Transformer Protection Types: Nature of Transformer Faults: Power transformers, being static, totally enclosed and oil immersed develop faults only rarely but the consequences of even a rare fault may be…
Overcurrent Protection of Feeders: Overcurrent relays offer the cheapest and the simplest protection for lines. The maximum load currents must be known to determine whether the ratio of the minimum…
Types of Feeder Protection Relay: A composite transmission system may use one or more of the following types of Feeder Protection Relay. Overcurrent Protection: This is of two types: (i)…
Important Questions in Electrical & Electronics: IMPORTANT QUESTIONS OF AC DISTRIBUTION IMPORTANT QUESTIONS OF CIRCUIT BREAKERS IMPORTANT QUESTIONS OF DC DISTRIBUTION IMPORTANT QUESTIONS OF DISTRIBUTION SYSTEMS IMPORTANT QUESTIONS OF ECONOMICS…
Important Questions of Characteristics of Electric Motors: Problems of Characteristics of Electric Motors: 1.A 50 hp, 220 V, 1200 rpm dc shunt motor has an efficiency of 85% at full…
Optocoupler Circuit Operation: An Optocoupler Circuit Operation (optoelectronic coupler) is essentially a photo-transistor and an LED combined in one package. Figure 20-35(a) and (b) shows the typical circuit and terminal…
LED Seven Segment Display: The arrangement of a LED Seven Segment Display is shown in Fig. 20-6(a). The actual LED devices are very small, so, to enlarge the lighted surface,…
UJT Circuit Diagram: UJT Circuit Diagram Operation : The Unijunction transistor (UJT) consists of a bar of lightly-doped n-type silicon with a block of p-type material on one side, [see…