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 chokeĀ¹ 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
When to go for an active front end drive? Abstract Grid side of the VFD can be either Diode Front End (DFE) or Active Front End (AFE). The later one is more expensive but brings several additional options such as Read more