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
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
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
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
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
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
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
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
HV/MV/LV Transformer Protection Schemes
Transformer protection should take into account the power, voltage, vector group and the importance of the unit within a particular system. Depending on these factors, the transformers can be assigned to one of the two general groups. Let’s see these… Read more
Nov 28, 2015 | By Edvard Csanyi
Comparison of 4 Different Flow Control Methods Of Pumps
When in use, the pumps are always part of a pumping system. A pumping system is usually a network of pipes, tanks, valves and other system parts. The receiver is usually at a higher geographic level than the supply of… Read more
Nov 27, 2015 | By Edvard Csanyi
The Mesh Current Method For Analysis Of Electric Circuits
The mesh current method of circuit analysis discussed in this technical article employs mesh currents as the independent variables. The idea is to write the appropriate number of independent equations, using mesh currents as the independent variables. Subsequent application of… Read more
Nov 25, 2015 | By Edvard Csanyi
Guidelines to electrical braking of asynchronous motors
In many industrial systems, motors are stopped simply by natural deceleration. The time this takes depends solely on the inertia and resistive torque of the machine the motor drives. However, the time often needs to be cut down and electrical… Read more
Nov 23, 2015 | By Edvard Csanyi
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
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
Example On How To Design a Low Voltage Switchboard
This technical article has the aim of helping the panel builder and the designer in the construction of ABB SACE ArTu low voltage switchboard. To this purpose, starting from the single-line diagram of a plant, it is possible to arrive… Read more
Nov 18, 2015 | By Edvard Csanyi
