EP-CMW4.5-1.2 Oil-Free Scroll Air Compressor
The EP-CMW4.5-1.2 delivers 360 L/min of certified oil-free air at 1.2 MPa from a 4.5 kW permanent magnet scroll drive — the mid-range capacity point in the world’s first 1.2 MPa oil-free scroll compressor series, purpose-built for precision coating, high-pressure instrument supply, and specialty industrial processes where native 1.2 MPa air produces measurably better process outcomes than regulated-down lower-pressure sources.
Native 1.2 MPa vs. Regulated-Down: Why the Source Pressure Matters to Process Quality
When engineers first encounter the EP-CMW4.5-1.2, the question is sometimes framed as: "Can't I just take a 1.6 MPa compressor and regulate it down to 1.2 MPa?" The answer is technically yes -- but the process outcomes are not equivalent, and for precision applications the difference is measurable.
A pressure regulator reduces supply pressure by throttling flow. What it does not reduce is the pressure variation -- the band between minimum and maximum downstream pressure as the upstream compressor cycles. A reciprocating compressor at 1.6 MPa with a regulator set to 1.2 MPa delivers downstream pressure that varies across the regulator's hysteresis band. That variation is typically 0.05 to 0.15 MPa for a standard industrial regulator. For most industrial pneumatic tools, this is acceptable. For precision spray equipment, high-pressure instrument calibration, and certain analytical processes, it is not.
A native 1.2 MPa source delivers consistent pressure directly at the rated working point. A regulated-down source delivers a pressure band centred approximately at 1.2 MPa, with variation determined by the regulator quality and the upstream compressor's cycling behaviour. In precision applications, that difference shows up in the process result.
The EP-CMW4.5-1.2 produces 360 L/min of certified oil-free air at up to 1.2 MPa from a 4.5 kW (6 HP) permanent magnet scroll drive. At 52 +/- 3 dB(A) and 720 x 680 x 1050 mm (150 kg), it is the mid-volume entry point in the world's first 1.2 MPa oil-free scroll compressor range -- providing 71% more air volume than the 3 kW EP-CMW3.0-1.2 while maintaining identical working pressure and the same 2-year air-end warranty. Review the complete EP-CMW 1.2 MPa product range to compare volume options.
How 1.2 MPa Pressure Consistency Affects Process Results
The process quality argument for a native 1.2 MPa source differs by application. In each case, the relevant variable is not the average pressure delivered -- it is the pressure consistency maintained throughout the process event.
Precision Spray Coating
Atomisation in spray coating is a function of air pressure, fluid viscosity, and nozzle geometry. At a given nozzle and fluid combination, a 0.1 MPa variation in supply pressure changes droplet size by a measurable percentage. For automotive refinish, aerospace primer, and fine ceramics glazing, droplet size variation produces surface texture variation that requires additional sanding, clear coat, or rejection. A native 1.2 MPa scroll source with scroll technology's inherently pulse-free output maintains the atomisation condition throughout the spray event.
High-Pressure Calibration and Testing
Pressure instrument calibration requires a reference source stable enough that the uncertainty contribution from the reference source is smaller than the instrument's rated accuracy. At 1.2 MPa, a reference source with +/- 0.05 MPa variation contributes 4.2% uncertainty at the measurement point -- more than the accuracy tolerance of many precision pressure transmitters. A source with less than 0.01 MPa variation reduces this contribution to under 0.9%. Scroll compression's continuous, pulse-free output at 1.2 MPa enables the lower uncertainty figure.
High-Pressure Pneumatic Actuation
Pneumatic actuators and cylinders operating at 1.2 MPa produce output force and speed proportional to supply pressure. In assembly operations where consistent clamping force or insertion depth is required, supply pressure variation directly causes force variation. A native 1.2 MPa continuous source maintains the actuation condition throughout the cycle, rather than varying across the regulator's hysteresis band.
The 4.5 kW Scroll Drive at 1.2 MPa: Engineering Detail
Increasing output from 210 L/min (EP-CMW3.0-1.2) to 360 L/min at the same 1.2 MPa working pressure requires a larger orbital velocity from the scroll mechanism -- the orbiting scroll must trace its path faster to generate more compression events per minute. The 4.5 kW permanent magnet motor provides the additional drive torque needed to sustain this higher orbital velocity against the 1.2 MPa discharge pressure without mechanical stress concentration at the eccentric drive bearing.
The high-stiffness square air-end housing -- the same design developed to achieve the world-first 1.2 MPa boundary -- is critical at this higher drive speed as well as at the higher pressure. At 4.5 kW drive input, the dynamic bending forces on the scroll assembly during each orbit cycle are larger than at 3 kW. The housing stiffness that resists pressure-induced deflection at 1.2 MPa static pressure also resists the dynamic forces at higher drive speed, maintaining the scroll geometry tolerances that tip seal integrity depends on. This is why the 2-year warranty applies at the 4.5 kW drive rating as well as at 3 kW -- the housing design was validated for both.
The independent cooling fan is sized for the thermal load at 4.5 kW input and 1.2 MPa discharge pressure -- a higher thermal load than in the 3 kW model. The discharge temperature management that enables continuous-duty operation at 1.2 MPa in the smaller unit scales appropriately for the higher drive power, maintaining tip seal operating temperatures within the specified range across the 360 L/min output level.
Specifications and Key Capabilities
360 L/min at 1.2 MPa -- Native High-Pressure Volume
360 L/min of oil-free air delivered at the rated 1.2 MPa working pressure -- not a reduced-pressure figure inflated to look larger. This volume supports two to three simultaneous high-pressure spray guns, multiple calibration stations, or a network of high-pressure pneumatic instruments at sustained continuous-duty output.
52 dB(A) at 1.2 MPa -- Quiet Precision Source
Achieving 52 dB(A) at 1.2 MPa working pressure is a direct result of scroll technology's smooth orbital compression cycle combined with the direct-drive permanent magnet motor. In precision environments where noise affects measurement conditions or operator communication, this acoustic profile is operationally significant.
4.5 kW Permanent Magnet Motor -- 1.2 MPa Torque Profile
The 4.5 kW PM motor with IP65 protection and F-class insulation delivers the specific torque curve needed at 1.2 MPa compression ratio, maintaining scroll orbital speed and volumetric efficiency at the rated output. Motor efficiency exceeds 94% throughout the operating range.
Pulse-Free 1.2 MPa Output -- Precision Instrument Compatible
Scroll compression produces inherently continuous, pulse-free output at any working pressure. At 1.2 MPa, this characteristic is more important than at lower pressures because the amplitude of any pulsation scales with working pressure. Scroll technology's absence of pulsation at 1.2 MPa enables applications where reciprocating sources at this pressure would cause measurement or process interference.
2-Year Air-End Warranty at 1.2 MPa -- Validated Design
The 2-year air-end warranty at full 1.2 MPa working pressure reflects the validation testing programme conducted at this pressure tier -- more extensive than at lower pressures because 1.2 MPa represented a new engineering boundary for scroll technology.
Stainless Steel Air Path -- 1.2 MPa Rated
All air-contact surfaces, including the stainless steel outlet connection, are rated for 1.2 MPa working pressure. Downstream equipment must also be rated for 1.2 MPa -- standard 0.8 MPa or 1.0 MPa rated components are not suitable for use at this pressure without formal de-rating.
Technical Specifications
| Parameter | Specification |
|---|---|
| Model | EP-CMW4.5-1.2 |
| Series Distinction | Part of world's first 1.2 MPa oil-free scroll compressor range |
| Motor Power | 4.5 kW / 6 HP |
| Working Pressure Range | 0.2 - 1.2 MPa |
| Free Air Delivery (FAD) | 360 L/min (at rated 1.2 MPa) |
| Noise Level | 52 +/- 3 dB(A) |
| Outlet Connection | 1/2 inch stainless steel (1.2 MPa rated) |
| Weight | 150 kg |
| Dimensions L x W x H | 720 x 680 x 1050 mm |
| Air-End Warranty | 2 Years (at full 1.2 MPa working pressure) |
| Motor Type | Permanent Magnet, IP65, F-class insulation, >94% efficiency |
| Drive | Direct Drive -- no belt, no coupling |
| Housing Design | High-stiffness square air-end (1.2 MPa rated, world-first design) |
| Cooling | Independent cooling fan -- sized for 4.5 kW / 1.2 MPa thermal load |
| Air-Contact Surfaces | Stainless Steel, 1.2 MPa rated throughout |
| Inlet Filtration | 1 micron |
| PLC Controller | Discharge temperature, pressure, run hours, maintenance reminder, fault alarm |
| Lubrication | Oil-Free -- annual bearing grease only |
Process Outcomes in Practice: Three Applications
France -- Automotive Refinish Colour Matching Centre
Eliminating Colour Variation Between Spray Passes at 1.2 MPa
A French automotive refinish colour matching laboratory using high-end HVLP spray equipment was experiencing subtle colour variation between passes on large panel repairs -- a quality issue that required additional sanding and re-spraying to resolve. Their spray gun manufacturer's technical representative identified the root cause as pressure variation from their regulated-down 1.6 MPa reciprocating compressor, which was causing atomisation inconsistency across the spray event. The EP-CMW4.5-1.2 provided a native 1.2 MPa pulse-free source without regulation. Within two weeks of installation, the laboratory reported elimination of the between-pass colour variation, a 40% reduction in rework time on large panel repairs, and measurably improved first-pass colour match scores on their spectrophotometer evaluation protocol.
★★★★★
"Between-pass colour variation eliminated. 40% less rework on large panels. The spectrophotometer scores confirmed what we could already see." -- Laboratory Technical Director
South Korea -- Precision Pressure Instrument Testing Facility
Reducing Calibration Uncertainty at 1.2 MPa Reference Pressure
A Korean metrology laboratory calibrating high-range industrial pressure transmitters to IEC 60770-1 accuracy classes was unable to certify instruments to Class 0.1 accuracy at ranges above 1.0 MPa because their reference source's pressure variation contributed too much uncertainty at the measurement point. Their previous boosted reference source added +/- 0.08 MPa variation. The EP-CMW4.5-1.2 reduced reference source variation to below 0.015 MPa due to scroll technology's continuous pulse-free output at 1.2 MPa. The laboratory was subsequently able to extend its calibration scope to Class 0.1 instruments at 1.0-1.2 MPa range, opening a new calibration service category that had previously been outside their technical capability.
★★★★★
"Reference source variation from 0.08 MPa down to 0.015 MPa. We can now certify Class 0.1 instruments at 1.2 MPa range -- a new calibration scope we couldn't offer before." -- Chief Metrologist
Australia -- Industrial Ceramics Manufacturer
Consistent Glaze Atomisation Across Extended Production Runs
An Australian manufacturer of high-specification industrial ceramics applying oxide glaze coatings required 360 L/min at 1.2 MPa to supply their four glazing guns at the atomisation pressure specified for their target particle size distribution. Their previous solution -- a 1.6 MPa oil-injected compressor regulated to 1.2 MPa with coalescence filtration -- produced two recurring problems: oil contamination events that caused glaze pinholing, and pressure variation across long production runs as the compressor cycled that changed glaze coverage density. The EP-CMW4.5-1.2 eliminated both. Oil pinholing stopped immediately. Pressure consistency across four-hour production runs improved to the point where their quality team reduced sampling frequency from every 30 minutes to every 90 minutes, saving approximately 15% of quality inspection time per shift.
★★★★★
"Oil pinholing gone, pressure consistent across full production runs, and our quality sampling frequency halved. The precision argument for 1.2 MPa oil-free was absolutely correct in our case." -- Production Quality Manager
Frequently Asked Questions -- EP-CMW4.5-1.2
Is the process quality difference between a native 1.2 MPa source and a regulated-down source measurable?
In precision applications, yes. The difference is not relevant for standard industrial pneumatic tools where pressure variation across a regulator's hysteresis band has no process consequence. For precision spray coating, high-accuracy pressure calibration, and sensitive analytical instruments, the contribution of regulator variation and upstream compressor cycling to measurement uncertainty or surface quality is quantifiable -- as the case studies on this page illustrate.
Is the 360 L/min FAD measured at 1.2 MPa or at atmospheric conditions?
The 360 L/min free air delivery is measured at the rated maximum working pressure of 1.2 MPa. This is the actual output available at full working pressure -- not an atmospheric or partial-pressure figure. At lower working pressures within the 0.2-1.2 MPa range, volumetric output will be somewhat higher due to the reduced compression ratio.
Does all downstream equipment need to be rated for 1.2 MPa?
Yes -- all downstream equipment must be rated for 1.2 MPa working pressure. This includes inline filters, dryers, pressure vessels, flexible hoses, fittings, gauges, and any instrumentation in the compressed air circuit. Standard 0.8 MPa or 1.0 MPa rated equipment should not be used at 1.2 MPa without formal engineering review. This is a safety requirement, not a performance preference.
How does scroll compression maintain pulse-free output at 1.2 MPa specifically?
Scroll compression is inherently continuous because multiple compression pockets are always in different stages of the cycle simultaneously. At any instant, one pocket is near intake volume, one near mid-compression, and one near discharge -- so air flows continuously to the outlet regardless of working pressure. This is a physical characteristic of the compression mechanism, not a feature added at low pressures and removed at high pressures.
What is the annual maintenance requirement at 1.2 MPa working pressure?
Annual maintenance is identical to lower-pressure CMW models: bearing grease addition once per year, inlet filter element replacement at the PLC-indicated interval, and tip seal ring inspection and replacement based on accumulated PLC-logged operating hours. The tip seal and scroll surface specifications for the 1.2 MPa model are designed for these standard service intervals at full working pressure. There is no oil change, no separator element, and no water-oil management.
Selecting the EP-CMW4.5-1.2 for Your Precision Process
The EP-CMW4.5-1.2 is the answer when the process specification genuinely requires 1.2 MPa oil-free air at mid-volume output, and when the quality difference between a native 1.2 MPa source and a regulated-down alternative is a process engineering question rather than a preference. If your application is in that category, the engineering case for this unit is straightforward.
Ever Power's application team can assist with process pressure analysis, downstream equipment specification at 1.2 MPa, and validation documentation for regulated applications. Learn more about Ever Power's engineering and manufacturing background, or review all models in the complete EP-CMW 1.2 MPa product range.
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