Electrical Engineering Questions -

Q1. Two ideal voltage sources designated as machines 1 and 2 are connected, as shown in the figure below.

Given E₁ = 65∠0^oV, E₂ = 65∠30^oV, Z = 3Ω. Determine if

Machine 1 is generating active power and |P₁| = _______ W

Machine 2 is generating active power and |P₂| = _______ W

Machine 1 is delivering reactive power and |Q₁| = _______ var

Machine 1 is receiving reactive power and |Q₂| = _______ var

Z is absorbing _______ W.

Q2. A three-phase 440-V line is supplying a three-phase 14-hp motor operating at full load, 80% efficient and 83% power factor lagging. Find the values of P and Q drawn from the line

P = _______ (kW)

Q = _______ (kW)

Q3. Find the line-to-line voltage at the bus, which supplies 440-V line at a three-phase 18-hp motor operating at full load, 86% efficient and 85% power factor lagging. The impedance of each of the three lines connecting the bus and the motor is 0.3 + 0.8jΩ.

|V_line-to-line| = _______ (V)

Note: this question is checked to one decimal place.

Q4. A three-phase load draws 23kva at a power factor of 0.8 lagging from a 220 - V line. The kVAR of the capacitor to make the combined power factor 0.85 lagging is ______ kvar help (numbers).

Before connecting the capacitor, |I| = ______ A

After connecting the capacitor, |I| = ______ A

Note: this question is checked to two decimal places.