VFD transformers and harmonics Introduction The next post in our series discusses VFD transformers and harmonics. We have already learned what harmonics are and how they impact the supply grid (Network harmonics – intro). In this series we look more specifically into harmonics and their impact on VFD transformer. Motivation Read more…
VFD transformers: Multi-winding design Today we look at the design of multi-winding VFD transformer feeding variable frequency drives. These VFD transformers are often classified in the category of ‘special transformers’. What does it mean? Why are they special? If you want to get these answers and a little insight into Read more…
VFD transformers: Introduction After reading this blog post you should understand the purpose of a VFD transformer and the differences between distribution/power transformer and a VFD transformer. Let’s start with the definition of a VFD transformer: This term refers to the input isolation transformer that supplies the rectifier section of Read more…
Literature on Variable Frequency Drives, Power Electronics and related subjects The purpose of this blog is to provide useful information about Variable frequency drives (VFD) and power drive systems that you might appreciate when working in this field (specifying, selecting, purchasing, operating, servicing/retrofitting, researching or developing tasks). The blog intentionally Read more…
Network harmonics:Introduction Apart from the numerous advantages of variable frequency drives, such as precise speed or torque control, smooth motor starting or energy savings, this technology also comes with specific challenges. One of them are the network harmonics. The good news is that there is a solution. Actually, there are Read more…
VFD versus fluid coupling Today we open a topic that might polarize our readers: Comparison between variable frequency drive (VFD) and a fluid (hydrodynamic) coupling. Of course, this blog is dedicated to VFDs. Nevertheless, we intend to provide an objective benchmark as far as possible. Please note that there is Read more…
Encoders in motor drive applications What is the purpose of encoder? When is it needed? What types of encoders are being used? This post shall answer some of these questions. VFDs are used to control the motor speed or motor torque. The actual speed is either estimated (speed sensorless control), Read more…
Solutions for variable speed control: Introduction This post introduces the most common solutions for variable speed control in industrial applications. Before starting with the topic we want to refresh the meaning of some commonly used abbreviations. Variable speed drive (VSD) – A general term for anything that varies the speed Read more…
LCI versus VSI:Part 3: Comparison Figure 1: LCI vs VSI In today’s column we continue our popular series ‘LCI vs VSI’ and look a bit closer at the differences between a load-commutated inverter (LCI) and voltage source inverter (VSI). 1. History and references The history of LCI started in mid Read more…
Project specificationsToo little / too much? In this post we talk about balancing the length and especially the content of project specifications. What is too little and what is too much? How to specify your requirements? Let us spend some thoughts on this subject. Balancing the project specifications Specifications are Read more…