Electrical Engineering Answers

Based on Figure 2(c), using Delta-Star transformation, calculate resistance RT and total current,

IT for circuit below.(5 marks)

Figure 1(c)

A generating station consists of two 100 MVA generators with 6%

reactance each and one 150 MVA generator with 8% reactance as shown

in Figure below. These generators are connected to a common bus bar

from which loads are taken through a number of 50 MVA, step up

transformers each having 5% reactance. Compute the rating of circuit

breaker on (i) low voltage side and (ii) on high voltage side.

3. For the magnetic circuit shown in figure 21.19 the reluctance of the central limb (PS) is 10 × 105 AT/Wb and the reluctance of the outer limbs (PTS and PQS) are same and equal to 15 × 105 AT/Wb. To produce 0.5 mWb in PQS, the mmf to be produced by the coil is: (A) 750 AT (B) 1750 AT (C) 250 AT (D) 1500 AT.

minimized the following boolean expression using K-map and boolean algebra. Draw the schematic diagram of the minimized expression. X= A’B’C’D+ A’B’C’D+A’BC’D

A resistive coil draws 2A at 110 V after operating for a long time. If the temperature rise is 55°C above the ambient temperature of 20°C, calculate the external resistance which must be initially connected in series with the coil to limit the current to 2A. The temperature coefficient of the material of the coil is 0.0043 per °C at 20°C.

when does a signal is said to be valid or invalid?