Ask Question, Ask an Expert

+1-415-315-9853

info@mywordsolution.com

Ask Electrical & Electronics Expert

problem1) The three-phase 50 Hz synchronous generator is operating at unity power factor, with following conditions: line-line voltage 13kV, stator current 1000A, field current 80A, torque angle 20°

a) Determine:

i) magnitude of the induced voltage E, and

ii) value of the synchronous inductance Ls

b) It is now desired to supply 8MVARs (lagging) while maintaining the similar real power as above. Sketch the phasor diagram showing E, V, and I for this case, and determine numerical values for

i) the new field current, and

ii) the new torque angle δ.

problem 2) Estimate the value of the distribution factor for three-phase alternator having 12slots/pole. [0.958]

problem3) The three-phase winding is housed in 3 slots/pole/phase. Two slots cord the winding. Estimate the coil span factor for:

a) The fundamental [0.939]

b) The 3rd harmonic [0.5]

c) The 6th harmonic [-0.5]

problem4) Find out the regulation of the three-phase, star-connected, 500-kVA, 3300-V, alternator for power-factors of 1, 0.8 lagging and 0.8 leading. The synchronous reactance is 4 ! and the resistance is 0.7 !. [4.84% ; 14.37% ; -6.95%]

Theory problems

problem1) Does change in excitation affect synchronous motor speed?

problem2) Does change in excitation affect the power factor?

problem3) How does excitation affect power factor?

problem4) For what service are synchronous motors especially suited?

problem5) Which has more efficiency; synchronous or induction motor?

problem6) Mention some specific applications of synchronous motor?

problem7) What is the synchronous capacitor?

problem8) What are the causes of faulty starting of a synchronous motor?

problem9) What could be the reasons if a synchronous motor fails to start?

problem10) A synchronous motor starts as usual but fails to develop its full torque. What could it be due to?

Electrical & Electronics, Engineering

  • Category:- Electrical & Electronics
  • Reference No.:- M9579

Have any Question? 


Related Questions in Electrical & Electronics

A motor can be represented by a resistance r and inductance

A motor can be represented by a resistance R and inductance L in series. If this motor has a power factor of 0.866 at a frequency of 60 Hz, what will the power factor be for a frequency of 440 Hz?

A 10-hp 230-volt shunt-wound motor has rated speed of 1000

A 10-hp, 230-volt shunt-wound motor has rated speed of 1,000 rev/min and full-load efficiency of 86 percent. Armature circuit resistance is 0.26 Ω; field-circuit resistance is 225 Ω. If this motor is operating under rate ...

Assume that the coupling between the motor and the inertial

Assume that the coupling between the motor and the inertial load of the proceding problem is flexible (e.g., a long shaft). This can be modeled by adding a torsional spring between the motor inertia and the load inertia. ...

The capacitor of given figure is initially charged to 3 v

The capacitor of given figure is initially charged to 3 V with the polarity shown. a. Write the mathematical expressions for the voltage v C  and the current i C  when the switch is closed. b. Sketch the waveforms of v C ...

An inverting amplifier with gain of -100 vn and an input

An inverting amplifier with gain of -100 VN and an input resistance of 100 ;a uses an op amp with I mV offset, a bias current of 30 nA and an offset current of 3 nA. What output offset results with a) a basic uncompensat ...

At a temperature of c the resistances of a type of

At a temperature of C, the resistances of a type of thermistor are normally distributed with a mean of 10,000 ohms and a standard deviation of 4,000 ohms. The thermistors are to be sorted, with those having resistances b ...

A 4-pole lap wound dc armature has a bore diameter of 07m

A 4-pole lap wound d.c armature has a bore diameter of 0.7m. It has 560 conductors and the ratio of pole arc/pole pitch is 0.63. the armature is running at 600 rpm and the flux density in the air gap is 1.2 wb/m 2 . Dete ...

A calculate the number of free electrons per cubic

(a) Calculate the number of free electrons per cubic centimeter in copper, assuming that the maximum energy of these electrons equals the Fenni energy (m* = mol.) (b) How does this result compare with that detennined dir ...

Part asimplify the circuit by replacing the lower delta 25

Part A Simplify the circuit by replacing the lower Δ (25 ohm, r 2 = 57.5 ohm and 40 ohm) with its equivalent Y as shown in (Figure) . Determine the resistances of the equivalent Y. Express your answers using three signif ...

Suppose a clocked synchronous system uses registers with

Suppose a clocked synchronous system uses registers with setup time of 150ps and clock-to-output delay of 400ps. Three register-toregister paths in the datapath have propagation delays of 600ps, 900ps and 1.3ns, respecti ...

  • 4,153,160 Questions Asked
  • 13,132 Experts
  • 2,558,936 Questions Answered

Ask Experts for help!!

Looking for Assignment Help?

Start excelling in your Courses, Get help with Assignment

Write us your full requirement for evaluation and you will receive response within 20 minutes turnaround time.

Ask Now Help with Problems, Get a Best Answer

A cola-dispensing machine is set to dispense 9 ounces of

A cola-dispensing machine is set to dispense 9 ounces of cola per cup, with a standard deviation of 1.0 ounce. The manuf

What is marketingbullwhat is marketing think back to your

What is Marketing? • "What is marketing"? Think back to your impressions before you started this class versus how you

Question -your client david smith runs a small it

QUESTION - Your client, David Smith runs a small IT consulting business specialising in computer software and techno

Inspection of a random sample of 22 aircraft showed that 15

Inspection of a random sample of 22 aircraft showed that 15 needed repairs to fix a wiring problem that might compromise

Effective hrmquestionhow can an effective hrm system help

Effective HRM Question How can an effective HRM system help facilitate the achievement of an organization's strate