Electrical Lectures
6 Adjustable Tripping Settings of a Circuit Breaker You MUST Understand
There are (at least) six basic adjustable tripping settings (functions) you really should understand in order to fully understand how circuit breaker actually works. All these adjustable functions actually shape the time-current curve of a circuit breaker and allows proper… Read more
Jun 10, 2016 | By Edvard Csanyi
Energy and Power
The basics of selectivity (discrimination) between circuit breakers
On economical grounds and for the reason of reliability of the service, it is not always ideal to interrupt the supply to the installation in the case of a fault as fast as possible. That’s why we have the selectivity… Read more
Apr 04, 2016 | By Edvard Csanyi
Power Substation
Practical Considerations of LV/MV Private Substations
Private substations can often be considered as terminal type substations, i.e. substations where the MV line ends at the point of installation of the substation itself. They belong to the user and can supply both civil users (schools, hospitals, etc.)… Read more
Mar 04, 2016 | By Edvard Csanyi
Energy and Power
The Basics Of Molded Case Circuit Breakers You MUST Know
Molded case circuit breakers are interrupting devices with self-contained, current-responsive elements. These breakers are assembled as an integral unit in a supported and enclosed housing of insulating material. Depending on the amount of protection required, these breakers can sense internally… Read more
Feb 27, 2016 | 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
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
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
Energy and Power
Automatic transfer system explained in detail (operational requirements)
In a previous article I explained the role of the automatic transfer system and the operational requirements – three modes of operation: manual mode, automatic mode, and auto mode failure. Now let’s cover the following topics and try to explain the concept… Read more
Nov 21, 2015 | By Edvard Csanyi
Energy and Power
Automatic Transfer System (ATS) Explained in Details
Using the basic building blocks of utility power, system topology, on-site generation, and uninterruptible power supplies, the basic role of the automatic transfer system may now be defined. In this role, the Automatic Transfer System must display the following characteristics:… Read more
Nov 20, 2015 | By Edvard Csanyi
Energy and Power
Eight Most Common Schemes To Supply MV Switchboard
Medium voltage networks are made up of switchboards and the connections feeding them. Let’s take a look at the eight different supply modes of these medium voltage switchboards. We’ll start with the main power supply solutions of an MV switchboard, regardless… Read more
Oct 23, 2015 | By Edvard Csanyi
Electrical Lectures
Voltage Drop Calculations For Engineers – Beginners
Voltage drop calculations using the DC-resistance formula are not always accurate for AC circuits, especially for those with a less-than-unity power factor or for those that use conductors larger than 2 AWG. Table 1 allows engineers to perform simple ac voltage drop calculations…. Read more
Sep 19, 2015 | By Edvard Csanyi
Energy and Power
Things About MCBs That Every Low Voltage Electrician Should Know
Miniature circuit breaker – MCB is a thermo-magnetic device, meaning that it has two methods of circuit interruption. A thermal mechanism, usually a bi-metallic strip, provides protection against moderate overcurrent. The heating action of the current causes the bi-metallic strip… Read more
Aug 22, 2015 | By Edvard Csanyi
Energy and Power
Example for Coordination of Cascaded Circuit Breakers
A 440 V 60 Hz switchboard feeds a 4-wire distribution board for small loads such as socket outlets. The switchboard has a fault making capacity of 100kA rms. After applying diversity factors to the loads the total load current is… Read more
Jun 24, 2015 | By Edvard Csanyi
Energy and Power
How to achieve selective coordination of circuit breakers
Selective coordination is often referred to simply as coordination. Coordination is defined in NEC® 240.2 as: “The proper localization of a fault condition to restrict outages to the equipment affected, accomplished by the choice of selective fault-protective devices.” It is… Read more
Jun 08, 2015 | By Edvard Csanyi
