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Q81HardRectifiers & Converters

एक सिंगल-फेज़ फुल कन्वर्टर 230 V, 50 Hz से जुड़ा है। लोड R = 10 Ω के साथ बहुत बड़ा प्रेरकत्व है। α = 30° के लिए सत्यापित कीजिए।
1. औसत आउटपुट वोल्टेज लगभग 179.3 V है।
2. इनपुट धारा का RMS मान 17.93 A है।
3. मूल पावर फैक्टर 0.866 है।
कौन-से कथन सही हैं?

उत्तर और चरणबद्ध हल
सही उत्तर: C. 1, 2 और 3
संक्षिप्त व्याख्या

C — 1, 2 और 3। Vdc = (2√2×230/π)cos30° ≈ 179.3 V; बड़े प्रेरकत्व से Id ≈ 17.93 A और स्क्वेयर-वेव इनपुट धारा का RMS = Id = 17.93 A; मूल विस्थापन गुणांक = cos30° = 0.866।

विस्तृत हल (मूल भाषा में)

Statement-wise Verification

  • Statement 1 - Correct.
    Average output voltage is approximately 179.3 V.
    Vdc=(2√2×230/π)cos30°≈179.3 V.
  • Statement 2 - Correct.
    The RMS value of the input current is 17.93 A.
    With R=10 Ω and highly inductive continuous current, Id≈17.93 A.
  • Statement 3 - Correct.
    The fundamental power factor is 0.866.
    The fundamental displacement factor is cos30°≈0.866.

Core Concept

A fully controlled bridge feeding a highly inductive load operates with nearly continuous DC current. Firing angle controls average DC voltage; the AC-side current is non-sinusoidal and its fundamental is displaced approximately by α. In three-phase bridges each thyristor conducts for 120 electrical degrees under continuous current.

Formula / Key Relationship

1φ: Vdc=(2Vm/π)cosα≈0.9Vrms cosα; 3φ: Vdc≈1.35V_LL cosα.

Step-by-Step Check

Vdc=(2√2×230/π)cos30°≈179.3 V. With R=10 Ω and highly inductive continuous current, Id≈17.93 A. The fundamental displacement factor is cos30°≈0.866.

Why the Other Options Are Wrong

Option A is incorrect because it omits correct statement(s) 3. Option B is incorrect because it omits correct statement(s) 1. Option D is incorrect because it omits correct statement(s) 2.

Exam Shortcut / Approach

Large load inductance → nearly constant DC current.

Common Mistake

Distinguish displacement factor cosα from total power factor including distortion.

Quick Revision

Average Output and Input Current is linked with Single-Phase Full Converter, Controlled Rectifiers and Power Electronics. Large load inductance → nearly constant DC current.

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