Delmar's Standard Textbook Of Electricity
7th Edition
ISBN: 9781337900348
Author: Stephen L. Herman
Publisher: Cengage Learning
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Chapter 27, Problem 5RQ
What is an autotransformer?
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Jalis 6
In d.c. generators armature reaction is produced by
field current O
armature current
commutating winding current
none of the mentioned
compensating winding current
*.The use of d.c. generators eliminated the use of rectifiers and ac supplies
True
False O
What is use of solenoid coil in the pressure to converter?
a. To produce magnetic field in the LVDT
b. To change the LVDT output
c. To bring back the pivoted beam normal position
d. To produce linear displacement in bellows
Pole machine.
Chapter 27 Solutions
Delmar's Standard Textbook Of Electricity
Ch. 27 - What is a transformer?Ch. 27 - What are common efficiencies for transformers?Ch. 27 - What is an isolation transformer?Ch. 27 - All values of a transformer are proportional to...Ch. 27 - What is an autotransformer?Ch. 27 - What is a disadvantage of an autotransformer?Ch. 27 - Explain the difference between a step-up and a...Ch. 27 - A transformer has a primary voltage of 240 V and a...Ch. 27 - A transformer has an output of 750 VA. The primary...Ch. 27 - A transformer has a turns ratio of 1:6. The...
Ch. 27 - What do the dots shown beside the terminal leads...Ch. 27 - A transformer has a primary voltage rating of 240...Ch. 27 - If the windings of the transformer in Question 12...Ch. 27 - The primary leads of a transformer are labeled 1...Ch. 27 - You are working in an industrial plant. You must...Ch. 27 - You have been given a transformer to install on a...Ch. 27 - EP120VIPNP300TurnsRatioEs24IsNsZ=3Ch. 27 - EP240VIPNPRatioEs320VIsNs280Z=500Ch. 27 - EPIPNPRatio1:2.5Es160VIsNs80TurnsZ=12Ch. 27 - Prob. 4PPCh. 27 - Prob. 5PPCh. 27 - ES480VIPNS275turnsRatioESISNS525turnsZ=1.2kCh. 27 - ...Ch. 27 - ...
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- What Is CNC Machining? How does it work?arrow_forward. Draw the circuit diagram for the four machine types that can be obtained from the DC shunt wound machine. Name each type. 1987 1408arrow_forward5. In relation to a compound d.c machine, choose the right statement from the following. (A) The resistance of the shunt field coil will be many times higher than the series field coil. (B) The resistance of the shunt field coil and the series field coil are of the same order. (C) The resistance of the series field coil will be many times higher than the shunt field coil. (D) Either of (A), (B) and (C) is true statement.arrow_forward
- 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…arrow_forwardA de machine is controlled by the step-down de-de converter shown below. The armature inductance La =0.2 mH and the armature resistance can be neglected. The armature current is 5A. The Buck converter is operating at the switching frequency is 30 kHz and the duty ratio is 0.8. L₁ + Answer the following questions: 1) Calculate the input voltage (Va) if the output voltage (ea = 200 V). 2) Find the ripple in the armature current (a). 3) Calculate the maximum and minimum values of the armature current (la). 4) Sketch the armature current (ia (t)) and the supply current (id (t)).arrow_forward← Introduction to Control... The maximum a transformer temperature rise of is 50°C. It attains a temperature 31.6° in 1/2 hour. What its thermal time constant?arrow_forward
- help me in these questions pls write the questions with the and by (Computer) 1-Which of the following statements INCORRECTLY explain the label in the figure about LVDT working principles? a. Secondary coils are connected in series in such a way that their output is opposing each other. b. Constant DC voltage input to primary coil. c. Displacement moves ferrous rod from central position. d. The difference of the output voltage between the two secondary voltage.==========2- Explain the working principle of the measurement system in the figure below.i. Force input that is supplied to the sensor is processed to give the response in the form of raw output signal.ii. Signal conditioner manipulated the weak signal to give a conditioned input.iii. Analog or digital indicator display the unit that gives output reading of quantity being measured.iv. Measured value is compared with the input value for further action. a. ii, iii and iv only. b. i, ii and iv only. c. i, ii and…arrow_forwardWhich of the following is preferred to counter the effect of armature reaction in DC machine? O Use of main pole OUse of interpoles Use of series winding O Shifting of brushesarrow_forward2- At no-load the power input to transformer equal to 3- The value of resistance between primary and secondary winding practically equal to 4- The power losses its difference between mechanical power and power developed in armature winding. 5- If the armature resistance Ra increases, the Emf will Q2: Correct the wrong statement if any: 1-The series filed of a series de generator is excited by armature current. 2- The developed power in DC generator armature is function to load current. 3-The commercial efficiency of DC generators is relationship between output mechanical power and developed power in armature winding. 4- If the source frequency subjected to primary windings inereased, the iron losses also decreased. 5-In transformers short circuit test primary voltage will be greater than secondary voltage. GOOD LUCKarrow_forward
- Draw the DC Machine and label its parts Example. Armature Winding Stator Pole Shoe/Face Field Winding Brush Armature Core Bearing Shaft Commutatorarrow_forward6. In relation to a compound d.c machine, choose the right statement from the following (A) Both series and shunt field coils have comparable and number of turns and cross sectional areas. (B) Shunt field coil has fewer number of turns and large cross sectional area compared to series field coil. (C) Series field coil has fewer number of turns and large cross sectional area compared to shunt field coil. (D) None of (A), (B) and (C) are correct statement.arrow_forwardA thicker wire is used in the DC series field winding than DC shunt field winding in DC machines. * O because it carries the load current. O to prevent mechanical vibrations. O to provide strength. O to produce large flux. The speed of a DC motor can be changed by varying - armature resistance circuit O flux per pole O voltage source O all of abovearrow_forward
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