480 V, 200 kVA, 08 PF lagging, 60 Hz two pole Y connected synchronous generator has...

480 V, 200 kVA, 08 PF lagging, 60 Hz two pole Y connected synchronous generator has a synchronous reactance of 0.25 Ω and an armature resistance of 0.03 Ω. At 60 Hz, its friction and windage losses are 6 kW, and its core losses are 4 kW. The field circuit has a dc voltage of 200 V, and the maximum IF is 10 A. The resistance of the field circuit is adjustable over the range from 20 to 200 Ω. The OCC of the generator is shown in figure

a. How much the field current is required to make VT equal to 480 V when the generator is running at no load? [4.55 A]

b. What the internal generated voltage of this machine at rated conditions? [322 @ 7.8°]

c. How much the field current is required to make VT equal to 480 V when the generator is running at rated conditions? [558 V]

d. How much power and torque must the generator’s prime mover be capable of supplying? [175.2 kW, 465 Nm]

e. Assume that the field current of the generator is adjusted to achieve rated voltage (480 V) at full load conditions in each of the questions below.

1. What is the efficiency of the generator at rated load? [91.3%]

2. What is the voltage regulation of the generator if it is loaded to rated kilovoltamperes with 0.8-PF lagging loads? [16.2%]

3. What is the voltage regulation of the generator if it is loaded to rated kilovoltamperes with 0.8-PF leading loads? [-9.0%]

4. What is the voltage regulation of the generator if it is loaded to rated kilovoltamperes with unity power-factor loads? [5.1%]

f. Assume that the field current of the generator in Problem 5-2 has been adjusted so that it supplies rated voltage when loaded with rated current at unity power factor. (You may ignore the effects of RA when answering these questions.)

1. What is the torque angle δ of the generator when supplying rated current at unity power factor? [12°]

2. What is the maximum power that this generator can deliver to a unity power factor load when the field current is adjusted to the current value? [941 kW]

3. When this generator is running at full load with unity power factor, how close is it to the static stability limit of the machine? [196 kW]

4. Plot the torque angle δ as a function of the power supplied by the generator for these conditions.

3. A 3-phase 50-Hz star-connected 2000-kVA, 2300 V

Solutions

Expert Solution

Manojponduru answered 7 months ago

Next > < Previous

Related Solutions

A three phase, 60 Hz, 480 V, Y-connected, two-pole synchronous generator has a synchronous reactance of...

A three phase, 60 Hz, 480 V, Y-connected, two-pole synchronous generator has a synchronous reactance of 0.95 Ω per phase. Its armature resistance is negligible. Its combined friction and windage losses are 1.3 kW and its core losses are 0.95 kW. The field current is constant at no-load. Its full load armature current is 55 A at 0.9PF lagging. Assume phase voltage is a reference. Determine following: a) Its terminal voltage when it is loaded with the rated current at...

A 480 V, 50 Hz, Y-connected six-pole synchronous generator has a per-phase synchronous reactance of 1.0...

A 480 V, 50 Hz, Y-connected six-pole synchronous generator has a per-phase synchronous reactance of 1.0 Ω. Its full-load armature current is 60 A at 0.8 PF lagging. Its friction and windage losses are 1.5 kW and core losses are 1.0 kW at 60 Hz at full load. Assume that the armature resistance (and, therefore, the I2R losses) can be ignored. The field current has been adjusted such that the no-load terminal voltage is 480 V. a. What is the...

1- A 480-V, 60-Hz, delta connected, synchronous generator has a synchronous reactance of 0.5 ohm and...

1- A 480-V, 60-Hz, delta connected, synchronous generator has a synchronous reactance of 0.5 ohm and Its rated Line current is 100 A. if the generator is connected to a 480V grid Draw the phasor diagram and find EA, delta angle and output power under the following conditions a- The generator supply the rated current at 0.8 PF lagging. b-The generator supply the rated current at 1.0 PF. c- The generator supply the rated current at 0.8 PF leading.

A 3-phase, 5 kVA, 208 V, 4-pole, 60 Hz, star-connected synchronous generator has negligible stator winding...

A 3-phase, 5 kVA, 208 V, 4-pole, 60 Hz, star-connected synchronous generator has negligible stator winding resistance and a synchronous reactance of 8 Ω per phase at the rated terminal voltage. The generator is connected in parallel to a 3-phase, 208 V, 60 Hz infinite bus. All losses may be neglected. a) Determine the excitation voltage and the power angle when the machine is delivering rated apparent power at 0.8 PF lagging. b) If the field excitation is increased by...

A 3-phase, 5 kVA, 208 V, four-pole, 60 Hz, Y-connected synchronous machine has negligible stator winding...

A 3-phase, 5 kVA, 208 V, four-pole, 60 Hz, Y-connected synchronous machine has negligible stator winding resistance and a synchronous reactance of 8 per phase at rated terminal voltage. Themachine is operated as a generator and delivers rated kVA at 0.8 power factor lagging. (a) Determine the excitation voltage, (b) Find the power angle, (c) Draw the phasor diagram, (d) Find the stator current assuming that the field excitation current is now increased by 20 % (without changing the prime...

396 v, 60 Hz, 600 hp, 0.6 pf-leading, four-pole triangle connected synchronous motor has 0.9Ω synchronous...

396 v, 60 Hz, 600 hp, 0.6 pf-leading, four-pole triangle connected synchronous motor has 0.9Ω synchronous reactance. Friction; wind; core losses and armature resistance are neglected. a) If the motor is operating under magnitude of phase current (ia) 216 Ampere and power factor of 0.6 lagging, 1. Find the input power of motor in hp ( 2. Find the generated voltage, EA 3. Find the torque and the maximum inducible torque in current state. b) If EA is increased by...

1. 414 Volt, 60 Hz, 600 hp, 0.6 pf-leading, four-pole triangle connected synchronous motor has 0.9Ω...

1. 414 Volt, 60 Hz, 600 hp, 0.6 pf-leading, four-pole triangle connected synchronous motor has 0.9Ω synchronous reactance. Friction; wind; core losses and armature resistance are neglected. a) If the motor is operating under magnitude of phase current (ia) 234 Ampere and power factor of 0.6 lagging, 1. Find the input power of motor in hp (10p) 2. Find the generated voltage, EA (10p) 3. Find the torque and the maximum inducible torque in current state. (10p) b) If EA...

Consider two equal non sallent pole three phase 60 cycle Y connected 6600 volt 10000-kva synchronous...

Consider two equal non sallent pole three phase 60 cycle Y connected 6600 volt 10000-kva synchronous generators, each wuth an effective resistance of 0.063 ohm per phase and a synchronous reactance of 1.52 ohm per phase. Assume that the resistances and reactances of the generators are constant. These generators in parallel carry an inductive load of 18000 kva at 0.9 power factor. (a) find the excitation voltages of the generators and their power angles when they share the kw load...

For synchronous generator to work at lagging PF and unity PF, which one have more efficiency?...

For synchronous generator to work at lagging PF and unity PF, which one have more efficiency? Why? (Ra is not equal to zero)

A Y- connected, 460- V, 1710- rpm, 60- Hz, 4- pole squirrel cage induction motor has...

A Y- connected, 460- V, 1710- rpm, 60- Hz, 4- pole squirrel cage induction motor has a rotor current at starting 6 times the rotor current at full load. Calculate: a. The starting torque as percent of full load torque. b. The slip and speed at which the motor develops maximum torque. c. The maximum torque developed b the motor as percent of its full load value.

Subjects