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Q76ModerateRectifiers & Converters

સિંગલ-ફેઝ રેક્ટિફાયરમાં સ્રોત પ્રેરકત્વ (Ls)ની અસર અંગે:
1. તે કોણ μ દ્વારા દર્શાવાતો "કમ્યુટેશન ઓવરલેપ" ઉત્પન્ન કરે છે.
2. તે સરેરાશ આઉટપુટ વોલ્ટેજ ઘટાડે છે.
3. ઓવરલેપ દરમિયાન આઉટપુટ વોલ્ટેજ બંને કમ્યુટેટિંગ ફેઝના સરેરાશને અનુસરે છે.
ઉપર આપેલાં કયાં વિધાનો સાચાં છે?

જવાબ અને પગલાવાર ઉકેલ
સાચો જવાબ: B. ફક્ત 1, 2 અને 3
ટૂંકી સમજૂતી

B — 1, 2 અને 3. સ્રોત પ્રેરકત્વને કારણે પ્રવાહ ડિવાઇસ વચ્ચે તરત સ્થાનાંતરિત થતો નથી; ઓવરલેપ કોણ μ માં બંને ડિવાઇસ સાથે વહન કરે છે, આઉટપુટ બંને ફેઝના સરેરાશ પર રહે છે અને સરેરાશ DC વોલ્ટેજ ઘટે છે.

વિગતવાર ઉકેલ (મૂળ ભાષામાં)

Statement-wise Verification

  • Statement 1 - Correct.
    It causes a "commutation overlap" denoted by angle μ.
    Overlap introduces a commutation reactance drop; Vdc_actual < ideal Vdc.
  • Statement 2 - Correct.
    It reduces the average output voltage.
    During the overlap angle μ, outgoing and incoming devices conduct simultaneously, reducing average DC output voltage.
  • Statement 3 - Correct.
    During overlap, the output voltage follows the average of the two commutating phases.
    During the overlap angle μ, outgoing and incoming devices conduct simultaneously, reducing average DC output voltage.

Core Concept

Source inductance prevents current from transferring instantaneously between rectifier devices. During the overlap angle μ, outgoing and incoming devices conduct simultaneously, reducing average DC output voltage. The exact overlap voltage waveform depends on converter topology and the commutating source voltages.

Formula / Key Relationship

Overlap introduces a commutation reactance drop; Vdc_actual < ideal Vdc.

Why the Other Options Are Wrong

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

Exam Shortcut / Approach

More source inductance/current → more overlap.

Common Mistake

Ignoring source inductance overestimates rectifier DC output.

Quick Revision

Source Inductance Effect is linked with Commutation Overlap, Controlled Rectifiers and Power Electronics. More source inductance/current → more overlap.

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