Jussi Tamminen

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Modern frequency converters allow energy efficient operation of induction-motor-driven systems such as pumps and fans. In addition, they can be used as a sensorless monitoring unit for the pump and fan systems, as shown by previous studies. Sensorless diagnostics of induction-motor-driven systems relies on the accurate estimation of the rotational speed,(More)
While the cause-and-effect chains of inverter-induced bearing currents have been well understood today, not much is known about the damage mechanism inside the bearings. Research has suggested that the bearing degradation is approximately proportional to the frequency of occurrence of the bearing currents. For bearing currents that occur statistically(More)
Pumps are widely used in industrial applications, and they account for nearly a quarter of the electric energy consumption in the European industry. Pumps are often overdimensioned or they may be driven inefficiently, which causes unnecessary energy costs. If the pump drive is not equipped with appropriate measurements, inefficient pump operation may remain(More)
Energy harvesting or scavenging from environment is being researched intensively. The main motivation of the research is to develop a maintenance free energy source for ubiquitous electronics, such as wireless sensors or sensor networks. The on-line condition monitoring of electric motors requires also sensors that are installed at the motor. In this case,(More)
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(More)
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,(More)
Often, the components of a pumping system are not selected from the perspective of the total system, as the individual components are selected using different programs. In this paper, a selection tool that optimizes the energy conversion efficiency of a pumping system according to actual process requirements is introduced. The tool requires only the catalog(More)
In previous publications [1]-[3] it has been demonstrated that the power line communication (PLC) is a feasible method for data transmission between a LV (Low Voltage) motor and a frequency converter. In this paper, attenuation and noise power spectrum of the motor cable communication channel are analyzed. The analysis is based on a laboratory test setup,(More)