Given Information:
Balanced Y-Y three phase circuit
Phase Voltage = Van = 120 < 10° V
Load Impedance = Zy = 20 +j15 Ω = 25 < 36.86° Ω
Required Information:
Load Voltages = Vab, Vbc, Vca = ?
Line currents = Ia, Ib, Ic = ?
Answer:
Vab = 208 < 40°
Vbc = 208 < -80°
Vca = 208 < 160°
Ia = 4.8 < -26.86°
Ib = 4.8 < -146.86°
Ic = 4.8 < 93.14°
Explanation:
Since it is balanced 3 phase system, all phases have equal magnitude and 120° phase shift
Van = 120 < 10° V
Vbn = 120 < -110° V
Vcn = 120 < 130° V
In a Y connected system, the phase voltage and line voltage are related as
Vab = (Van) <+30°
Vab = *120<10°+30°
Vab = 208 < 40°
Vbc = 208 < -80°
Vca = 208 < 160°
In a Y connected circuit, Iphase = Iline
Ia = Van/Zy
Ia = 120 < 10°/25 < 36.86°
Ia = 4.8 < -26.86°
Ib = 4.8 < -146.86°
Ic = 4.8 < 93.14°
Answer:
a) 0.01558 Ω per 1000 feet
b) 0.0923 Ω per mile
c) 3.57%
Explanation:
<u>a) Calculate and verify the DC resistance </u>
Dc resistance = R = р
for aluminum at 20°C
р = 17 Ωcmil/ft
hence R = 17 * 1000 / ( 113000 ) = 0.01527 Ω per 1000 feet
there when there is an increase in resistance of 2% spiraling
R = 1.02 * 0.01527 = 0.01558 Ω per 1000 feet
<u>b) Calculate the DC resistance at 50°C </u>
R2 = R1 ( )
where ; R1 = 0.01558 , T = 228 , t2 = 50, t1 = 20 ( input values into equation above )
hence R2 = ( 0.01746 / 0.189 ) Ω per mile = 0.0923 Ω per mile
<u>c ) Determine the percentage increase due to skin effect </u>
AC resistance = 0.0956 ohm per mile
Hence; Increase in skin effect
= ( 0.0956 -0.0923 ) / 0.0923
= 0.0357 ≈ 3.57%
See explanations
Explanation:
In this case, when the collar mass is released, it will move from the rest point, to a point between A and B and then to point C. While it approaches point C, the amount of stretch will decrease and the spring force will reduce.At point C, the spring reaches its maximum stretch, leaving un-stretched length of spring l, making point C the position where the velocity of the collar is maximum.The energy possessed due to motion of the collar is kinetic energy, thus the magnitude of the velocity can be calculated from;
Kinetic energy, K.E = 1/2*m*v²
Thus
where m is mass of collar and v is speed of collar. The faster the collar the more the kinetic energy.
Learn More
Spring kinetic energy :brainly.com/question/13866407
Keywords :spring, spring constant, support, collar mass, unstretched length, friction, horizontal rod
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