Question

Q3: (a) Determine the terminal voltage of a dc shunt generator which develops an e.m.f. of...

Q3: (a) Determine the terminal voltage of a dc shunt generator which develops an e.m.f. of 240V and has an armature current of 50 A on load. Assume the armature resistance is 0.04Ω. [3 marks]

(b) A lap wound armature is used in a 4-pole dc machine and 70 coils on the armature each containing 10 turns. The flux per pole in the machine is 40 mWb and the machine rotates at 500 rpm; (a) How many current paths are there in the machine, (b) What is its induced voltage (c) Find the emf per turn of the coil. [3 marks]

(c) (i)Draw the speed vs load curve of a dc shunt motor and a dc series motor [1 mark]

(ii) Draw torque vs load curve of a dc separately excited motor. [1 marks]

(iii) Why the demagnetization in a dc motor is more dangerous when compared to a dc generator? Note that the demagnetization occurs due to the armature reaction in a dc machine.

Engineering   Electrical-Engineering   
0 0
Add a commentTranscribed image text
Next >

Homework Answers

Answer #1

0 0
Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Log In

Sign Up

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
a)Explain the shunt excitation and compound excitation of DC generator. b)A 240V compound DC motor has...
a)Explain the shunt excitation and compound excitation of DC generator. b)A 240V compound DC motor has the armature, series field and shunt field resistances are 0.22 Ω, 0.04 Ω and 200 Ω respectively. On full load, the line current is 17.5 A and the motor runs at 1800 rpm. (short shunt) i) Draw the diagram and the power flow of the motor. ii) Find the back EMF of the motor. iii) Find the mechanical power developed. iv) Find the output...
1) A DC machine induces an EMF of 240 v at 1500 rpm. Find the developed...
1) A DC machine induces an EMF of 240 v at 1500 rpm. Find the developed torque for an armature current of 25A. 2) Draw and explain all characteristics of d.c. Shunt motor. 3) State accessitivity of 3 point starter. 4) A four pole wave connected dc armature has 50 slots with 10 conductors per slot. The armature is rotated at 1000 rpm of the useful flux per pole is 30mwb, calculate the amount of EMF induced. 5) A 6...
A 25-hp, 240V, DC shunt motor has armature and field resistances of 0.2 ? and 120...
A 25-hp, 240V, DC shunt motor has armature and field resistances of 0.2 ? and 120 ?, respectively. At no load and rated voltage, the motor draws a line current of 5A and its speed is 1250 rpm. When driving a certain load, the input to the motor is 15KW. For this condition, find: a.The speed of the motor b.The developed torque The efficiency of the motor at this load
The full-load armature current of a 5 hp, 150 V shunt dc motor is 30 A....
The full-load armature current of a 5 hp, 150 V shunt dc motor is 30 A. The field (shunt) resistance and the armature resistance of the motor are ????F = 125 ? and ???????? = 0.15, respectively. At a random speed of 1800 rpm magnetization curve of the motor has measured and is shown in the table below. ????0 (V) armature voltage 10 90 110 140 170 185 ???????? (A) field (shunt) current 0 0.82 1 1.2 1.7 2.88 Calculate...
Question 2 The full-load armature current of a 5 hp, 150 V shunt dc motor is...
Question 2 The full-load armature current of a 5 hp, 150 V shunt dc motor is 30 A. The field (shunt) resistance and the armature resistance of the motor are ????F=125 ? and ????????=0.15, respectively. At a random speed of 1800 rpm magnetization curve of the motor has measured and is shown in the table below. EO(V) armature voltage 10 90 110 140 170 185 IF (A) field (shunt) current 0 0.82 1 1.2 1.7 2.88 Calculate the following: a....
A 200 V DC, 1,800 RPM shunt connected motor has an armature resistance of 0.4 ohm...
A 200 V DC, 1,800 RPM shunt connected motor has an armature resistance of 0.4 ohm and a brush resistance of 0.4 ohm; brush voltage drop of 6.0 V, independent of load. The resistance of the shunt field is 230 ohm. The full load rated line current is 40 A. When the motor is operated at no load the line current is 5 A and the speed is 1750 RPM. Calculate speed at rated load Calculate speed at .3 rated...
A shunt-wound DC motor with the field coils and rotor connected in parallel (see the figure)...
A shunt-wound DC motor with the field coils and rotor connected in parallel (see the figure) (Figure 1)operates from a 130 VV DC power line. The resistance of the field windings, RfRfR_f, is 201 ΩΩ . The resistance of the rotor, RrRrR_r, is 4.10 ΩΩ . When the motor is running, the rotor develops an emf EEEMF. The motor draws a current of 4.88 AA from the line. Friction losses amount to 47.0 WW . a) Compute the field current...
Q.1: Choose the correct answer (and expalin) for the follwoings: Minimum number of coils for 400...
Q.1: Choose the correct answer (and expalin) for the follwoings: Minimum number of coils for 400 V, 6-pole lap connected de machine for a maximum voltage of 15 V between adjacent commutator segments should be (a) 80 (b) 160 (c) 200 (d) 400 The armature resistance of a 6-pole lapp wound de machine is 0.05 Q. If the aramture is re-wound using a wave winding, then the armature resistance will be (a) 0.452 (b) 0.30 (c) 0.15 (d) 0.102 A...
ADVERTISEMENT
Need Online Homework Help?

Get Answers For Free
Most questions answered within 1 hours.

Ask a Question
ADVERTISEMENT