The art of designing the auxiliary system of a power plant

Power plant auxiliary system is usually pretty complicated and consists of dozen of motors, transformers, capacitor banks, variable frequency drives, PLCs, and other electrical devices. Therefore, protection relaying cannot be… Read more

Feb 24, 2020 | Edvard

The basics of fault protection for medium voltage motors

In principle, the protection of medium voltage motors is similar to low voltage motors, but the requirements are more demanding. Being closer to the utility source, medium-voltage motors are more… Read more

Dec 16, 2019 | Edvard

How can a PLC and VFD be used for pump control (power and control circuits)

For the last several decades, every engineering task related to process control is realized by the use of PLC (Programmable Logic Controller). If we are talking about induction motor control,…...

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Nov 27, 2019 | Miodrag Kokotovic

Medium voltage soft starter for heavy-duty motor control (operation and special applications)

A soft starter is an electronic motor controller used on three phase medium voltage squirrel cage induction motors. During motor starting, the soft starter controls the voltage or current supplied… Read more

Nov 18, 2019 | Edvard

The wiring diagram and physical layout of the equipment inside the motor control centre

This article will provide a description of most important equipment and working principle of a real case motor control centre (MCC). That is an usual name for a switchboard with…...

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Nov 14, 2019 | Miodrag Kokotovic

How to know if you set the correct current on a motor thermal overload relay

The full-load current at a given voltage indicated on the nameplate is normative for setting the overload relay. Because of the variable voltages around the world, motors for pumps are… Read more

Sep 19, 2018 | Edvard

Earth fault protection of an AC motor in four different earthing systems

One of the most common faults to occur on a motor is a stator winding fault. Whatever the initial form of the fault (phase phase, etc.) or the cause (cyclic… Read more

Sep 10, 2018 | Edvard

Practical tips on how not to burnout an electric motor

There are many reasons why an electric motor could start heating up. For example, when another starting duty is used than the informed one on the motor nameplate this may… Read more

Aug 15, 2018 | Edvard

Why Raise the Power Factor? The Basics Every Electrical Engineer Should Understand.

A low power factor causes poor system efficiency. The total apparent power must be supplied by the electric utility. With a low power factor, or a high-kilovar component, additional generating… Read more

Jun 06, 2018 | Edvard

Protecting Motor From External Network Disturbances (Unbalance, V/Hz-ratio and Re-Energizing)

Unbalance in the supply voltage is typically due to a broken phase condition somewhere in the upstream network. This may result from single-phase fuse failure or pole discrepancy of a… Read more

Jan 29, 2018 | Edvard