Why torsional vibration in variable speed drive systems deserves an attention? Introduction I am an electrical engineer, same as probably most of the readers of our blog. The electro-mechanical interaction within the drive system is therefore not so easy to Read more…
Neutral point treatment of a converter transformer A common question of system integrators or end users is about the neutral point treatment of a converter transformer. Can or shall the neutral point be earthed? What are the consequences for the Read more…
VFD protection reaction Reliable protection is key for long term successful operation of a variable frequency drive (VFD). There is a wide range of situations outside of the normal operation to what the drive system shall respond. In this blog Read more…
VFD Soft Starters – Methods of Synchronous Transfer Abstract Purpose of a VFD soft starter is to start and accelerate the motor up to the nominal speed. The final step is to synchronize the machine with the grid and transfer Read more…
Most common medium voltage VFD topologies in comparison Abstract Medium voltage drives consist of several topologies. While some of them are seldom found in industrial applications, others are very popular and create integral part of the portfolio of most global Read more…
What is the definition of short-circuit impedance? Short-circuit impedance, also called impedance voltage, is an important design parameter of a transformer [1]. Thus, it is crucial to understand this parameter. In this brief post we introduce three ways of definition Read more…
Black Friday Sale MB Drive Services participate in the biggest savings event of the year! The traditional Black Friday sale is combined with a 6 years anniversary of our first blog post that started the whole journey. This Black Friday, Read more…
Considerations about motor noise level This post provides few considerations about motor noise level with respect to inverter supply. Noise might be considered as one performance criteria of the motor. Noise level of electric equipment is regulated by standards and Read more…
Comparison of air core and iron core choke There are various reasons for installation a choke¹ within a variable frequency drive system – see [1] for an overview. The next question is about the design of such choke. This post Read more…
VFD compliance with voltage and current harmonic limits National and international standards provide guidelines and limits for individual harmonics and total harmonic distortion. But how to assess the situation when the VFD meets the limits for voltage harmonics while current Read more…