Technical Articles

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Every car has it – The Lundell generator with claw-pole rotor

Lundell generator (alternator) Increasing comfort and safety in cars, trucks, and buses driven by combustion engines require more installed electric power on board. As of now, the Lundell generator (claw-pole rotor generator) is the only type of automotive generator used in industry, with total powers per unit up to 5 kW and speeds up to 18,000 rpm. […]

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Does Transformer Hum Make You Nervous

Where Does the Sound Come From? Noise is caused by magnetostricition (changes in shape) of the core laminations while the transformer is energized. Transformers emit a low-frequency, tonal noise that people living in their vicinity experience as an irritating “hum” and can hear even against a noisy background. The electrical power industry produces a range […]

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Differential Protection – Proven Technique For More Than 50 Years

Proven Protection Technique // The best protection technique now and for more than 50 years is that known as differential protection. Here the electrical quantities entering and leaving the protected zone or area are compared by current transformers (CTs). If the net between all the various circuits is zero, it is assumed that no fault […]

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Superposition Theorem Used To Solve The Simple Network

Superposition Theorem Example // Using Superposition theorem, find the current through the 2Ω resistor of the network of Figure 1 above. The presence of three sources will result in three different networks to be analyzed. Solution // Considering the effect of the 12-V source (Fig. 2): Considering the effect of the 6V source (Fig. 3): […]

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How To Reduce Transformer Losses At Design Stage

Design changes to reduce transformer losses Design changes to reduce transformer losses, just as in a motor, always involve trade offs. For example, consider varying the cross-sectional area of the transformer core. An increase tends to lower no-load loss while raising the winding loss. An increase in volts per turn reduces winding loss while increasing […]

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Purpose And Applicable Processes Of a SCADA System

What is the SCADA system? SCADA is the technology that enables a user to collect data from one or more distant facilities and to send limited control instructions to those facilities. It is important to note the words “distant” and “limited” in this definition. SCADA has been developed to monitor and control very large process facilities. […]

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Features of 3 circuit protection devices (MCB, RCCB and RCBO) you have probably forgotten

Circuit Protection Devices Traditionally, fuses were the main devices chosen for final circuit protection, up until the 1970’s when circuit breaker technology started to become dominant. Today, the three principle circuit protection devices are: Miniature Circuit Breakers (MCBs), Residual Current Circuit Breakers (RCCBs) and Residual Current Circuit Breakers with Overcurrent protection (RCBOs) Miniature Circuit Breakers […]

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Electric Circuits? It’s All About Nodes, Branches, and Loops

Nodes, Branches, and Loops Since the elements of an electric circuit can be interconnected in several ways, we need to understand some basic concepts of network topology. To differentiate between a circuit and a network, we may regard a network as an interconnection of elements or devices, whereas a circuit is a network providing one […]

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What Would Be The Worst Type Of Three Phase Faults (And Why It Happens)

When Three Phase Faults Occur… In a three phase power system, the type of faults that can occur are classified by the combination of conductors or buses that are faulted together. In addition, faults may be classified as either bolted faults or faults that occur through some impedance such as an arc. Each of the basic […]

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3 Designs of DC Distribution Systems In Power Substations

DC Distribution Systems The method of connection of the battery, battery charger, and DC distribution systems depends on the duty, the type or load, and whether the system needs to be duplicated or whether duplicate chargers are required. One typical example for a 125 V system is shown in figure 1 below. In this example, an […]

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