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Frequency converters enable energy savings and sensorless operation monitoring in pump and fan systems. This is possible with model-based estimation methods that apply frequency converter estimates of the rotational speed and the shaft power. Since compressors produce air flow similarly as fans, the same estimation methods should be applicable, if the fluid density change can be detected and analyzed...
Pump, compressor and fan systems often have a notable energy savings potential, which can be identified by monitoring their operation for instance by a frequency converter and model-based estimation methods. In such cases, sensorless determination of the system operating state relies on the accurate estimation of the motor rotational speed and shaft torque, which is commonly available in vector- and...
A wrong rotational direction of a centrifugal device is detrimental for the service life and energy efficiency of the device. However, in some cases, visual inspection of the correct rotational direction is difficult or even impossible. This paper presents a sensorless method that can detect the correct rotational direction of a centrifugal device. The method is verified by laboratory tests for a...
Energy consumption in pumping systems is affected by the surrounding process. As frequency converters allow sensorless estimation of the pump operating state, they can also be used for the process characteristics identification. In this paper, two frequency-converter-based methods to identify process characteristics are proposed, and the start-up test method is more closely studied by laboratory tests.
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