DC Distribution MCQ Quiz in मल्याळम - Objective Question with Answer for DC Distribution - സൗജന്യ PDF ഡൗൺലോഡ് ചെയ്യുക
Last updated on Mar 22, 2025
Latest DC Distribution MCQ Objective Questions
Top DC Distribution MCQ Objective Questions
DC Distribution Question 1:
In a 3-wire DC system, in order to maintain voltages on the two sides of the neutral equal to each other, a/an □( ) is used.
Answer (Detailed Solution Below)
DC Distribution Question 1 Detailed Solution
Explanation:
In a 3-wire DC system, maintaining balanced voltages on either side of the neutral is critical for efficient and stable operation. The device used to achieve this balance is known as a balancer set. Let’s delve deeper into the workings and importance of the balancer set and analyze why it is the correct choice among the options provided.
Balancer Set
Definition: A balancer set in a 3-wire DC system is a device designed to maintain the voltage levels on both sides of the neutral conductor equal. This is essential to ensure that the loads connected to the system receive a stable and balanced voltage, thereby preventing any potential damage or inefficiency in the electrical system.
Working Principle: The balancer set typically consists of two identical machines, usually DC generators or motors, connected in series across the supply voltage. The neutral point is taken from the junction between these two machines. When the system is balanced, the voltages on either side of the neutral are equal. If there is any imbalance due to unequal loading, the balancer set works to redistribute the voltages, ensuring that the voltage drop across each half remains equal.
Advantages:
- Ensures balanced voltages across the system, thereby enhancing the efficiency and lifespan of the electrical components connected to it.
- Helps in maintaining stable operation of the electrical system even under varying load conditions.
- Reduces the risk of electrical faults and potential damage to the system due to voltage imbalances.
Disadvantages:
- Additional complexity and cost due to the inclusion of the balancer set in the system.
- Requires regular maintenance to ensure proper operation and to avoid any potential faults.
Applications: Balancer sets are widely used in industrial and commercial settings where stable and balanced DC supply is critical. They are commonly found in systems with significant and variable loads, such as in manufacturing plants, data centers, and other facilities with sensitive electrical equipment.
Correct Option Analysis:
The correct option is:
Option 4: Balancer set
This option correctly identifies the device used in a 3-wire DC system to maintain balanced voltages on either side of the neutral. The balancer set ensures that the voltage levels remain equal, thereby promoting efficient and stable operation of the system.
Additional Information
To further understand the analysis, let’s evaluate the other options:
Option 1: Amplifier
An amplifier is an electronic device used to increase the power, voltage, or current of a signal. While amplifiers are critical in various electrical and electronic applications, they do not serve the purpose of maintaining balanced voltages in a 3-wire DC system. Therefore, this option is incorrect.
Option 2: Booster
A booster, in electrical terms, typically refers to a device used to increase the voltage level in a circuit. Although boosters are important in certain applications to ensure adequate voltage levels, they do not address the issue of balancing voltages on either side of the neutral in a 3-wire DC system.
Option 3: Diverter
A diverter is a device used to redirect the flow of current or voltage in a circuit. While it plays a role in managing electrical pathways, it is not specifically designed to maintain balanced voltages in a 3-wire DC system. Thus, this option is also incorrect.
Conclusion:
Understanding the role of a balancer set in a 3-wire DC system is crucial for maintaining efficient and stable operation. The balancer set ensures that the voltages on either side of the neutral are equal, preventing any imbalance that could lead to inefficiencies or damage. While other devices like amplifiers, boosters, and diverters have their specific applications, they do not fulfill the requirement of balancing voltages in this context.
DC Distribution Question 2:
A 2-wire dc street mains AB, 600 m long is fed from both ends at 220 V. Loads of 20 A, 40 A, 50 A, and 30 A are tapped at distances of 100 m, 250 m, 400 m, and 500 m from the end A respectively. The area of cross-section of distributor conductor is 1 cm2 and the resistivity is 1.7 × 10-6 Ω cm. The minimum consumer voltage is ________
Answer (Detailed Solution Below) 215 - 216
DC Distribution Question 2 Detailed Solution
The figure shows the distributor with tapped currents.
Let I amperes be the current supplied from the feeding end A.
Resistance of 1 m length of distributor \( = 2 \times \frac{{1.7 \times {{10}^{ - 6}} \times 100}}{1} = 3.4 \times {10^{ - 4}}{\rm{\Omega }}\)
Resistance of section AC, RAC = 3.4 × 10-4 × 100 = 0.034 Ω
Resistance of section CD, RAD = 3.4 × 10-4 × 150 = 0.051 Ω
Resistance of section DE, RDE = 3.4 × 10-4 × 150 = 0.051 Ω
Resistance of section EF, REF = 3.4 × 10-4 × 100 = 0.034 Ω
Resistance of section FB, RFB = 3.4 × 10-4 × 100 = 0.034 Ω
Voltage at A = voltage at B + voltage drop between A and B
⇒ 220 = 220 – [IRAC + (I – 20)RCD + (I – 60)RDE + (I – 110)REF + (I – 140)RFB]
⇒ 220 = 220 – [0.034I + (I – 20)0.051 + (I – 60)0.051 + (I – 110)0.034 + (I – 140)0.034]
⇒ I = 61.7 A
From the above diagram, the currents are coming to the load point E from both sides i.e. from point D and point F.
Hence, E is the point of minimum potential.
Minimum consumer voltage, VE = VA – [IACRAC + ICDRCD + IDERDE]
= 220 – [61.7 × 0.034 + 41.7 × 0.051 + 1.7 × 0.051]
= 215.69 V