Electrical Lectures
Basic PLC program for control of a three-phase AC motor (for beginners)
While the lighting control system previously discussed is useful to explain basic PLC operation, a more practical, and only slightly more complex, application is start-stop control of an AC motor. Before examining the PLC program, first consider a hard-wired approach…. Read more
Dec 25, 2015 | By Edvard Csanyi
Electric Motor
Five factors that mess up motor efficiency and how to improve it
It must be emphasised that the standard electric motor is already a very efficient device with efficiencies above 80% over most of the working range, rising to over 90% at full load. However, because of the high energy consumption, and the… Read more
Dec 23, 2015 | By Edvard Csanyi
Energy and Power
The Basics Of Circuit Breaker Tripping Units
The main objective of circuit breaker tripping units and protective functions in general is to detect faults and to selectively isolate faulted parts of the system. It must also permit short clearance times to limit the fault power and the… Read more
Dec 21, 2015 | By Edvard Csanyi
Energy and Power
Learn To Interpret Single Line Diagram (SLD)
We usually depict the electrical distribution system by a graphic representation called a single line diagram (SLD). A single line can show all or part of a system. It is very versatile and comprehensive because it can depict very simple… Read more
Dec 19, 2015 | By Edvard Csanyi
Energy and Power
The good ventilation of switchgear and transformer rooms
In order to design a good ventilation of switchgear and transformer rooms, the air in the room must meet various requirements. The most important is not to exceed the permissible maximum temperature. Limit values for humidity and air quality, e.g…. Read more
Dec 18, 2015 | By Edvard Csanyi
Energy and Power
Distribution of the MV neutral conductor right to the loads
4-wire systems are characterized by distribution of the MV neutral conductor right to the loads. This type of distribution is used in the USA and in certain countries influenced by North America, and is always subject to ANSI regulations. It… Read more
Dec 16, 2015 | By Edvard Csanyi
Energy and Power
The basics of primary medium voltage switchgear
Primary medium voltage switchgear represents an important part within the primary distribution substation functionality. The switchgear works as a connection node between the outgoing distribution feeders and the in-feeding power transformers. The most common construction with the switchgear is an… Read more
Dec 14, 2015 | By Edvard Csanyi
Metering
Protective relay – The brain that detects abnormal system conditions
For medium voltage circuit breaker applications, protective relay serve as the “brain” that detects abnormal system conditions and direct the circuit breaker to operate. They also serve to provide specialized protection in low voltage power circuit breaker applications for functions… Read more
Dec 12, 2015 | By Edvard Csanyi
Energy and Power
Real time reactive compensation – A case with 5 problems and solutions
A car equipment manufacturer’s plant in Concord (Ontario, Canada) is supplied by a transformer rated at 2000 kVA – 27.6 kV / 600 V – Yy – Ucc = 5.23 %. It manufactures exhaust assemblies from steel plate using spot welders and… Read more
Dec 11, 2015 | By Edvard Csanyi
Transformers
The Worst Transformer Inrush Current Occurs When…
When a transformer is first energized or reenergized after a short interruption, the transformer may draw inrush current from the system due to the core magnetization being out of sync with the voltage. The inrush current may approach short-circuit levels,… Read more
Dec 09, 2015 | By Edvard Csanyi
Electric Motor
The Design Basics Of Motor Protection Circuit Breaker
Application-specific variations of the MCCB, these breakers combine the short-circuit and isolation functionality of the MCCB with the motor overcurrent protection of a traditional overload relay. MPCBs are UL 489 Listed as circuit breakers and verified as motor overload relays. These… Read more
Dec 07, 2015 | By Edvard Csanyi
Energy and Power
Learn How To Specify Current Transformers
Current transformers are used to supply information to the protective relays and/or current, power and energy metering “instruments”. For this purpose they must supply a secondary current proportional to the primary current flowing through them and must be adapted to… Read more
Dec 05, 2015 | By Edvard Csanyi
Energy and Power
7 guidelines to select correctly rated circuit breaker
The general procedure for the selection of correctly rated circuit breaker follows the following scheme of seven major questions you should answer. Let’s see the major questions: What is the task of the branch circuit or feeder? Which rated current… Read more
Dec 04, 2015 | By Edvard Csanyi
Industrial Automation
PLC Ladder Logic Functions for Electrical Engineers (Beginners)
To understand programmable logic controllers (PLCs) and their applications, you must first understand the logic concepts behind them. We’ll will explain the relationship between Boolean algebra and logic contact symbology, so that you will be ready to learn about PLC… Read more
Dec 02, 2015 | By Edvard Csanyi
Electric Motor
PLC Ladder Diagrams for Electrical Engineers (Beginners)
As an introduction to ladder diagrams, consider the simple wiring diagram for an electrical circuit in Figure 1a. The diagram shows the circuit for switching on or off an electric motor. We can redraw this diagram in a different way,… Read more
Nov 30, 2015 | By Edvard Csanyi
