b) The load connected to a three-phase supply comprises three similar coils connected in star. If...

b) The load connected to a three-phase supply comprises three similar coils connected in star. If the phase currents are 10A and the total active power and power factor absorb by the loads are 3kW and 0.8 lagging, respectively. Find:
i. The magnitude of phase and line voltages
ii. Total apparent power (1 mark)
iii. The impedance of each coil.
c) If the coil in Q3(b) are now connected in delta to the same three-phase supply, calculate the magnitude of the line currents and the magnitude of the total apparent power.
[25 marks]

Expert Solution

Manojponduru answered 2 years ago

A balanced three-phase delta-connected load is connected to a balanced three-phase delta-connected source via a transmission...

A balanced three-phase delta-connected load is connected to a balanced three-phase delta-connected source via a transmission line. The line-line voltage for the source is 100∟0° V/phase and the impedance of load is (27 + j18) Ω/phase. The transmission line has an impedance of (1 + j4) Ω/line. a) Draw the complete schematic of the power system showing the location of wattmeters. (Two-Wattmeter system is considered for this problem). Phase “a” could be considered as a reference phase. b) What must...

An unbalanced three-phase wye-connected and grounded load is connected to a balanced three-phase four-wire source. The...

An unbalanced three-phase wye-connected and grounded load is connected to a balanced three-phase four-wire source. The load impedances are Za = 14+j3 Ω , Zb = 5-j24Ω and Zc =1+j14 Ω and the phase a line voltage has an effective value of 18 Kv: use line-to-neutral voltage of phase A as a reference. Find the line and neutral current, also find the reactive power delivered to load and power factor.

Three balanced three-phase loads are connected in parallel. Load 1 is Y-connected with an impedance of...

Three balanced three-phase loads are connected in parallel. Load 1 is Y-connected with an impedance of 420+300i Ω/ϕ ; load 2 is Δ-connected with an impedance of 2400-1780i Ω/ϕ ; and load 3 is 170.1+2201i kVA . The loads are fed from a distribution line with an impedance of 2+17i Ω/ϕ . The magnitude of the line-to-neutral voltage at the load end of the line is 23√3 kV. Part A: Calculate the total complex power at the sending end of...

A three-phase balanced star load No. 1 of (120 +j90) ohms in parallel with another three-phase...

A three-phase balanced star load No. 1 of (120 +j90) ohms in parallel with another three-phase balanced star load No. 2 of (90 +j120) ohms, both are fed by three-phase balanced conductors of 3 ohms resistance and 4 ohms reactance. If the generator is 240 volts, with angle of -150° on phase c and reactance of 1 ohms, determine: a) the current on load N°1 on phase C, b) the terminal voltage of the generator on phase B, c) the...

Three balanced 3-phase loads are connected in parallel. Load 1 is Y-connected with an impedance of...

Three balanced 3-phase loads are connected in parallel. Load 1 is Y-connected with an impedance of 400 + j300 ? per phase, load 2 is ?-connected with an impedance of 2400 – j1800 ? per phase, and load 3 is absorbing 172.8 + j2203.2 kVA. The loads are fed from a set of distribution lines with an impedance of 2 + j16 ? per line. The magnitude of the line-to-neutral voltage at the load end of the line is 24?3...

An unbalanced wye connected wye connected load of three phase resistances with Ra=60 ohms, Rb=40 ohms...

An unbalanced wye connected wye connected load of three phase resistances with Ra=60 ohms, Rb=40 ohms and Rc=80 ohms is connected to a 440V, negative sequence, balanced 3 phase, 3 wire supply. Calculate the complex power using the method of symmetrical components. Please show all steps and clearly show all answers.

A three phase transformer of 400kVA, 10kV/400V, Dy11 is connected to its nominal load with cosφ...

A three phase transformer of 400kVA, 10kV/400V, Dy11 is connected to its nominal load with cosφ = 1. a) Calculate the nominal primary and secondary line current. b) Calculate the corresponding currents in the primary and secondary winding. At an open circuit test, the primary line current is 0,52A with cosφ = 0,05 at nominal line voltage. The short circuit test (at nominal current) shows 214V primary line voltage and P=1,333kW per phase. c) Calculate the total iron losses and...

Question 5 a) Draw the circuit of a Three-phase bridge inverter using a Y-connected load and...

Question 5 a) Draw the circuit of a Three-phase bridge inverter using a Y-connected load and explain its operation using 180 degree conduction clearly showing the gating sequence and the corresponding output line voltages for each phase. (10) b) For the Y-connected load determine the line to neutral voltages for the three modes of operations. Draw the equivalent circuits for each mode and then draw the phase voltage waveforms for the 180-degree conduction. (7)

A balanced three-phase generator delivers 6.3 kW to a delta-connected load with impedance 13 - j23.4...

A balanced three-phase generator delivers 6.3 kW to a delta-connected load with impedance 13 - j23.4 Ω per phase. The magnitude of the line current ILis:

A three phase 10kW, 1700rpm, 60Hz, four poles, Y connected induction motor has a no-load speed...

A three phase 10kW, 1700rpm, 60Hz, four poles, Y connected induction motor has a no-load speed of 1750rpm. The rotational mechanical losses are constant and equal to 500W. The core losses are constant and equal to 300W. The copper losses in the stator equal to the copper losses in the rotor at full load. If the rotor resistance per phase is 0.25?, calculate the following: a.The frequency of the induced current in the rotor circuit at full load. b.The percentage...

Question