Permanent Magnetic VSD Screw air compressor EPM series

EPM Screw Air Compressors with Permanent Magnet Motors

The EPM series screw air compressors combine permanent magnet motors with variable speed control. The system changes motor speed according to actual compressed air demand instead of operating continuously at maximum output.

This solution is suitable for industrial facilities where demand changes throughout the working day. When fewer machines are operating, the compressor can reduce its air output. As demand increases, the control system raises motor speed within the operating range of the selected model.
A correctly sized variable speed screw air compressor can reduce unloaded operation and limit sudden pressure fluctuations. Actual efficiency also depends on the condition of the air distribution network, pressure settings and the level of air leakage.

Models from 15 to 45 kW

The EPM series includes six main power ratings:

• SCR20EPM – 15 kW;
• SCR25EPM – 18.5 kW;
• SCR30EPM – 22 kW;
• SCR40EPM – 30 kW;
• SCR50EPM – 37 kW;
• SCR60EPM – 45 kW.

The SCR20EPM and SCR25EPM models are suitable for smaller production areas, individual CNC machines and groups of pneumatic consumers. The SCR30EPM and SCR40EPM can supply larger working areas and production lines, while the SCR50EPM and SCR60EPM are intended for installations with higher and more continuous compressed air demand.

Motor power alone is not sufficient for correct selection. Air delivery at the required working pressure, operating profile and maximum simultaneous consumption must also be considered.

Free Air Delivery from 0.58 to 9.5 m³/min

The overall free air delivery range of the EPM series is 0.58 to 9.5 m³/min. Actual values depend on the selected power rating and working pressure.

The 15 kW SCR20EPM provides up to 3.0 m³/min at 7 bar. The 30 kW SCR40EPM delivers up to 6.2 m³/min, while the 45 kW SCR60EPM reaches up to 9.5 m³/min at 7 bar.

Maximum air delivery generally decreases as working pressure increases. For example, the SCR60EPM provides up to 9.5 m³/min at 7 bar, 9.4 m³/min at 8 bar and 8.0 m³/min at 10 bar.

The compressor should therefore be selected according to the required combination of air delivery and pressure rather than only the highest value shown in the technical table.

Working Pressure of 7, 8 or 10 Bar

All EPM models are available in configurations for 7, 8 and 10 bar. This range is suitable for many standard industrial pneumatic systems, but the selected version must match the requirements of the connected equipment.
The lowest pressure at which the machines and tools can operate reliably should normally be selected. Pressure losses through pipelines, filters, dryers and other system components must also be considered.

Selecting unnecessarily high pressure can increase energy consumption and reduce the available air delivery.

Advantages of Variable Speed Control

VSD control allows compressor output to follow current air consumption. This is particularly useful when pneumatic consumers do not operate simultaneously or when demand changes frequently.

The main advantages include:

• smooth motor speed regulation;
• adjustment to fluctuating air demand;
• more stable system pressure;
• reduced unloaded operation;
• fewer frequent load and unload cycles;
• smoother motor starting.

Variable speed control should not be considered a substitute for correct compressor sizing. An excessively large or undersized compressor will not operate optimally regardless of its control system.

Applications of EPM Screw Air Compressors

EPM compressors can be used in various industrial and technological processes, including:

• CNC machining equipment;
• metalworking machines;
• automated production lines;
• pneumatic tools;
• assembly and packaging machines;
• industrial workshops;
• pneumatic automation;
• central compressed air installations.

For applications with specific air quality requirements, the system should include a suitable dryer, line filters, an air receiver and condensate drainage equipment.

How to Select the Correct EPM Compressor

Determine Average and Peak Air Demand
Calculate the total air delivery required by all consumers that may operate simultaneously. Short-term peaks should be considered in addition to average consumption.

Match Air Delivery to Working Pressure
The air delivery of the same model differs at 7, 8 and 10 bar. Compare the technical values at the pressure required by your equipment.

Allow a Reasonable Capacity Reserve
A moderate reserve can support future expansion and temporary consumption peaks. Excessive oversizing, however, may result in inefficient operation at low load.

Check Installation Conditions
Consider the compressor dimensions, weight, room ventilation, ambient temperature, service access and the connection size of the compressed air system.

Consultation for Screw Air Compressor Selection
Accurate compressor selection requires information about working pressure, average and maximum air consumption, operating hours and the number of consumers operating simultaneously.

Contact our team for technical consultation and assistance in selecting an EPM series screw air compressor according to the requirements of your compressed air system.

Frequently Asked Questions

What is the power range of the EPM series?

The series includes models from 15 to 45 kW, corresponding approximately to 20–60 HP.

What is the maximum free air delivery?

The maximum stated free air delivery is 9.5 m³/min for the SCR60EPM model at 7 bar.

Are models available for pressures above 10 bar?

No. The listed EPM models are available for 7, 8 and 10 bar working pressure.

Is an EPM compressor suitable for fluctuating demand?

Yes. Variable speed control regulates motor speed according to current compressed air demand.

What is the difference between air delivery at 7 and 10 bar?

Maximum air delivery is generally lower at higher pressure. The exact values vary between models.

Is an air receiver required?

In many systems, an air receiver helps stabilise pressure and cover short-term demand peaks. Its required volume depends on compressor output and the operating profile.