Auto Transformer

An autotransformer is a somewhat electrical transformer where essential and auxiliary offers the same basic single winding. So fundamentally it's a one winding transformer.

Theory of Auto Transformer

In Auto Transformer, one single winding is utilized as essential twisting and also auxiliary winding. In any case, in two windings transformer, two unique windings are utilized for an essential and auxiliary reason. An outline of the autotransformer is demonstrated as follows.

The twisting AB of aggregate turns N1 is considered an essential winding. This winding is tapped from point ′C′ and part BC is considered as an auxiliary. How about we expect the quantity of turns in the middle of focuses ′B′ and ′C′ is N2.

Limitations of Terzaghi Theory

Limitations of Terzaghi Theory The value of the coefficient of consolidation has been assumed to be constant. The distance d of the drainage path cannot be measured accurately in the field. The thickness of the deposit is generally variable, and an average value has to be estimated. There is sometimes difficulty 1n locating the drainage face, sometimes thin previous seams that can act as good drainage face are missed in the boring operations. The equation is based on the assumption that the consolidation is one-dimensional. In the field, the consolidation is generally 3-dimensional. The lateral drainage may have a significant effect on the time rate of consolidation. The initial consolidation and secondary consolidation have been neglected. Sometimes these form an important part of the total consolidation. In actual practice, the pressure distribution may be far from linear or uniform. Read More Muller-Breslau principle

Price Guard Wire Method

Price Guard Wire Method Some form of Price Guard Wire Method is generally used to eliminate the errors caused by leakage currents over insulation. Fig. 3.14 illustrates the operation of This Method. In fig 3.14(a), a high resistance mounted on a piece of insulating material is measured by the ammeter voltmeter method. The micro-ammeter measures the sum of the current through the resistor (IR) and the current through the leakage path around the resistor. The measured value of resistance computed from the readings indicated on the voltmeter and the microammeter, will not be a true value but will be in error. Figure 3.14 Application of guard circuit for measurement of high resistance In fig, 3.14 (b), the guard terminal has been added to the resistance terminal block. The guard terminal surrounds the resistance terminal entirely and is connected to the battery side of the micro-ammeter. The leakage current IL now bypasses t

Negative Booster

Negative booster A negative booster is employed to conform to the regulation that the potential difference between any two points of the rail return shall not exceed 7 V. Two boosters, positive and negative, are used which are mechanically coupled together and driven by a DC motor. The positive booster is connected to the trolley wire (near the generating station) and the negative booster (separately excited) is connected to the track rail. The 'positive booster' adds voltage to the line while the 'negative booster lowers the potential of the point it is connected to. As we go along the trolley wire away from the generating station/sub-station, the potential drop increases, and the voltage of the trolley wire falls. Since the current returns via the track rail points away from the generating station acquire high potentials. This potential is brought down by the negative boost provided by the negative booster. When the load is sufficiently far away from the generating stati

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