(B)- Indicate whether the following statements are true or false and correct the false statements 1-In d.c shunt motor the main advantage of rheostatic control method, the specd up to zero is possible 2 The imaginary component of no load current for transformer is responsible for the consumption of iron loss 3- The speed ofd.c series motor is decreased if the armature current is increased 4- The armature voltage of d.c series generator is not affected by load current S-The regulation at rated load of a transformer same at 0.8 pf lag and 0.8 pf lead

(B)- Indicate whether the following statements are true or false and correct the false statements 1-In d.c shunt motor the main advantage of rheostatic control method, the specd up to zero is possible 2 The imaginary component of no load current for transformer is responsible for the consumption of iron loss 3- The speed ofd.c series motor is decreased if the armature current is increased 4- The armature voltage of d.c series generator is not affected by load current S-The regulation at rated load of a transformer same at 0.8 pf lag and 0.8 pf lead

Delmar's Standard Textbook Of Electricity

7th Edition

ISBN:9781337900348

Author:Stephen L. Herman

Publisher:Stephen L. Herman

Chapter33: Single-phase Motors

Section: Chapter Questions

Problem 32RQ

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(B)-ndicate whether the following statements are true or false and correct the faise statements. -When a series d.c. motor is operate without load, the armature will not run. The strength of magnetic field in d.c. shunt generator can be varied by varying the polarity of the field poles The main disadvantage of series generators is Output voltage varies as the Toad varies There is no output from the transformer under short-circuit conditions
(3) The speed of the synchronous motor: a- Reduced linearly with the increase of load. b- Reduced in a non-linear manner with the increase of load. c- Remains the same with increase of load. (4) The flux density inside the transformer core: a- Reduced with the increase of load. b- Increased with the increase of load. c- Is constant with the increase of load.
vii. Why Induction motor is called rotating transformer?
15) Which of the following machine will have the field winding with low value of resistance. a. DC Shunt Motor b. DC Series Motor c. Transformer d. DC Shunt Generator
Q5. (A) Select the correct answer for the alternatives given 1-In transformer, the load current at maximum efficiency is equal to rated load current multiplied by a) Peu Pa Pru Pi 2- When a series de motor is operated without a load, which of the following conditions occur? b) The voltage requirement increases d) The armature speeds out of control a) The armature draws excessive current c) The armature will not turn P₁ d) Peu 3- A 220V shunt motor develops a torque of216 N.m at an armature current of 40 A. The torque developed when the armature current is 20 A b)108 N.m c) 864 N.m a) 432 N.m d) 54 N.m 4-A single phase transformer has maximum efficiency at 75% of full load. Its copper loss at full load should be a) equal to core loss, b) less than core loss. c) more than core loss, d) equal to 75% of core loss 5- The efficiency of a transformer is 98% at full-load with 0.8 lagging power factor, what will be the efficiency when supplies full-load with 0.8 leading power factor? c) more…
4. e principle of operation of a 3-phase. Induction motor is most similar to that of a (a) synchronous motor (b) DC motor (c) transformer with a shorted secondary (d) SPIM 5. 500 kW, 3-phase, 440 volts, 50 Hz, A.C. induction motor has a speed of 960 r.p.m. on full load. The machine has 6 poles. The slip of the machine will be (a) 0.01 (b) 0.02 (c) 0.03 (d)0.04 6. A centrifugal switch is used to disconnect 'starting winding when motor has (a) picked up about 50 to 75 per cent of rated speed (b) picked up about 10 to 15 per cent of rated speed (c) run for about 1 minute (d) run for about 5 minutes 7- A 6-pole, 50-Hz, 3-0 induction motor is running at 950 rpm and has rotor Cu loss of 6 kW. Its rotor input is......kW (a) 120 (b) 60 (c) 6.3 (d) 66 8- The number of slip rings on a squirrel cage induction motor is usually (a)Two (b) Three (c) Four (d) None
Q choose the correct answer: 1-Brushless excitation system consisting of.... a- Stator field winding and power diodes b-stator and rotor field winding and capacitor c- stator and rotor field winding and capacitor d- Everything mentioned in the options 2- Voltage generated per phase in an alternator is proportional to a- Flux per pole b- Number of turns in armature c-Winding factors d- Everything mentioned in the options e- Frequency of waveform 3- If input mech. Power of SG constant, the functionality of AVR is a- Control flux of rotor b-Control terminal voltage c- Control flux and terminal voltage d-Control Load angle
2- A 4-pole, wave-wound d.c. shunt generator has an armature winding consisting of 300 turns each of 0.0020. The armature resistance is a) 0.152 b)0.62 c) 0.30 d) none of above
(B)- Indicate whether the following statements are true or false and correct the false statements 1-In d.c shunt motor the main advantage of rheostatic control method, the speed up to zero is possible The imaginary component of no load current for transformer is responsible for the consumption of iron loss 3- The speed of d.c series motor is decreased if the armature current is increased 4- The armature voltage of d.c series generator is not affected by load current 5-The regulation at rated load of a transformer same at 0.8 pf lag and 0.8 pf lead tuo
4. What for brushes are employed in DC generator? 5. What is the function of armature in a DC generator? 6. What is the function of commutator in a DC machine in generator action. 7 Whieh diffe u0ad in
11 Which of the following machine will have the field winding with low value of resistance. a. Transformer b. DC Shunt Generator c. DC Series Motor d. DC Shunt Motor
Here it is the equivalent circuit of and induction motor and it is per phase circuit my question is name for me the variable for example R1 is the winding resistance and so an the all variable and please show me a pic of the real machine with the variable for example for R1 happens because of the winding i need to see the winding in the real machine, please help me to understand well