oil Carryover

After the air/oil separation stage, residual oil carryover is manufacturer-stated at ≤ 2 ppm by weight. This is the carryover level at the compressor outlet — it is not an "oil-free" classification. Final air quality at point-of-use depends on the downstream treatment system (dryer, coalescing filter, activated carbon filter) and the applicable ISO 8573 air quality requirements for your process.

High-Ambient Operation — Up to 55°C / 131°F

Manufacturer-stated ambient temperature rating is continuous operation up to 55°C (131°F). Maximum unit operating temperature is stated as ≤ 92°C (198°F). This is relevant for hot production environments, facilities without full climate control, and installations in warm-climate regions. Adequate ventilation and cooling airflow to the installation space remain necessary regardless of ambient rating.

Air-Cooled Cooling System

Both series use an air-cooled cooling system with a dedicated cooling fan. Fan motor power ranges from 0.12 kW (smaller models) up to 5.5 kW × 2 fans on the 250 kW models. Adequate installation space for cooling airflow is required — the machine must not recirculate its own exhaust air. Consult dimensional data for minimum clearance requirements.

Continuous Industrial Operation

Rotary screw compressors are designed for 100% duty cycle — continuous running is their normal operating state. The CMN series is intended for sustained industrial production environments. Unlike reciprocating piston compressors, these units are not designed for intermittent start-stop cycling as a primary control strategy.

What Does “Micro-Oil” Mean — and Is It Oil-Free?

Direct answer: A micro-oil screw compressor is an oil-injected (oil-lubricated) rotary screw compressor with an advanced oil separation system that achieves low residual oil carryover — typically ≤ 2 ppm at the outlet. It is not an oil-free compressor. Oil is present in the compression chamber during every compression cycle.

In a micro-oil (oil-injected) rotary screw compressor, oil is deliberately introduced into the compression chamber. It serves four functions simultaneously: it lubricates the rotor contact zones, seals the small clearances between the male and female rotors, removes heat generated during compression, and damps mechanical noise. After the compression stage, the air/oil mixture passes through a multi-stage separation system — centrifugal separation followed by a coalescing separator element. Most of the oil is recovered and recirculated. Residual carryover in the compressed air is what the ≤ 2 ppm specification describes.

“Micro-oil” refers to that low residual carryover figure — it does not mean the air is oil-free. For applications requiring oil-free compressed air (pharmaceutical, food-direct contact, electronics manufacturing, ISO 8573-1 Class 0), an oil-free air compressor is required.

Characteristic Micro-Oil (Oil-Injected) Oil-Free Compressor
Compression chamber lubrication Oil injected — present during compression No oil in the compression chamber
Residual oil at outlet ≤ 2 ppm (manufacturer-stated) — not zero Typically ISO 8573-1 Class 0 achievable
Typical applications General manufacturing, pneumatic tools, sandblasting, conveying, automation Food contact, pharma, electronics, paint-line (where zero oil is required)
Air treatment needed Dryer, coalescing filter, activated carbon for sensitive processes Dryer and particulate filter; no oil-removal filtration required
Typical purchase cost Lower for equivalent HP/kW Higher; multi-stage or dry-screw technology

How an Oil-Injected Rotary Screw Air Compressor Works

Understanding the compression cycle helps explain both the performance characteristics and the role each component plays in the system.

CMN A Series oil-injected rotary screw air compressor
Oil-Injected Screw Compressor
1
Ambient Air

Air enters the compressor package from the surrounding environment.

2
Intake Filter

A multi-stage intake filter removes airborne particulates before they reach the airend.

3
Inlet Valve

The inlet valve controls the volume of admitted air. Fixed-speed units modulate flow; VSD units reduce the need for heavy throttling.

4
Screw Airend +
Oil Injection

Male and female helical rotors mesh to reduce air volume and compress it. Oil continuously lubricates, seals internal clearances and absorbs heat of compression.

5
Air/Oil Separator

The discharged air-oil mixture enters the separator, where centrifugal action and a coalescing element remove the bulk of the oil from the air stream.

6
Aftercooler

Compressed air passes through the aftercooler to reduce discharge temperature, and condensed moisture is removed downstream.

7
Compressed Air
Outlet

Clean compressed air leaves the package for the plant air system and any downstream dryers or filters.

Compression
Cycle Summary

Oil injection improves lubrication, sealing and cooling.

Single-stage compression achieves high efficiency without intercooling.

Recovered oil is filtered, cooled and recirculated.

Final air treatment such as dryers and filters occurs downstream.

Technical Specifications

Full parameter data for both series. CFM, PSI, and HP are primary. Metric units included for reference. Data transcribed from manufacturer technical documentation.

Technical Specifications

Full parameter data for both series. CFM, PSI, and HP are primary. Metric units included for reference. Data transcribed from manufacturer technical documentation.

Model Working Pressure FAD (Free Air Delivery) Power Noise Oil Carryover Weight Cooling Fan Air Outlet Dimensions L×W×H
MPa / bar PSI m³/min CFM kW HP dB(A) PPM kg kW inch / DN mm
CMN08A — 10 HP / 7.5 kW
CMN08A0.8 / 81161.31467.51062≤23020.12×13/4"990×640×980
CMN08A1.0 / 101451.11397.51062≤23020.12×13/4"990×640×980
CMN11A — 15 HP / 11 kW
CMN11A0.8 / 81161.8164111562≤23220.12×13/4"990×640×980
CMN11A1.0 / 101451.5254111562≤23220.12×13/4"990×640×980
CMN11A1.25 / 12.51811.3548111562≤23220.12×13/4"990×640×980
CMN15A — 20 HP / 15 kW
CMN15A0.8 / 81162.6092152063≤25050.37×11"1250×790×1290
CMN15A1.0 / 101452.3583152063≤25050.37×11"1250×790×1290
CMN15A1.25 / 12.51811.7361152063≤25050.37×11"1250×790×1290
CMN18A — 25 HP / 18.5 kW
CMN18A0.8 / 81161.214318.52565≤25350.37×11"1250×790×1290
CMN18A1.0 / 101453.3011718.52565≤25350.37×11"1250×790×1290
CMN18A1.25 / 12.51812.9010218.52565≤25350.37×11"1250×790×1290
CMN18A1.6 / 162322.408518.52565≤25350.37×11"1250×790×1290
CMN22A — 30 HP / 22 kW
CMN22A0.8 / 81163.90138223065≤25650.37×11"1250×790×1290
CMN22A1.0 / 101453.50124223065≤25650.37×11"1250×790×1290
CMN22A1.25 / 12.51812.90102223065≤25650.37×11"1250×790×1290
CMN22A1.6 / 162322.4085223065≤25650.37×11"1250×790×1290
CMN30A — 40 HP / 30 kW
CMN30A0.8 / 81164.92174304066≤27301.3×11-1/2"1500×950×1420
CMN30A1.0 / 101454.22149304066≤27301.3×11-1/2"1500×950×1420
CMN30A1.25 / 12.51813.81135304066≤27301.3×11-1/2"1500×950×1420
CMN30A1.6 / 162323.04107304066≤27301.3×11-1/2"1500×950×1420
CMN37A — 50 HP / 37 kW
CMN37A0.8 / 81166.30222375067≤27701.3×11-1/2"1500×950×1420
CMN37A1.0 / 101455.50194375067≤27701.3×11-1/2"1500×950×1420
CMN37A1.25 / 12.51815.10180375067≤27701.3×11-1/2"1500×950×1420
CMN37A1.6 / 162323.60127375067≤27701.3×11-1/2"1500×950×1420
CMN45A — 60 HP / 45 kW
CMN45A0.8 / 81167.60265456068≤211961.8×12"1850×1105×1600
CMN45A1.0 / 101456.30222456068≤211961.8×12"1850×1105×1600
CMN45A1.25 / 12.51815.84206456068≤211961.8×12"1850×1105×1600
CMN45A1.6 / 162324.53160456068≤211961.8×12"1850×1105×1600
CMN55A — 75 HP / 55 kW
CMN55A0.8 / 811610.30364557570≤212901.8×12"1850×1105×1600
CMN55A1.0 / 101459.10321557570≤212901.8×12"1850×1105×1600
CMN55A1.25 / 12.51817.60268557570≤212901.8×12"1850×1105×1600
CMN55A1.6 / 162325.80205557570≤212901.8×12"1850×1105×1600
CMN75A — 100 HP / 75 kW
CMN75A0.8 / 811612.504457510073≤215702.2×12"1900×1200×1660
CMN75A1.0 / 1014511.504067510073≤215702.2×12"1900×1200×1660
CMN75A1.25 / 12.51819.943517510073≤215702.2×12"1900×1200×1660
CMN75A1.6 / 162326.902447510073≤215702.2×12"1900×1200×1660
CMN90A — 125 HP / 90 kW
CMN90A0.8 / 811616.115699012573≤222700.37×1DN652000×1320×1905
CMN90A1.0 / 1014514.525139012573≤222704×1DN652000×1320×1905
CMN90A1.25 / 12.518112.304349012573≤222704×1DN652000×1320×1905
CMN90A1.6 / 162329.503359012573≤222704×1DN652000×1320×1905
CMN110A — 150 HP / 110 kW
CMN110A0.8 / 811620.1071011015078≤222900.37×1DN652000×1370×1980
CMN110A1.0 / 1014517.1060411015078≤222904×1DN652000×1370×1980
CMN110A1.25 / 12.518115.2253711015078≤222904×1DN652000×1370×1980
CMN110A1.6 / 1623211.6041011015078≤222904×1DN652000×1370×1980
CMN132A — 180 HP / 132 kW
CMN132A0.8 / 811623.1081613218078≤225500.37×1DN652000×1370×1980
CMN132A1.0 / 1014520.3872013218078≤225504×1DN652000×1370×1980
CMN132A1.25 / 12.518118.2964613218078≤225504×1DN652000×1370×1980
CMN132A1.6 / 16232[DATA TO CONFIRM][DATA TO CONFIRM]13218078≤225504×1DN652000×1370×1980
CMN160A — 220 HP / 160 kW
CMN160A0.8 / 811628.85101916022078≤238003.5×2DN802950×1720×2350
CMN160A1.0 / 1014524.5286616022078≤238003.5×2DN802950×1720×2350
CMN160A1.25 / 12.518122.1778316022078≤238003.5×2DN802950×1720×2350
CMN160A1.6 / 1623219.1067416022078≤238003.5×2DN802950×1720×2350
CMN200A — 270 HP / 200 kW
CMN200A0.8 / 811636.63129320027078≤241005.5×2DN1003100×1800×2322
CMN200A1.0 / 1014532.70115520027078≤241005.5×2DN1003100×1800×2322
CMN200A1.25 / 12.518127.7297920027078≤241005.5×2DN1003100×1800×2322
CMN200A1.6 / 1623221.9077320027078≤241005.5×2DN1003100×1800×2322
CMN250A — 340 HP / 250 kW
CMN250A0.8 / 811642.88151425034078≤245005.5×2DN1003100×1800×2322
CMN250A1.0 / 1014539.00137725034078≤245005.5×2DN1003100×1800×2322
CMN250A1.25 / 12.518134.64122325034078≤245005.5×2DN1003100×1800×2322
CMN250A1.6 / 1623227.4096725034078≤245005.5×2DN1003100×1800×2322

Gas supply (compressed air delivery) temperature: ≤ ambient + 15°C. Oil carryover ≤ 2 ppm applies across the range (manufacturer-stated). Performance values are subject to operating conditions and final technical confirmation. Test basis available upon request.

Model Working Pressure FAD Range (VSD) Power Noise Oil Carryover Weight Cooling Fan Air Outlet Dimensions L×W×H
MPa / bar PSI m³/min CFM kW HP dB(A) PPM kg kW inch / DN mm
CMN08PV — 10 HP / 7.5 kW PM VSD
CMN08PV0.8 / 81160.34–1.3812–497.51062≤23170.12×13/4"990×640×980
CMN08PV1.0 / 101450.23–1.1710–417.51062≤23170.12×13/4"990×640×980
CMN08PV1.25 / 12.51810.20–0.67 [DATA TO CONFIRM range end]7.51062≤23170.12×13/4"990×640×980
CMN11PV — 15 HP / 11 kW PM VSD
CMN11PV0.8 / 81160.48–1.9017–67111562≤23370.12×13/4"990×640×980
CMN11PV1.0 / 101450.40–1.6014–57111562≤23370.12×13/4"990×640×980
CMN11PV1.25 / 12.51810.35–1.4212–50111562≤23370.12×13/4"990×640×980
CMN15PV — 20 HP / 15 kW PM VSD
CMN15PV0.8 / 81160.68–2.7324–96152063≤26350.55×11"1520×900×1460
CMN15PV1.0 / 101450.65–2.5023–88152063≤26350.55×11"1520×900×1460
CMN15PV1.25 / 12.51810.43–1.8015–64152063≤26350.55×11"1520×900×1460
CMN15PV1.6 / 162320.33–1.3012–46152063≤26350.55×11"1520×900×1460
CMN18PV — 25 HP / 18.5 kW PM VSD
CMN18PV0.8 / 81160.88–3.5031–12418.52565≤26500.55×11"1520×900×1460
CMN18PV1.0 / 101450.78–3.1028–10918.52565≤26500.55×11"1520×900×1460
CMN18PV1.25 / 12.51810.63–2.5022–8818.52565≤26500.55×11"1520×900×1460
CMN18PV1.6 / 162320.44–1.7516–6218.52565≤26500.55×11"1520×900×1460
CMN22PV — 30 HP / 22 kW PM VSD
CMN22PV0.8 / 81161.03–4.1036–145223065≤26650.55×11"1520×900×1460
CMN22PV1.0 / 101450.93–3.7033–131223065≤26650.55×11"1520×900×1460
CMN22PV1.25 / 12.51810.78–3.1028–109223065≤26650.55×11"1520×900×1460
CMN22PV1.6 / 162320.63–2.5023–88223065≤26650.55×11"1520×900×1460
CMN30PV — 40 HP / 30 kW PM VSD
CMN30PV0.8 / 81161.30–5.2046–184304066≤210101.3×11-1/2"1900×950×1620
CMN30PV1.0 / 101451.11–4.4339–156304066≤210101.3×11-1/2"1900×950×1620
CMN30PV1.25 / 12.51811.00–4.0035–141304066≤210101.3×11-1/2"1900×950×1620
CMN30PV1.6 / 162320.80–3.2028–113304066≤210101.3×11-1/2"1900×950×1620
CMN37PV — 50 HP / 37 kW PM VSD
CMN37PV0.8 / 81161.65–6.6058–233375067≤210301.3×11-1/2"1900×950×1620
CMN37PV1.0 / 101451.45–5.8051–205375067≤210301.3×11-1/2"1900×950×1620
CMN37PV1.25 / 12.51811.33–5.4047–191375067≤210301.3×11-1/2"1900×950×1620
CMN37PV1.6 / 162320.95–3.8034–134375067≤210301.3×11-1/2"1900×950×1620
CMN45PV — 60 HP / 45 kW PM VSD
CMN45PV0.8 / 81161.98–7.9070–279456068≤211761.8×12"2070×1100×1790
CMN45PV1.0 / 101451.65–6.6058–233456068≤211761.8×12"2070×1100×1790
CMN45PV1.25 / 12.51811.55–6.2055–219456068≤211761.8×12"2070×1100×1790
CMN45PV1.6 / 162321.20–4.8042–169456068≤211761.8×12"2070×1100×1790
CMN55PV — 75 HP / 55 kW PM VSD
CMN55PV0.8 / 81162.70–10.8095–381557570≤212301.8×12"2070×1100×1790
CMN55PV1.0 / 101452.40–9.6085–339557570≤212301.8×12"2070×1100×1790
CMN55PV1.25 / 12.51812.00–8.0071–282557570≤212301.8×12"2070×1100×1790
CMN55PV1.6 / 162321.53–6.1054–215557570≤212301.8×12"2070×1100×1790
CMN75PV — 100 HP / 75 kW PM VSD
CMN75PV0.8 / 81163.31–13.23117–4677510073≤214402.2×12"2270×1200×1800
CMN75PV1.0 / 101453.03–12.10107–4277510073≤214402.2×12"2270×1200×1800
CMN75PV1.25 / 12.51812.61–10.4492–3697510073≤214402.2×12"2270×1200×1800
CMN75PV1.6 / 162321.81–7.2564–2567510073≤214402.2×12"2270×1200×1800
CMN90PV — 125 HP / 90 kW PM VSD
CMN90PV0.8 / 81164.23–16.90149–5979012573≤218000.37×1DN652150×1340×2140
CMN90PV1.0 / 101453.81–15.25135–5389012573≤218004×1DN652150×1340×2140
CMN90PV1.25 / 12.51813.23–12.90114–4569012573≤218004×1DN652150×1340×2140
CMN90PV1.6 / 162322.50–10.0088–3539012573≤218004×1DN652150×1340×2140
CMN110PV — 150 HP / 110 kW PM VSD
CMN110PV0.8 / 81165.28–18.00186–63611015078≤220800.37×1DN652150×1340×2140
CMN110PV1.0 / 101454.50–16.00159–56511015078≤220804×1DN652150×1340×2140
CMN110PV1.25 / 12.51814.00–16.00141–56511015078≤220804×1DN652150×1340×2140
CMN110PV1.6 / 162323.05–12.20108–43111015078≤220804×1DN652150×1340×2140
CMN132PV — 180 HP / 132 kW PM VSD
CMN132PV0.8 / 81166.08–24.30215–85813218078≤222000.37×1DN652460×1370×1980
CMN132PV1.0 / 101455.35–21.40188–75613218078≤222004×1DN652460×1370×1980
CMN132PV1.25 / 12.51814.80–19.20169–67813218078≤222004×1DN652460×1370×1980
CMN132PV1.6 / 162323.98–15.90141–56113218078≤222004×1DN652460×1370×1980
CMN160PV — 220 HP / 160 kW PM VSD
CMN160PV0.8 / 81167.58–30.30268–1,07016022078≤240003.5×2DN802950×1720×2350
CMN160PV1.0 / 101456.45–25.80228–91116022078≤240003.5×2DN802950×1720×2350
CMN160PV1.25 / 12.51815.83–23.30206–82316022078≤240003.5×2DN802950×1720×2350
CMN200PV — 270 HP / 200 kW PM VSD
CMN200PV0.8 / 81169.63–38.50340–1,35920027078≤242005.5×2DN1003270×1800×2322
CMN200PV1.0 / 101458.60–34.40304–1,21520027078≤242005.5×2DN1003270×1800×2322
CMN200PV1.25 / 12.51817.30–29.10258–1,02820027078≤242005.5×2DN1003270×1800×2322
CMN250PV — 340 HP / 250 kW PM VSD
CMN250PV0.8 / 811611.10–44.20392–1,56125034078≤244505.5×2DN1003270×1800×2322
CMN250PV1.0 / 1014510.00–40.20353–1,42025034078≤244505.5×2DN1003270×1800×2322
CMN250PV1.25 / 12.51818.93–35.70315–1,26125034078≤244505.5×2DN1003270×1800×2322

FAD values shown as manufacturer-stated operating range at rated pressure. Gas supply temperature: ≤ ambient + 15°C. Oil carryover ≤ 2 ppm applies across the range (manufacturer-stated). CMN/PV delivers variable output across the stated range as motor speed modulates to match demand. Performance values are subject to operating conditions and final technical confirmation. Test basis available upon request.

Quick Reference

Application Matrix — Oil-Injected Rotary Screw Compressors

The series recommendations below reflect typical demand patterns for each application and should be verified against your actual operating conditions.

Series recommendations indicate typical suitability based on demand patterns described. Final selection should be confirmed against your actual measured flow, pressure, and operating profile. “Oil-injected” compressed air used in food-contact or pharmaceutical processes requires engineering confirmation of the full air treatment system.

Quick Reference

Application Matrix — Oil-Injected Rotary Screw Compressors

The series recommendations below reflect typical demand patterns for each application and should be verified against your actual operating conditions.

Initial Equipment

Fixed-speed (CMN/A) generally has a lower purchase price than an equivalent PM VSD (CMN/PV) due to the simpler motor and control architecture. The cost differential narrows at larger sizes.

Electricity Cost

For a compressor running 6,000+ hours per year, electricity cost over 5–10 years can substantially exceed the purchase price. The relevance of VSD energy savings depends on how often the compressor operates below full load — demand profile determines the actual savings, not nameplate ratings.

Unloaded Running

A fixed-speed compressor consumes approximately 20–40% of full-load power when running unloaded (no air production). If a compressor unloads frequently, this represents energy cost without production output. A VSD eliminates the unloaded state by reducing motor speed instead.

Excess Pressure

Operating at higher pressure than required wastes energy. Every 2 PSI of excess outlet pressure adds approximately 1% to power consumption (as a general industry reference — your system characteristics may vary). Set pressure to what the process actually needs.

Air Leaks

Compressed air leaks are often 20–30% of total compressor output in poorly maintained systems. A 1/8" leak at 100 PSI can waste significant CFM continuously. Reducing leaks reduces the required compressor output — often the most cost-effective "upgrade" available.

Maintenance

Scheduled maintenance on oil, separator elements, filters, and drive components is a predictable cost. The CMN/PV's PM motor has no brushes or commutator, reducing motor-side maintenance. Both series require periodic separator element, oil filter, and air filter service.

Engineering Questions

Frequently Asked Questions

What is an oil-injected rotary screw air compressor?

An oil-injected rotary screw air compressor compresses air using two helical rotors (male and female) that turn in opposite directions inside a precision housing. Oil is injected into the compression chamber during every cycle — it lubricates the rotor contact zones, seals internal clearances to minimize leakback, cools the air during compression, and reduces mechanical noise. After compression, a multi-stage separation system recovers and recirculates the oil. The compressed air exits with a small residual oil carryover, which is then addressed by downstream filters. “Oil-injected,” “oil-lubricated,” and “oil-flooded” all describe the same technology — the oil is in the compression chamber.

What does "micro-oil screw compressor" mean?

“Micro-oil” refers to the low residual oil carryover achieved after the air/oil separation stage — typically ≤ 2 ppm by weight at the compressor outlet. It indicates that the separation system is effective at recovering oil from the compressed air stream. It does not mean the compressor operates without oil — oil is injected into the compression chamber during every cycle. The term describes the carryover level, not the compression mechanism.

When should I choose a permanent magnet VSD air compressor?

A PM VSD compressor is typically advantageous when: air demand varies meaningfully across the shift or between production modes; the compressor would otherwise run unloaded for a significant portion of its operating hours; a tighter system pressure band is beneficial (VSD maintains pressure more precisely than a fixed-speed load/unload cycle); or operating hours are high enough that energy savings over time offset the higher purchase cost. If your demand is consistently close to the compressor’s rated output and varies little, the energy advantage of VSD is smaller and the economics may favor fixed-speed.

How do I calculate how many CFM my plant needs?

The most accurate approach is a measured demand survey on an existing system using a data logger to record actual consumption over a representative production period. For new installations, list all pneumatic tools and equipment by CFM requirement and apply a diversity factor reflecting how many items operate simultaneously. Summing all nameplate CFM ratings significantly overestimates actual demand. Add 20–30% for system leaks, pressure drop across treatment equipment, and future capacity margin. Contact us with your equipment list and we can assist with the sizing calculation.

What does ≤ 2 ppm oil carryover mean for my process?

≤ 2 ppm (parts per million by weight) is the manufacturer-stated maximum residual oil content in the compressed air at the compressor outlet, after the air/oil separation stage. This is not zero — it is a low but measurable level. For general pneumatic tools and most industrial automation, this level is typically acceptable, particularly with a standard coalescing filter downstream. For applications with low oil tolerance — spray painting, precision instrumentation, food-adjacent processes, electronics — the final air quality must be confirmed against the ISO 8573-1 class required by the process, and the downstream treatment system must be designed accordingly.

Is a micro-oil screw compressor oil-free?

No. A micro-oil screw compressor is an oil-injected (oil-lubricated) compressor. Oil is present in the compression chamber throughout operation. The “micro” qualifier refers to the low residual oil carryover at the outlet — ≤ 2 ppm — not the absence of oil. If your application requires ISO 8573-1 Class 0 oil-free air (pharmaceutical, food-direct contact, certain electronics), a true oil-free compressor is required. For most general manufacturing, pneumatic tools, and industrial processes, ≤ 2 ppm at the compressor outlet — with appropriate downstream filtration — is adequate; confirm with your process specification.

What is the difference between fixed-speed and VSD rotary screw compressors?

A fixed-speed compressor runs its motor at a single constant speed. Air delivery is regulated by an inlet valve and load/unload cycling. When demand drops below the compressor’s output, the machine unloads — the motor continues running at full speed, but no useful air is produced. A VSD (variable speed drive) compressor adjusts motor speed continuously to match actual demand. When demand decreases, the motor slows and power consumption reduces proportionally. The trade-off is higher initial cost and more complex electronics. Fixed-speed is often cost-effective when demand stays consistently near full capacity; VSD typically shows greater energy benefit when the compressor runs at partial load for extended periods.

Can the CMN compressor operate at 131°F / 55°C ambient temperature?

Yes — the CMN/A and CMN/PV are manufacturer-rated for continuous operation in ambient temperatures up to 55°C (131°F). Maximum unit operating temperature is stated at ≤ 92°C (198°F). This makes both series relevant for hot production environments, poorly ventilated equipment rooms, and warm-climate installations. Adequate ventilation is still required — the installation space must be able to remove the heat the machine rejects, and cooling air must be able to reach the compressor’s intake without recirculating the hot exhaust air.

Do I need a dryer and filters after an oil-injected compressor?

For most industrial applications: yes. The aftercooler built into the compressor package reduces air temperature and allows some condensate to drop out, but it does not deliver dried or filtered air adequate for most processes. A refrigerated dryer is standard for general manufacturing use. Coalescing filters remove residual oil aerosols. For sensitive processes — instrumentation, spray painting, laser assist, food-adjacent lines — additional treatment (desiccant dryer, activated carbon filter, sterile filter) is typically required. The specific configuration depends on the ISO 8573-1 class your process demands.

Can you supply compressors configured for 60 Hz / US and Canadian voltage?

For most industrial applications: yes. The aftercooler built into the compressor package reduces air temperature and allows some condensate to drop out, but it does not deliver dried or filtered air adequate for most processes. A refrigerated dryer is standard for general manufacturing use. Coalescing filters remove residual oil aerosols. For sensitive processes — instrumentation, spray painting, laser assist, food-adjacent lines — additional treatment (desiccant dryer, activated carbon filter, sterile filter) is typically required. The specific configuration depends on the ISO 8573-1 class your process demands.

What information do I need to provide to get a compressor recommendation?

The minimum information needed is: required airflow (CFM or m³/min), required working pressure (PSI or bar), available electrical supply (voltage / phase / frequency), and a brief description of the application. For a more accurate recommendation, also include: demand pattern (continuous or variable), operating hours per day, maximum ambient temperature, site altitude, and any air quality requirements. The more complete the operating conditions provided, the more precise the recommendation.

Before Requesting a Compressor Quote

Gathering this information before contacting us allows for a faster, more accurate model recommendation.

Required airflow — CFM or m³/min at working pressure

Required working pressure — PSI or bar

Demand pattern — continuous / variable / cyclic

Operating hours per day and days per week

Available voltage — 208 / 230 / 460 / 575 V or other

Phase and frequency — 3-phase / 50 Hz or 60 Hz

Maximum ambient temperature at installation site (°F or °C)

Altitude above sea level (if above 1,000 ft / 300 m)

Indoor or outdoor installation; ventilation available?

Required air quality — ISO 8573 class or process description

Existing air receiver size (if any)

Existing dryers, filters, or treatment (if any)

Available floor space — dimensions or restriction

Application — what does the compressed air power?