EE 414 – Energy Conversion 1 Prelim Examination Name: ______________________________________________________ Rating : ____________ Test I. Multiple Choice. Select the correct answer. 1. Find the armature current of dc shunt generator whose shunt field current is 40 A and load circuit of 400 A. a) 380 A b) 400 A c) 420 A d) 440 A 2. A 4-pole dc generator with duplex wave winding has 48 slot and four elements per slot. The flux per pole is 2.5 x 10 6 maxwells and it runs at 1500 rpm. What is the output voltage? a) 60 V b) 120 V c) 225 V d) 360 V 3. Which of the following is not a requirements for successful parallel operation of generators. a) Same polarity b) Same voltage c) Same internal characteristics d) As much as possible same speed droop characteristics. 4. In a 12-pole duplex wave wound dc armature, each conductor can carry a current of 50 amperes. What is the rated current of the armature? a) 200 A b) 600 A c) 1200 A d) 2400 A 5. If the armature of an eight-pole machine were wound with a triplex wave winding, how many parallel paths would there be? a) 24 paths b) 16 paths c) 12 paths d) 6 paths 6. The generated emf in a dc generator is directly proportional to a) flux b) speed c) parallel paths d) both a & b 7. A 2-pole duplex-lap dc machine has 400 conductors in its armature and is driven at 300-rpm. Calculate the generated EMF if the flux is 0.1 Wb. a) 100 V b) 200 V c) 300 V d) 400 V 8. If each conductor of an 8-pole simplex-lap armature winding can carry a current of 100-A. Calculate the current capacity of this machine. a) 200 A b) 400 A c) 800 A d) 1600 A 9. A shunt generator delivers a load current of 500 A at a terminal voltage of 230 V. If the shunt field resistance and armature resistance are 50-Ω and 0.02-Ω respectively, calculate the armature’s generated emf. a) 225 V b) 230 V c) 235 V d) 240 V 10. A generator with 1.6 Ω armature circuit resistance has a terminal voltage of 125 V when the armature current is 8 A. Assuming that the generated voltage does not change, find the terminal voltage when the armature current is 18 A. a) 104.0 V b) 109.0 V c) 132.8 V d) 137.8 V Test II. Problem Solving. Show your solution. 1. In a short compound generator, the terminal voltage is 230 V when generator delivers a 150 A. Determine a) Induced (generated) emf , b) total power generated and c) Power delivered. Given that the shunt field, series field, diverter and armature resistances are 92 Ω, 0.015 Ω, 0.03 Ω and 0.032 Ω resp