What is the time constant of a dc link? Introduction Most commercially used variable frequency drives (VFD) belong to the category of indirect frequency converters. The AC power of a fix frequency (usually 50 or 60 Hz) is first rectified and then the DC signal is inverted into AC power Read more…
LCI celebrates 50 years anniversary! It is little bit hard to believe but the high-power drive champion LCI celebrates 50 years anniversary in 2024. We take this opportunity to look back at the history of this matador and maybe also a little outlook. Birth of LCI in 1974 It was Read more…
What is the best investment in 2024? Beginning of a new year is linked with new goals, ambitions and expectations. In the economic field many people probably hope that the inflation finally drops, the major economies do not fall into recession, unemployment rate remains low and the purchasing power increases. Read more…
When is transformer tap changer needed? The input isolation transformer in a drive system may be equipped with a tap changer. Such device provides some flexibility but adds cost and potentially also complexity to the transformer design. Thus, the question is whether a tap changer is needed or not. The Read more…
Get our Blog Book in pdf format Do you enjoy reading our blog online? Then you might be interested to get your own copy of all our blog posts in form of a digital blog book. History of our blog We had the idea to write posts about medium voltage Read more…
High-speed drives:Introduction Since a long time we wanted to write more about high-speed drives, their theory, design, application etc. Finally we manage to publish this short post providing an introduction into high-speed drives. In line with our blog, the focus will be on medium voltage and medium/high-power drives. Introduction Variable Read more…
Variable Speed Motors – Which type suits the best? Electric variable speed drive system consists as minimum of a VFD and an electric motor. So the question is: Which motor type suits the best for variable speed control? As usual, the answer depends on multiple factors. Among those factors belong Read more…
What is the difference between VFD and VDS? This article aims to answer one relatively simple question: What is the difference between VFD and VSD? As the question was raised again recently, we would like to deliver an understandable explanation. Let’s start with the abbreviations first to ensure that we Read more…
How to choose a medium voltage VFD:Service network and reaction time From end user’s perspective the uptime of the plant is crucial. The cost of loss of production quickly exceeds the equipment cost of the VFD. Therefore, you need a strong partner to support you with any kind of technical Read more…
VFD switching frequency The heart of every variable frequency drive (VFD) is the power semiconductor. By switching on and off in a proper modulation scheme the frequency conversion functionality is achieved. Let’s look at various aspects of VFD switching frequency. Switching frequency of medium voltage VFDs Having medium voltage VFD Read more…