A modern compressor with a PM motor is the ideal solution for businesses that regularly use compressed air and wish to better control the operating costs of their pneumatic systems. A PM motor, or permanent magnet motor, is characterised by high efficiency, smooth operation and the ability to regulate speed continuously when used in conjunction with an inverter.
For whom is a compressor with a PM motor the best choice?
A modern compressor with a PM motor is the ideal solution for businesses that regularly use compressed air and wish to better control the operating costs of their pneumatic system. A PM motor, or permanent magnet motor, is characterised by high efficiency, smooth operation and the ability to continuously vary its speed when used in conjunction with a variable frequency drive.
This technology is most beneficial where air demand is not perfectly constant. The compressor can then adjust its output to match current consumption, maintain a stable operating pressure and limit operation within an unfavourable range. However, the ultimate savings depend not only on the motor itself, but also on the choice of compressor, the system’s airtightness, the operating pressure, the quality of dehumidification and the actual air consumption profile.
What is a PM motor in a compressor?
A PM motor is an electric motor that uses permanent magnets. Compared to conventional induction motors, it can achieve high efficiency across a wide operating range, particularly when used in conjunction with an inverter. In practice, this means that the rotational speed can be better matched to the system’s current demand.
In a screw compressor, the motor drives the compression stage. As air demand increases, the system can increase the speed, and as demand falls, it can reduce output. As a result, the unit does not have to operate continuously in a single, fixed mode, which often does not correspond to the actual conditions at the site.
It is worth bearing in mind that the mere presence of a PM motor does not automatically guarantee the lowest costs. The key factors are: correct capacity selection, appropriate operating pressure, a well-designed system, minimising leaks and regular servicing.
When is it worth choosing a compressor with a PM motor?
A compressor with a PM motor is particularly suitable when compressed air consumption varies throughout the day. In many companies, the air-consuming equipment does not operate constantly at the same load. At times, several pneumatic tools are in use; at other times, the system supplies only a single workstation or operates in standby mode.
In such a scenario, a variable-speed compressor can supply air more flexibly. Instead of frequently switching between operating under load and idling, the unit can respond more smoothly to demand. This helps to reduce energy losses and maintain a more stable pressure in the system.
The greatest benefits are usually seen during regular operation: in single-shift, two-shift or three-shift operations, in manufacturing plants, service centres, paint shops, workshops and companies that cannot afford frequent drops in pressure.
For which businesses is a PM compressor the best choice?
A compressor with a PM motor will be a good choice for companies that regard compressed air as a vital technological medium, rather than merely an auxiliary power source. The more frequently the compressor operates and the more variable the air demand is, the greater the importance of drive efficiency and capacity control.
- Manufacturing plants – where compressed air powers production lines, machinery, actuators, valves and assembly stations.
- Car workshops – for pneumatic wrenches, inflation, blowing out and servicing.
- Paint shops – where stable pressure and appropriate air quality following filtration and drying are essential.
- Metalworking workshops – for powering tools, blowing out, pneumatic clamping and auxiliary equipment.
- Joinery firms – for pneumatic tools, workstation cleaning and air-powered machinery.
- Maintenance departments – where reliability, rapid air availability and stable performance are essential.
Workshops, service centres and manufacturing – practical applications
In workshops and service centres, the PM compressor can power impact wrenches, paint spray guns, pneumatic grinders, blowers, pumps, tyre inflators and other consumers. Under such conditions, air consumption is often irregular: short bursts of intensive tool use alternate with periods of inactivity.
In manufacturing, however, process continuity is key. If several workstations are using air simultaneously, a drop in pressure can affect the pace of work, the quality of operations and operator comfort. A well-chosen compressor helps to maintain more predictable conditions and reduce the risk of interruptions caused by a shortage of air.
It is worth bearing in mind, however, that a compressor will not solve the problems caused by a poorly installed system. Pipe diameters that are too small, leaks, incorrect filtration or poorly selected dehumidification can limit the effectiveness of even the best compressor.
Oil-lubricated, oil-free or PM compressor?
When selecting a compressor, two aspects must be distinguished: the type of drive and the type of compressor design. The term ‘PM’ refers to the drive, whilst the terms ‘oil-lubricated’ and ‘oil-free’ relate to the operating principle of the compression stage and the air quality requirements.
Oiled compressors are often chosen for workshop and industrial applications where durability, efficiency and the ability to operate intensively are important. Oil-free models are used where a high level of air purity is required, for example in certain painting, food processing, medical or laboratory processes – in accordance with the requirements of the specific installation.
A PM motor can form part of a modern compressor system, but it does not replace filtration, a dryer or separators. If a process requires a specific class of air purity, the entire air treatment system must be selected, not just the compressor itself.
What should you look out for before buying?
The selection of a compressor with a PM motor should begin with an analysis of the compressed air demand. The most important parameter is not the motor power itself, but the effective capacity at the required operating pressure.
- Effective capacity – this should correspond to the actual air consumption by the end-use equipment.
- Operating pressure – excessively high pressure increases energy costs and the load on the system.
- Tank capacity – affects operational stability and the air reserve during temporary consumption peaks.
- Operating profile – one compressor will be suitable for intermittent operation, whilst another will be better suited to long periods of continuous operation.
- Air quality – filtration and drying must be tailored to the tools and the process.
- Pneumatic system – pipe diameters, leak-tightness and the layout of air outlets all affect pressure stability.
- Service and spare parts – the availability of technical support is important in the case of intensive use.
When is a PM motor not necessarily required?
A compressor with a PM motor will not always be the only sensible choice. If the compressor is to be used sporadically, for short periods and with low demand, a simpler model may suffice. This applies, for example, to occasional inflation, short-term hobby projects or workstations where air is used infrequently.
PM technology really comes into its own with regular use and variable loads. If the compressor runs for many hours a day, energy costs start to make a significant difference. In such cases, it is worth analysing not only the purchase price but also the total cost of ownership.
PM compressor – where does it perform best?
| Applications | Is it worth considering a PM compressor? | Why? |
|---|---|---|
| Multi-station production | Yes | Variable air intake, a need for stable pressure and continuous operation |
| Car repair workshop | Yes, with regular use | Short consumption peaks, pneumatic tools, need for rapid system response |
| Paint shop | Yes, with appropriate air treatment | Stable pressure and air quality affect the quality of the work |
| Occasional use | Not necessarily | For short periods of operation, energy savings may be less significant |
| Processes requiring high air purity | Yes, but it is not just the motor that is important | Filtration, dehumidification and the selection of a compressor suited to the required air quality class are essential |
FAQ – frequently asked questions
Does a compressor with a PM motor always consume less energy?
It may consume less energy, particularly with variable demand and when used with a variable frequency drive. However, the actual result depends on the choice of equipment, operating pressure, the tightness of the system and how it is used.
Is a PM motor suitable for continuous operation?
Modern screw compressors with PM motors are designed for intensive operation, but you should always check the specifications of the specific model, the manufacturer’s recommendations and the operating conditions.
Does a PM compressor replace a dehumidifier?
No. The PM motor drives the compressor. If the system requires dry or very clean air, a suitably selected dehumidifier, filters and separators are required.
Is it worth choosing a PM compressor for a small workshop?
Yes, if the workshop regularly uses pneumatic tools and requires stable pressure and lower running costs. For very occasional use, a simpler compressor may be sufficient.
Summary
A PM motor-driven compressor is the best choice for businesses that regularly use compressed air, operate under varying loads and wish to reduce energy costs. This solution is ideal for manufacturing plants, garages, service centres, paint shops and industrial companies where stable pressure, efficiency and predictable system operation are essential.
Before purchasing, it is worth analysing the effective capacity, required pressure, operating profile, air quality and the condition of the pneumatic system. CORMAK’s range includes compressors tailored to the needs of workshops, manufacturing and industrial applications where energy-efficient and stable operation is essential.
