Compressed air is generated by converting electrical energy into compressed air. Modern air compressors convert 80 – 90% of this energy into heat and only 10 – 20% into compressed air, making compressed air up to ten times more expensive than electrical energy. Only if they know what electrical power is being consumed to generate the compressed air can operators of the compressed air system monitor and optimize the system.

SUTO Power meters, energy meters and current sensors are compact, easy to install and provide accurate power measurements, whereby users can change their Operating costs for compressed air can lower.


Measuring the electrical power consumption of a compressor is the first step to understand the compressed air system. Compressed air is produced by electrical energy, so the costs of the electrical energy are the indirect costs of the compressed air. But many compressed air operators do not know how much electrical energy their compressors are using and how much the compressed air costs.

By this, the operating costs of the compressed air system just fall under the general electrical bill, not noticing that the compressed air might be the biggest consumer of electrical energy in the factory. Only a power or energy meter can help to understand the compressed air system’s energy consumption.

What is an energy meter and what are the benefits?
A power meter, or energy meter, is a measurement device, which is able to measure the voltage and the current of an electrical consumer, for example a compressor. By measuring these values, the power meter is able to calculate the power consumption of the consumer. Typically, it outputs the Current, Voltage, Frequency, Active and reactive power, active and reactive energy, power factors and more.

The benefits of a real power meter is, that it actually measures the system’s power consumption, it does not rely on constant assumed factors, but really measures the electrical characteristics. By this, it offers a reliable and true power measurement.

Why are power meters used in compressed air systems?
Compressed air is an expensive energy form, since it’s produced by compressors, which have a low efficiency factor. Designing a compressed air system is mostly done by summing up all machines on the demand side and adding some safety volume to that. But that means at the same time, the bigger compressor will then use more electrical energy.

In the end, every cubic meter of air will have its specific cost, and every bar of pressure will increase or decrease the compressed air costs. If operators want to know their compressed air costs, they must measure the electrical consumption of the compressors, only by this the efficiency can be monitored and optimized.

Why is it important that a power meter always measures the voltage and current on all phases?
In many installations, measurement providers are measuring only the voltage and current on a single phase. By then assuming power factors, without knowing the actual phase shift, the measurement providers then specify the electrical power consumed by compressors. But this can not be considered as a real power measurement, as assumed factors are taken into place, which is not what operators want to have.

SUTO power and energy meters are always measuring the current and voltage of all phases, only by this the onsite changes, the frequency changes or phase shifts can be considered in the measurement.

How can power meters in compressed air system reduce maintenance costs?
A brand-new compressor will have a defined electrical energy consumption at a certain air flow output. But as a compressor is a machine which wears off, it is likely that at a certain age the compressor will deliver less air flow at the same rate of energy consumption. This means, the electrical costs are the same or even higher, but the air flow output gets less.

By monitoring the electrical energy consumption of the compressor and comparing it with the flow output, users of a compressed air system are able to know when it is time to maintain the compressor. Degrading components can be identified, repaired and possibly safe a lot of operating costs.

How are SUTO current sensors installed on site?
SUTO current sensors are Rogowski current coils. The advantage is, that the Rogowski coils are easily installed by simply clamping them around the cables or wires. This is possible without interrupting the process. The wire will then induce a current into the coil, which is then transformed to an electrical signal.

The advantage compared to typical current transformers is, that the position of the cable inside the coil is not that important, still offering a high grade of accuracy. Besides that, the rogowski current coils are very compact and light-weight, which makes them the prefect equipment used in energy audits.

A portable SUTO solution for power measurements is set up within minutes, just clamping the current coils around the cables and connect the voltage to the power meter.

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