Consider the following statements regarding DC Generators:
1. The generated EMF in a DC generator is directly proportional to both the speed of rotation and the magnetic flux per pole.
2. The field flux in a DC generator can be controlled by adjusting the field current in the excitation winding.
3. Armature reaction in a DC generator leads to distortion and weakening of the main magnetic field.
4. The commutator converts the internally generated alternating voltage into a unidirectional output voltage.
Which of the above statements is/are correct?
Answer & step-by-step solution
The generated EMF of a DC machine is proportional to flux per pole and speed. Field flux is controlled by excitation current, armature reaction distorts/weakens the main field, and the commutator provides mechanical rectification so the external generated voltage is unidirectional. Key relation: E_g=PΦZN/(60A).
Exam focus: Remember A=2 for wave winding and A=P for simplex lap winding. Common trap: Do not swap the parallel-path counts for lap and wave windings.
Statement-wise Verification
- Statement 1 - Correct.
The generated EMF in a DC generator is directly proportional to both the speed of rotation and the magnetic flux per pole.
The generated EMF of a DC machine is proportional to flux per pole and speed. - Statement 2 - Correct.
The field flux in a DC generator can be controlled by adjusting the field current in the excitation winding.
Field flux is controlled by excitation current, armature reaction distorts/weakens the main field, and the commutator provides mechanical rectification so the external generated voltage is unidirectional. - Statement 3 - Correct.
Armature reaction in a DC generator leads to distortion and weakening of the main magnetic field.
Field flux is controlled by excitation current, armature reaction distorts/weakens the main field, and the commutator provides mechanical rectification so the external generated voltage is unidirectional. - Statement 4 - Correct.
The commutator converts the internally generated alternating voltage into a unidirectional output voltage.
Field flux is controlled by excitation current, armature reaction distorts/weakens the main field, and the commutator provides mechanical rectification so the external generated voltage is unidirectional.
Core Concept
The generated EMF of a DC machine is proportional to flux per pole and speed. Field flux is controlled by excitation current, armature reaction distorts/weakens the main field, and the commutator provides mechanical rectification so the external generated voltage is unidirectional.
Formula / Key Relationship
E_g=PΦZN/(60A).
Why the Other Options Are Wrong
Option A is incorrect because it omits correct statement(s) 4. Option C is incorrect because it omits correct statement(s) 1, 3. Option D is incorrect because it omits correct statement(s) 2, 3.
Exam Shortcut / Approach
Remember A=2 for wave winding and A=P for simplex lap winding.
Common Mistake
Do not swap the parallel-path counts for lap and wave windings.
Quick Revision
Generated EMF Armature Reaction and Commutator is linked with DC Generator, DC Machines and Electrical Machines. Remember A=2 for wave winding and A=P for simplex lap winding.
DC जनरेटर के संबंध में निम्नलिखित कथनों पर विचार कीजिए:
1. DC जनरेटर में उत्पन्न EMF घूर्णन गति और प्रति पोल चुंबकीय फ्लक्स दोनों के समानुपाती है।
2. उत्तेजन वाइंडिंग में फील्ड करंट समायोजित कर DC जनरेटर का फील्ड फ्लक्स नियंत्रित किया जा सकता है।
3. DC जनरेटर में आर्मेचर रिएक्शन मुख्य चुंबकीय क्षेत्र को विकृत और कमज़ोर करता है।
4. कम्यूटेटर आंतरिक रूप से उत्पन्न प्रत्यावर्ती वोल्टेज को एकदिशीय आउटपुट वोल्टेज में बदलता है।
उपरोक्त में से कौन-सा/से कथन सही है/हैं?
उत्तर और चरणबद्ध हल
DC मशीन का उत्पन्न EMF प्रति पोल फ्लक्स और गति के समानुपाती है। फील्ड फ्लक्स उत्तेजन करंट से नियंत्रित होता है, आर्मेचर रिएक्शन मुख्य क्षेत्र को विकृत/कमज़ोर करता है और कम्यूटेटर यांत्रिक दिष्टकरण करता है। मुख्य संबंध: E_g=PΦZN/(60A)।
परीक्षा फोकस: वेव वाइंडिंग में A=2, सिम्प्लेक्स लैप में A=P।
विस्तृत हल (मूल भाषा में)
Statement-wise Verification
- Statement 1 - Correct.
The generated EMF in a DC generator is directly proportional to both the speed of rotation and the magnetic flux per pole.
The generated EMF of a DC machine is proportional to flux per pole and speed. - Statement 2 - Correct.
The field flux in a DC generator can be controlled by adjusting the field current in the excitation winding.
Field flux is controlled by excitation current, armature reaction distorts/weakens the main field, and the commutator provides mechanical rectification so the external generated voltage is unidirectional. - Statement 3 - Correct.
Armature reaction in a DC generator leads to distortion and weakening of the main magnetic field.
Field flux is controlled by excitation current, armature reaction distorts/weakens the main field, and the commutator provides mechanical rectification so the external generated voltage is unidirectional. - Statement 4 - Correct.
The commutator converts the internally generated alternating voltage into a unidirectional output voltage.
Field flux is controlled by excitation current, armature reaction distorts/weakens the main field, and the commutator provides mechanical rectification so the external generated voltage is unidirectional.
Core Concept
The generated EMF of a DC machine is proportional to flux per pole and speed. Field flux is controlled by excitation current, armature reaction distorts/weakens the main field, and the commutator provides mechanical rectification so the external generated voltage is unidirectional.
Formula / Key Relationship
E_g=PΦZN/(60A).
Why the Other Options Are Wrong
Option A is incorrect because it omits correct statement(s) 4. Option C is incorrect because it omits correct statement(s) 1, 3. Option D is incorrect because it omits correct statement(s) 2, 3.
Exam Shortcut / Approach
Remember A=2 for wave winding and A=P for simplex lap winding.
Common Mistake
Do not swap the parallel-path counts for lap and wave windings.
Quick Revision
Generated EMF Armature Reaction and Commutator is linked with DC Generator, DC Machines and Electrical Machines. Remember A=2 for wave winding and A=P for simplex lap winding.
DC જનરેટર સંબંધિત નીચેના વિધાનો ધ્યાનમાં લો:
1. DC જનરેટરમાં ઉત્પન્ન EMF ભ્રમણ ઝડપ અને પ્રતિ પોલ ચુંબકીય ફ્લક્સ બંનેના સમપ્રમાણમાં છે.
2. ઉત્તેજન વાઇન્ડિંગમાં ફીલ્ડ કરંટ ગોઠવીને DC જનરેટરનું ફીલ્ડ ફ્લક્સ નિયંત્રિત કરી શકાય છે.
3. DC જનરેટરમાં આર્મેચર રિએક્શન મુખ્ય ચુંબકીય ક્ષેત્રને વિકૃત અને નબળું કરે છે.
4. કમ્યુટેટર આંતરિક રીતે ઉત્પન્ન પ્રત્યાવર્તી વોલ્ટેજને એકદિશીય આઉટપુટ વોલ્ટેજમાં ફેરવે છે.
ઉપરોક્તમાંથી કયું/કયા વિધાન સાચું/સાચા છે?
જવાબ અને પગલાવાર ઉકેલ
DC મશીનનું ઉત્પન્ન EMF પ્રતિ પોલ ફ્લક્સ અને ઝડપના સમપ્રમાણમાં છે. ફીલ્ડ ફ્લક્સ ઉત્તેજન કરંટથી નિયંત્રિત થાય છે, આર્મેચર રિએક્શન મુખ્ય ક્ષેત્રને વિકૃત/નબળું કરે છે અને કમ્યુટેટર યાંત્રિક દિષ્ટકરણ કરે છે. મુખ્ય સંબંધ: E_g=PΦZN/(60A).
પરીક્ષા મુદ્દો: વેવ વાઇન્ડિંગમાં A=2, સિમ્પ્લેક્સ લેપમાં A=P.
વિગતવાર ઉકેલ (મૂળ ભાષામાં)
Statement-wise Verification
- Statement 1 - Correct.
The generated EMF in a DC generator is directly proportional to both the speed of rotation and the magnetic flux per pole.
The generated EMF of a DC machine is proportional to flux per pole and speed. - Statement 2 - Correct.
The field flux in a DC generator can be controlled by adjusting the field current in the excitation winding.
Field flux is controlled by excitation current, armature reaction distorts/weakens the main field, and the commutator provides mechanical rectification so the external generated voltage is unidirectional. - Statement 3 - Correct.
Armature reaction in a DC generator leads to distortion and weakening of the main magnetic field.
Field flux is controlled by excitation current, armature reaction distorts/weakens the main field, and the commutator provides mechanical rectification so the external generated voltage is unidirectional. - Statement 4 - Correct.
The commutator converts the internally generated alternating voltage into a unidirectional output voltage.
Field flux is controlled by excitation current, armature reaction distorts/weakens the main field, and the commutator provides mechanical rectification so the external generated voltage is unidirectional.
Core Concept
The generated EMF of a DC machine is proportional to flux per pole and speed. Field flux is controlled by excitation current, armature reaction distorts/weakens the main field, and the commutator provides mechanical rectification so the external generated voltage is unidirectional.
Formula / Key Relationship
E_g=PΦZN/(60A).
Why the Other Options Are Wrong
Option A is incorrect because it omits correct statement(s) 4. Option C is incorrect because it omits correct statement(s) 1, 3. Option D is incorrect because it omits correct statement(s) 2, 3.
Exam Shortcut / Approach
Remember A=2 for wave winding and A=P for simplex lap winding.
Common Mistake
Do not swap the parallel-path counts for lap and wave windings.
Quick Revision
Generated EMF Armature Reaction and Commutator is linked with DC Generator, DC Machines and Electrical Machines. Remember A=2 for wave winding and A=P for simplex lap winding.
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