Shunts

The mmen is not functional at birth and milk is shunted to the abomasum. One to two weeks after birth, the neonate consumes soHd food if offered. A calf or lamb that is nursing tends to nibble the mother s feed. An alternative method of raising the neonate is to remove it from its mother at a very young age, <1 week. A common example of an early weaning situation is the dairy calf that is removed from the cow soon after birth so that the cow s milk supply might be devoted entirely to production. In this instance, the neonate requires complete dietary supplementation with milk replacer. Sources of milk replacer protein have traditionally included milk protein but may also include soybean proteins, fish protein concentrates, field bean proteins, pea protein concentrates, and yeast protein (4). Information on the digestibiUty of some of these protein sources is available (4). 

Ni alloys of 30—32 wt % are used as temperature-compensator alloys and are characterized by a steep decrease ia magnetic permeabiUty with temperature. These alloys are ideally suited ia electrical circuits as shunts which maintain constant magnetic strength ia devices such as electric meters, voltage regulators, and speedometers. 

Usually, copper surfaces are mated when joints must be periodically discoimected because copper offers low resistance and good wear. Junctions between copper and aluminum bus bars are improved by using a copper—aluminum transition joint that is welded to the aluminum member. Deterioration of aluminum shunt connections by arcing is eliminated when a transition joint is welded to both the primary bar and the shunting bar. 

Compound-wound dc motors have both series and shunt fields. The addition of a small series field helps provide the proper amount of no-load to fuU-load speed regulation or droop. Shunt or compound-wound motors are apphed widely to many adjustable-speed drives. They are important for drives requiring accurate speed regulation and adjustment. 

A dc motors inherent speed-torque curve can be varied widely by adjusting the relative amounts of shunt and series fields. The series field may also be connected to aid or buck the shunt field. The usual practice is to connect the series field so that it adds to the shunt field (cumulative compound), which gives a stable, drooping speed with increasing load. 

One of the oldest adjustable-speed drives is the Ward-Leonard system. This consists of an ac to dc motor-generator set and a shunt or compound-wound dc motor. Speed is adjusted by changing the generator voltage. A functional equivalent of this drive uses an adjustable-voltage rectifier feeding a dc motor. This system has only one rotating machine in contrast to the three of a conventional Ward-Leonard system. 

The electrical interlocking should preferably be provided through shunt trip releases. It must have a separate a.c. or d.c. source of control supply, such that the operation of the scheme is independent of the main source of supply. For the same reason, interlocking through undervoltage (U/V) releases is not recommended as its... 

The function of a shunt trip coil is to trip an intetrupter. As. soon as its coil is energized, it releases the closing lever of the interrupter and trips it. The coil is rated for a short time, since it is in the circuit for a very, short period only when it is required to trip the interrupter. To ensure that it does not continue to remain energized after carrying out its function, the interrupter s NO contacts are also wired in scries with the coil as shown. The coil becomes de-energized as soon as the interrupter trips. Normally two NO contacts of the... 

To close or trip the interrupter locally or retnotely a breaker control switch is also wired with the closing and the shunt trip coils of the interrupter, as shown in Figure... 

J) Source side resistance R (to control the p.f. as per the test requirements) High current step down transformer Test object (j Current shunt (2) R-C voltage dividers (12) Recording instruments ... 

When the systems that are series compensated are eonneeted to a lightly loaded transformer or shunt reactor, under certain line conditions (Section 24.4). 

Resonance may also occur between the line inductance, series reactors and shunt capacitors. 

This practice is usually adopted in oil circuit breakers (BOCBs and MOCBs). In air blast circuit breakers (ABCBs), and SF(, circuit breakers, a resistance is connected in shunt across the contact gap. such that R is introduced in the circuit during the making and interrupting processes only. 

Shunt capacitor - connected across the inductive circuit to improve its p.f. 

Harmonic output of a capacitor unit The rating of a shunt capacitor unit... 

If Xl is the 6% series reactance of the value of the shunt capacitors installed, then... 

Shunt capacitors 1120 kVAr in each arm of a double star as shown below. Each unit 80 kVAr... 

Figure 23.18(b) Network of Figure 24.25 shown with shunt compensation... 

The shunt capacitors can be provided on the LT or the HT side, whichever is more convenient. In the above case, since it is large, the HT side of the load-end transformer will be more convenient. The receiving-end transformer, however, will now be operating under more stringent conditions that must be taken in account or the capacitors may be provided on the LT side to relieve this transformer also from excessive currents. In Figure 23.18(b) we have considered them on the LT side. 

Figure 23.29(a) Determining the kVAr rating of a shunt capacitor... 

Shunt power capacitors of the self healing type for a.c. systems having rated voltage up to and including 1000 V 13340/1993 BS EN 608.31 -1/1998... 

Shunt capacitors for a.c. power system having rated voltages above 1000 V I3925-I/I998 BS EN 60871-1/1998... 

Shunt power capacitors of non self-healing types up to and including 1000 V General performance, testing and rating. Safety requirements. Guide for installation and operation 13585-1/1994 BS EN 60931-1/1996... 

Series and shunt capacitors both provide the same degree of compensation. But it is the correct reactive support that provides a more stable system less prone to load and voltage lluctuations. Thus i Judicious choice between the shunt and the series capacitors is required. In the following our main thrust is to arrive at the most appropriate type and extent of reactive support to achieve a higher level of utilization of a power transmission or distribution system, on the one hand, and more stability, on the other. 

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