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1 Maszyny Elektryczne : zeszyty problemowe
1 Prace Naukowe Instytutu Maszyn, Napędów i Pomiarów Elektrycznych Politechniki Wrocławskiej. Studia i Materiały
1 Scientific Papers of The Institute of Electrical Machines, Drives and Measurements of the Wrocław University of Science and Technology Series: Studies and Research
1 Wiadomości Elektrotechniczne

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Napięcia wałowe i prądy łożyskowe

Chmelik K., Čech V.

Maszyny Elektryczne : zeszyty problemowe

2002

Nr 64

37-39

The problem of shaft voltage origination in electrical machines was known and studied already at the beginning of the past century. The shaft voltage can occur also by synchronous generator with exciting winding fed from static exciter. When we will not respect any specific designing and mounting principles it can happen to current flow through bearings. Conductive path is created by closed circuit compounded from motor frame, bearing shields, bearings and shaft. In the other cases it can be concerned a circuit consisted from winding, air gap, bearing, capacitance or possible capacitance of other parts against ground. Different parts of bearings can be damaged by these currents and so it comes to operation state deterioration. In our paper we want to show measuring results of small and large power motors.

Electric machines older construction fed from frequency converters

Chmelik K., Čech V.

Prace Naukowe Instytutu Maszyn, Napędów i Pomiarów Elektrycznych Politechniki Wrocławskiej. Studia i Materiały

2000

Vol. 48, nr 20

230-236

The working life of electrical machines of great power (over 1MW) averages generally several decades. By the reconstruction of production aggregates due to saving of power in industrial or power enterprises and societies, the reconstruction of drive is often required but only with the existing electric motor. It goes for example about feeding of DC motor from rectifiers, use of slip-ring induction motor in subsynchronous cascade, feeding of asynchronous or synchronous motor from frequency converter with current or voltage intermediate circuit. Keeping of the same or slightly increased rated output and torque is supposed. The presentation of project, realization and practical operation experiences of such reconstructed drives in great enterprises should be the subject of this paper. Saving of power, EMC problems etc. will be presented.

Silnik indukcyjny klatkowy zasilany napięciem niesinusoidalnym

Chmelík K., Čech V.

Wiadomości Elektrotechniczne

1998

nr 4

210-216

Przedstawiono zagadnienia przepięć generowanych w układzie napędowym składającym się z falownika MSI,kabla zasilającego i silnika indukcyjnego klatkowego. Przedstawiono przebiegi czasowe wzbudzanych impulsów napięciowych. Wykazano, że na te przepięcia jest narażona głównie izolacja zwojowa cewki początkowej uzwojenia.

This article deals with problems of overvoltages generated in a drive system consisting of an inverter,a feeding cable and an induction cage motor. Timedependent waveforms of the excited voltage pulses are presended. It has been proved that exposed to the overvoltages is mainly the turn-to-turn insulation of the first coil of the motor winding.