What is the right strategy to retrofit fix-speed motor into VFD operation? As addressed in our previous post, a retrofit of a direct on-line (DOL) machine into VFD duty may be a very attractive choice [1]. This post focuses a bit on the practical aspects. What do I need to Read more…
Purpose of electrostatic shield What is the electrostatic shield and why is it actually used? This article briefly explains the purpose of electrostatic shield in VFD input transformers [1]. First note that there are several terms being used for what we called “electrostatic shield” in the title of this article: Read more…
Benefits of transformer rental service Transformer rental aims to maximize the availability of drive system and reduce the cost impact as much as possible. In this post we will briefly describe the benefits of transformer rental service. Reliability of transformers Transformers belong to some of the most reliable electric equipment. Read more…
Torque meter in variable speed drive systems Unlike electrical quantities the measurement of torque is not an easy task. Hence in most cases the torque is not measured directly but calculated (estimated) from electrical signals. But what if you need high absolute accuracy of torque control? In such case a Read more…
Traction converters Traction power electronic converters play a key role in modern transportation. Unlike industrial converters they face slightly different and specific challenges with regards to design, operation mode or safety.In this post we provide a brief look into the power electronics that we usein everyday’s life when using traditional Read more…
4 common defects of liquid immersed transformers In this post we present some of the common defects appearing in liquid immersed transformers. As stated at the end of this article always adhere to all applicable safety rules and regulations. Leaks of insulating liquid Despite high quality standards and best practices Read more…
Retrofits of DOL motors: Low-hanging fruit? Despite clear benefits of VFDs in motor drives, most industrial motors are still of fix-speed type. This is true for newly manufactured motors and even more for the installed base. Hence there is a huge potential for retrofits of fix-speed direct on-line (DOL) motors. Read more…