4. The excitation of a 414 V, 3-phase, delta-connected synchronous motor is such that that the induced emf is 520 V. The impedance per phase is 0.5 + j 4 ohms. If the friction and iron losses are constant at 1,000 W, calculate the efficiency for maximum power output.
4. The excitation of a 414 V, 3-phase, delta-connected synchronous motor is such that that the...
1. A 3-phase, 6-pole, 50-Hz, 500 kVA , 6600 V, star-connected synchronous motor has a synchronous impedance of j80 ohms per phase. For unity power factor :(i) Determine the mechanical torque neglecting all machine losses (ii) If this torque can be assumed constant, what would be the motor back emf and load angle for (a) 0.9 power factor lag and (b) 0.9 power factor lead? (iii) How will the maximum torque be...
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.
1. A 3-phase, 6-pole, 50-Hz, 500 kVA , 6600 V, star-connected synchronous motor has a synchronous impedance of j80 ohms per phase. For unity power factor :(i) Determine the mechanical torque neglecting all machine losses (ii) If this torque can be assumed constant, what would be the motor back emf and load angle for (a) 0.9 power factor lag and (b) 0.9 power factor lead? (iii) How will the maximum torque be affected in both cases?
A 440-V, 60-Hz, 4-pole, three-phase, A-connected, synchronous motor has a synchronous impedance of 1.2 + j8 n/phase. The field current is adjusted so that the excitation voltage is 560 V. When the motor develops the maximum power, determine (a) the line current, (b) the power factor, (c) the torque angle, (d) the maximum power developed, and (e) the maximum torque developed.
A 3-phase round rotor synchronous motor has a per phase terminal voltage of 480 V. This machine has a synchronous resistance and reactance of 0.25 ohm and 3.8 ohms, respectively. The excitation and field voltage of this machine is equal to 457 V and 150 V, respectively. The machine is operating at a torque angle of -8° and its field current equal to 3 A. With total rotational losses equal to 700 W, determine the following: a. Input Real and...
A three-phase delta-connected synchronous induction motor is connected to a 415 volt, 50 Hz supply. The winding resistance is negligible and the synchronous reactance per phase is 5 ohms. The input power is 20 kW and the motor has a leading power factor of 0.8. Draw the phasor diagram for this machine: ii) use the IXs phasor and the V phasor to construct the phasor for E. iii) measure or calculate the magnitude of E iv) By construction and/or by...
A 3300 V, 3-phase, 50 Hz, star-connected synchronous motor has a synchronous impedance of 2+j 15 ohms per phase. Operating with a line emf of 2500 V, it just falls out of step at full load. a) Draw the equivalent circuit of a synchronous motor. b) To what open-circuit emf will it have to be excited so that it will just remain in synchronism at 50% above rated torque? c) With this emf , what will then be: the input power; current; and ...
1. A 3300 V, 3-phase, 50 Hz, star-connected synchronous motor has a synchronous impedance of 2+j 15 per phase. Operating with a line emf of 2500 V, it just falls out of step at full load. a) Draw the equivalent circuit of a synchronous motor. b) To what open-circuit emf will it have to be excited so that it will just remain in synchronism at 50% above rated torque? c) With this emf , what will then be: the input power; current; and ...
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....
45% A 450 KVA, 2080 V, 50 Hz, 6-pole, three-phase, Y-connected, synchronous motor has a synchronous impedance of 0.5+ j15 Ohm/phase, and rotational loss is 18 kw 3, Determine: a. The excitation voltage (15%) b. The power angle (15%) c. The power developed when the motor is fully loaded at 0.8666 PF leading (15%)