DC Generator Efficiency MCQ Quiz in বাংলা - Objective Question with Answer for DC Generator Efficiency - বিনামূল্যে ডাউনলোড করুন [PDF]

Last updated on Apr 20, 2025

পাওয়া DC Generator Efficiency उत्तरे आणि तपशीलवार उपायांसह एकाधिक निवड प्रश्न (MCQ क्विझ). এই বিনামূল্যে ডাউনলোড করুন DC Generator Efficiency MCQ কুইজ পিডিএফ এবং আপনার আসন্ন পরীক্ষার জন্য প্রস্তুত করুন যেমন ব্যাঙ্কিং, এসএসসি, রেলওয়ে, ইউপিএসসি, রাজ্য পিএসসি।

Latest DC Generator Efficiency MCQ Objective Questions

Top DC Generator Efficiency MCQ Objective Questions

DC Generator Efficiency Question 1:

A 125 V, 12.5 kW shunt generator is driven by a 20hp motor to generate rated output. The armature circuit resistance is 0.1 Ω, and the field circuit resistance is 62.5 Ω. The rated variable electric loss is 1040 W. At rated power output, the armature current for maximum efficiency is__ (in A)

Answer (Detailed Solution Below) 117 - 118

DC Generator Efficiency Question 1 Detailed Solution

Shunt field loss,Vt2Rsh=125262.5=250W

Load current,IL=PoutVt=12500125=100A

Shunt field current,Ish=VtRsh=12562.5=2A

Armature current,Ia=IL+Ish=102A

Generated emf,Eg=Vt+IaRa=125+(102×0.1)=135.2V

Developed power,Pd=EgIa=135.2×102=13790.4W

Rotational losses,Pr=PinPd=(20×746)(13790.4)=1129.6W

The constant loss is,Pconst=Pr+VshIsh=1129.6+250=1379.6W

For maximum efficiency, armature current

Ia=PconstRa=1379.60.1=117.4A

DC Generator Efficiency Question 2:

A shunt generator delivers 160 A at terminal voltage of 220V. The armature resistance and shunt field resistance are 0.06 and 90 Ω respectively. The iron and friction losses are 700 W. What are mechanical, commercial and electrical efficiencies for generator respectively?

  1. 98.16%, 94.32%, 92.58%

  2. 92.58%, 98.16%, 94.32%

  3. 98.16%, 92.58%, 94.32%

  4. 94.32%, 98.16%, 92.58%

Answer (Detailed Solution Below)

Option 3 :

98.16%, 92.58%, 94.32%

DC Generator Efficiency Question 2 Detailed Solution

Current in shunt field, Ish=22090 

= 2.44 A

Armature emf, E = V + Iara

= 220 + (160 + 2.44) × 0.06   

= 229.75 V

Armature copper loss =Ia2ra

=(162.44)2×0.06

= 1583 W  

Shunt Cu loss = VIsh

= 220 × 2.44

= 536.8 W

Total cu loss = 2119.8 W

Stray losses = 700 W

Total losses = 2819.8 W  

o/P=VI=220×160

= 35200 W

I/P Provided by prime mover

= 35200 + 2819.8

= 38019.8 W

= Generator i/P

Electrical power produced in armature

= EgIa = 38019.8 – 700

= 37319.8 W

Mechanical Efficiency =εgIaPrime moverIP=37319.838019.8

= 0.9816

= 98.16%

Electrical efficiency =VIEgIa=3520037319.8

= 94.32%

Commercial efficiency =3520038019.8

= 92.58%

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