How are VFD and motor frame sizes defined? When talking about the size of variable frequency drives (VFD) and motors, the word frame is often used. What is the definition of VFD and motor frame size? That is shortly explained in this post. Why using frames? The main reason is Read more
How is the VFD installed in a civil structure? In this post we look at the ways how to install VFD into a civil structure, meaning a building. What options exists and how do they differentiate? 3 ways of VFD installation Variable frequency drive (VFD) typically is an indoor equipment. Read more
How well do you know variable frequency drives and drive systems? Take a short quiz to test your knowledge about variable frequency drives (VFD) and VFD based drive systems. 1. Nominal current of asynchronous motor with pf = 0.88 is 500 A (FLC). How much is the current at 50% Read more
How to size cables in high-power drive systems? Most common power connection in between drive system components is a cable. In this post we look at some factors to consider when sizing cables in high-power medium voltage variable frequency drive (MV VFD) systems. Cable basics Let’s start with some basics 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 VFD manufacturers. In this article we look at the most Read more
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