Summary- The excitation voltage is derrived using formulas of Synchronous Motor
Note- As per solution is concerned,there's some data given doesn't fit for the solution.To have the correct answer with given data is beyond the scope.A review for question is required. (P.S- the magnitude formula of current gives the complex result)
A 3-phase, 6,600 V, 6,000 HP, star-connected synchronous motor is to be operated under rated conditions...
A 208 V, star-connected, 3-phase synchronous motor has a synchronous reactance of 4 ohms/phase and negligible armature winding resistance. At a certain load, the motor takes 7.2 kW at 0.8 pf lagging. If the power developed by the motor remains the same while the excitation voltage is increased by 50% by raising the field excitation, determine (a) the new armature current and (b) the new power factor.
3. The nameplate of a Y-connected synchronous motor has the following information. Hp 20,000, RPM 1800, PF 1.0 Volts 6600, Ampere 1350, Phase 3, Frequency 60 The per-unit reactance Excitation voltage 120, Amp 5.5 is X, = 0.95, and the per-unit resistance is R = 0.012 A. Determine X, and R, in ohms. B. For rated (full-load) condition (i) Determine the output torque in Nm. (ii) Determine the rotational loss. (iii) Determine the efficiency.
A 1500 kW, unity pf, 3-phase, Y-connected, 2300 V-(line), 30 pole, 60 Hz synchronous motor has a synchronous reactance of 1.95 22/phase. For this problem all losses may be neglected. a. Compute the max. torque in Nm which this motor can deliver if it is supplied with power from an infinite bus, and if its field excitation is constant at the value which would result in unity (1.0) pf at rated load. b. Now, suppose that the motor is supplied...
Problem 2 A 15 HP, 96% efficient, three-phase Wye-connected synchronous motor is connected to a 480 VAC, 60 Hz power supply. The field excitation is set such that the power factor is 0.97 leading. The machine draws 9 kW from the supplv. The per-phase armature reactance is 9500. Find the internally generated voltage, E, Calculate the motor torque angle, δ. Draw the phasor diagram, showing Vn E, XsL, IA ,Θ and δ. a. b. c.
Problem 2 A 15 HP,...
Electric Machines - Synchronous Motors
4. A 150 kVA, 460-V, four pole, 60 Hz, three phase, Y-connected synchronous motor operatingat rated load has a synchronous reactance of 1.20 ohms/phase, determine: Excitation voltage Power angle Pull-out torque Draw a phasor diagram a. b. c. d.
4. A 150 kVA, 460-V, four pole, 60 Hz, three phase, Y-connected synchronous motor operatingat rated load has a synchronous reactance of 1.20 ohms/phase, determine: Excitation voltage Power angle Pull-out torque Draw a phasor diagram a....
A 6.6 kV, star-connected, 3-phase, synchronous motor works at constant voltage and constant excitation. Its synchronous impedance is (2.0 + j20) per phase. When the input is 1000 kW, its power factor is 0.8 leading. Find the power factor when the input is increased to 1500 kW Answer is 0.925 leading
A 1500-kVA, 6.6 kV, 50 Hz, 6-pole, three-phase, star-connected
synchronous generator has a resistance 0.5Q/phase and a synchronous
reactance of 5Q/phase. The generator is supplying its rated power
at its rated voltage and at a power factor lagging. The rotational
loss is 2 kW. Calculate:
(a) the power developed,
(b) the power angle,
(c) the voltage regulation, and
(d) the shaft torque.
A 1500-kVA, 6.6 kV, 50 Hz, 6-pole, three-phase, star-connected synchronous generator has a resistance 0.50/phase and a synchronous...
Q3) A 400-V, 3-phase, 50-HZ, 4-pole Y-connected synchronous machine is operated as a motor and draws 27A at 0.77 PF leading. The motor armature resistance is 0.50/Phase and synchronous reactance is j12Ω /phase. The rotational loss is 200 watts. The field winding has a resistance of 0.4Ω and is supplied by 50V DC sources. Determine the following: a) Real and reactive power drawn by the motor b) The power developed c) The torque angle d) The shaft torque e) Efficiency...
Question 4 (10 marks) A) A 10-kVA, 415-V, three phase, Y -connected synchronous generator has a winding resistance of 0.3 Q and a synchronous reactance of 0.6 on a per phase basis. Determine its voltage regulation at full load when the power factor is (a) 75% lagging and (b) 75% leading. B) (10 marks) A 220-V, Y-connected, three-phase, synchronous motor has a synchronous reactance of 4 O/phase and negligible armature winding resistance. At a certain load the motor takes 7.5...
Problem 3) [15 marks] A 200-V, 100-hp, 0.6 PF leading, Y-connected, 50 Hz synchronous motor has a synchronous reactance of2.0 Ω and negligible resistance. Its mechanical losses and core losses are 1 .0 Kw and 0.5 KW, respectively. The shaft is supplying a 20-hp load at 0.6 PF leading. a) Sketch the phasor diagram of the machine and find the values of IA, I, and EA. b) The load is now increased to 40 hp. Repeat part (a) and find...