The instrument readings obtained from open and short-circuit tests on 10kVA, 450/120V, 50Hz transformer are:
0.C. test : V= 120V; 1= 4.2A; W= 80W; W and I were in the low-voltage side.
S. C. test : V = 9.65V; 1= 22:24; W = 120W with low voltage winding short circuited. High voltag
S
Compute:
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The equivalent constants referred to the primary.
2- Efficiency for full and half-load at 0.8 p. f.
3- Maximum efficiency.
4- The voltage regulation-up for full-load and 0.8 p. f. lagging.

Suppose water is leaking from a tank through a circular hole of area ah at its bottom. when water leaks through a hole, friction and contraction of the stream near the hole reduce the volume of water leaving the tank per second to cah 2gh , where c (0 < c < 1) is an empirical constant. a tank in the form of a right-circular cone standing on end, vertex down, is leaking water through a circular hole in its bottom. (assume the removed apex of the cone is of negligible height and volume.) (a) suppose the tank is 20 feet high and has radius 8 feet and the circular hole has radius 2 inches. the differential equation governing the height h in feet of water leaking from a tank after t seconds is dh dt = − 5 6h3/2 . if the height of the water is initially 8 feet, how long will it take the tank to empty? (round your answer to two decimal places.)

Water is siphoned from a large tank and discharges into the atmosphere through a 50-mm diameter tube. the end of the tube is b = 2.1 m below the tank bottom which is a = 7.4 m deep, and viscous effects are negligible. determine the maximum height h over which the water can be siphoned without cavitation occurring. atmospheric pressure is 101.4 kpa, and the water vapor pressure is 1.79 kpa (absolute)

How can you increase the strength of an electromagnet?