A 3-phase, 400 V synchronous motor is operating in parallel with a 3-phase balanced load of...
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.
A 3-phase, 7 kVA, 400 V, 2-pole, star-connected synchronous machine has negligible armature resistance and Xs-60/phase at rated terminal voltage The machine first runs as a generator in parallel with 3-phase, 400 V, 50 Hz power supply 111 Determine the generated voltage and torque angle of the machine operating as a generator, delivering rated kVA at 0 9 pf lagging Draw and label the corresponding phasor diagram for this condition 1 12 If the field excitation is increased by 18%...
A 3-phase, star-connected synchronous motor takes current of 116 A at 0.80 lagging pf with 500 V applied. At this current, the total armature copper loss is 1,200 W. The synchronous reactance per phase of the motor is 0.30 ohm. Calculate (a) the gross mechanical power developed and (b) the core and friction losses if the full-load efficiency is 95%.
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...
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...
2) A 480 V, 60 Hz, 400 hp 0.8 PF-lagging eight-pole A-connected synchronous motor has a synchronous reactance of 0.6 and negligible armature resistance. Ignore the mechanical and core losses. The magnitude of the internal machine voltage is 480 V when the field current is 4 A. Assume magnetic linearity. Initially, the motor operates at the rated conditions. a) Find the speed of this motor. b) Find the armature and field currents. c) What is the developed torque? What is...
(Question 1): (4pts) A three-phase, 2300-V, 60-Hz, 10-pole, A-connected cylindrical rotor synchronous motor has a synchronous reactance of 4.0 82/phase. The armature resistance may be neglected. It is connected to 2300-V source and drives a system with its excitation set to give a PF of 0.9-leading when the power is 500-kW. (a) Sketch the phasor diagram of this motor. (b) Calculate the armature current. (c) Calculate the excitation voltage and torque angle. (d) If the load torque is increased by...
Three loads are being supplied from an infinite bus operating at 400 V. Load 1 is an induction motor consuming 50 kW at 0.7 PF lagging, Load 2 is an induction motor consuming 200 kW at 0.85 PF lagging. Load 3 is a synchronous motor whose real power consumption is 100 kW. If Load 3 is adjusted to operate at 0.8 PF leading, what is total current drawn from infinite bus by the loads?
1- A 25-kVA, 3-phase, wye-connected, 400-V alternator has a synchronous reactance of 1.6 ohms per phase. The alternator is to have zero voltage regulation at half-load. Neglecting the armature resistance, find the operating power factor and the developed power 2. A 500-kVA, 3600-V, 3-phase, 60-Hz alternator has an effective armature resistance per phase of 0.40 ohm Mechanical and iron losses is 10 kW, field current at full load unity power factor is 70 A. The exciter voltage is constant at...
A 2200Vrms (line-to-line), 30Hz, Y-connected, 3-phase synchronous motor has a synchronous reactance of 10Ω per phase. The motor draws 163kW at a power angle of 15°. Determine: a) The excitation voltage per phase. b) The supply current and the supply power factor. c) Draw the phasor diagram for the above condition. d) Suppose the mechanical load is now disconnected, with all the losses are negligible. Determine the new supply current and the supply power factor.