...5.7 Necessity of D.C. Motor Starter At starting, when the motor is stationary, there is no back e.m.f. in the armature. Consequently, if the motor is directly switched on to the mains, the armature will draw a heavy current (Ia = V/Ra) because of small armature resistance. As an example, 5 H.P., 220 V shunt motor has a full-load current of 20 A and an armature resistance of about 0.5 . If this motor is directly switched on to supply, it would take an armature current of 220/0.5 = 440 A which is 22 times the full-load current. This high starting current may result in: (i) burning of armature due to excessive heating effect, (ii) damaging the commutator and brushes due to heavy sparking, (iii) excessive voltage drop in the line to which the motor is connected. The result is that the operation of other appliances connected to the line may be impaired and in particular cases, they may refuse to work. In order to avoid excessive current at starting, a variable resistance (known as starting resistance) is inserted in series with the armature circuit. This resistance is gradually reduced as the motor gains speed (and hence Eb increases) and eventually it is cut out completely when the motor has attained full speed. The value of starting resistance is generally such that starting current is limited to 1.25 to 2 times the full-load current. 5.8 Types of D.C. Motor Starters The stalling operation of a d.c. motor consists in the insertion of external resistance into...
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...Queensland University of Technology Electrical – ENB103 – Assessment 1 DC Electrical Circuit Analysis – Part A Name: Student Num. Due Date: Table of Contents Introduction 3 1.0 Mesh Analysis 4 1.1 Determining mesh currents 4 1.2 Determining Nodal Voltage 5 1.2.1 Node A 5 1.2.2 Node B 6 2.0 Thevenin’s Theorem 6 2.1 Application of Thevenin’s Theorem 6 3.0 Comparing and Analysis of Results 9 3.1 Results 9 3.2 Analysis 9 Introduction The purpose of this assignment is to analyse a DC circuit provided and ascertain certain properties within the circuit. To do this will require the application of Mesh Analysis, Thevenin’s Theorem and simple DC Theory... 1.0 Mesh Analysis Applying mesh analysis to the circuit will determine the currents that flow through each of the three meshes provided. From these current values, simple DC theorem will be applied using Ohm’s law in order to calculate the voltage of node A and node B with respect to the ground node. 1.1 Determining mesh currents The following steps will outline what will be required to calculate mesh 1, 2 and 3 currents. 1. Observing the circuit, use Kirchhoff’s voltage rule to determine each mesh into a formula resulting in three separate formulas. Mesh 1 20(i1-2) + 20(i1-i3) + 50(i1-i2) = 0 90i1 - 50i2 - 20i3 = 40 Mesh 2 50(i2-i1) + 25i2 + 26 = 0 -50i1 + 75i2 = -26 Mesh 3 30i3 – 25 + 20(i3-i1) = 0 -20i1 + 50i3 = 25 2. Once completed simplify each formula by dividing...
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...with instructor-run demos. Assignments include the use of circuit analysis computer software. Course Goals: Upon successful completion of this course, students should be able to do the following: 1. analyze passive electric circuits to predict their behavior; 2. identify, analyze, and solve technical problems in linear systems; and 3. use state-of-the-art technology to solve problems in linear systems. Measurable Course Performance Objectives (MPOs): Upon successful completion of this course, students should specifically be able to do the following: 1. Analyze passive electric circuits to predict their behavior: 1. use mesh analysis to calculate the voltages and currents in a circuit with two or more voltage sources; 2. use nodal analysis to calculate the voltages and currents in a circuit with two or more current sources; 3. calculate and graph the transient response (to a...
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...Part I INTRODUCTION 1.1 Theories/Concept of the Design Class Volume Monitoring System with Automatic Influx Adjustment is a reliable circuit that takes over the task of counting the number of individuals inside a room very accurately. When somebody enters the room, the counter is incremented by one. When somebody exits the room, the counter will count down by one. The total number of individuals inside the room is displayed on the two 7-segments. Individual Counting is simply a measurement of the individual traffic entering and exiting offices, malls, sports, venues, rooms etc. Counting the number of individuals helps to maximize the efficiency and effectiveness of employees, floor area of an organization, and even the monitoring of the people inside. Individual counting is not limited to the entry or exit point of an establishment but has a wide range of applications that provide information to management on the volume and flow of people throughout a location. A common method for counting the visitors involves sharing human auditors to manually tally the number of individuals who pass by a certain location. But human-based data collection comes at great expense. Our project aims to automate the counting of individuals with the use of a detector called Light-Dependent Resistor which makes it more reliable and efficient. The use of human auditors is redirected to other functions which makes a more productive system. Another feature of this project is...
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...comprising of a BJT and resistors and measure the circuit voltages between emitter, common, base, and collector. • To theoretically calculate and verify the circuit using Ohm’s Law, KCL and KVL. • Determine the voltage drop across the collector load resistance and measure the current passing through the emitter and collector resistors. 1. Equipment and Parts List Equipment: • IBM PC or compatible • DMM (digital multimeter) • Variable dc power supply Parts: Qty. Component Tolerance Band Wattage Rating, W 1 2N3904 Transistor 6 10 K Ω Resistor gold ¼ 1 Proto Board Hookup wires of different colors Software: MultiSim III. Procedure 1. Theoretical Analysis 1. Given the circuit in Figure 1, calculate the total resistance between the base and VCC in kΩ and the total collector resistance (combination of R3 and R4) in kΩ. Enter the values obtained in Table 1 on the worksheet. Figure 1 2. Given Figure 1, calculate the circuit voltages cited below entering the values in Table 2 on the worksheet. Voltages VCC Emitter to common Base to common Collector to common Base to emitter Collector to emitter 3. If resistor R2 is removed from the base circuit, calculate the circuit resistances and voltages cited below and enter the values in Tables 3 and 4 respectively on the worksheet. Resistances (KΩ) Base and +VCC Total Collector Resistance Voltages (V)...
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...comprising of a BJT and resistors and measure the circuit voltages between emitter, common, base, and collector. • To theoretically calculate and verify the circuit using Ohm’s Law, KCL and KVL. • Determine the voltage drop across the collector load resistance and measure the current passing through the emitter and collector resistors. 1. Equipment and Parts List Equipment: • IBM PC or compatible • DMM (digital multimeter) • Variable dc power supply Parts: Qty. Component Tolerance Band Wattage Rating, W 1 2N3904 Transistor 6 10 K Ω Resistor gold ¼ 1 Proto Board Hookup wires of different colors Software: MultiSim III. Procedure 1. Theoretical Analysis 1. Given the circuit in Figure 1, calculate the total resistance between the base and VCC in kΩ and the total collector resistance (combination of R3 and R4) in kΩ. Enter the values obtained in Table 1 on the worksheet. Figure 1 2. Given Figure 1, calculate the circuit voltages cited below entering the values in Table 2 on the worksheet. Voltages VCC Emitter to common Base to common Collector to common Base to emitter Collector to emitter 3. If resistor R2 is removed from the base circuit, calculate the circuit resistances and voltages cited below and enter the values in Tables 3 and 4 respectively on the worksheet. Resistances (KΩ) Base and +VCC Total Collector Resistance Voltages (V)...
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...because they need to know that there is more than one way to check for voltage drops and find an open circuit. This article would be good for a beginner in electrical diagnostics along with a more advanced automotive technician because the technician may have forgotten the alternate way to make your meter do the work for you. The alternate way to make your meter do the work for you is so simple that I should have been able to pick up on it before reading the article, though I hadn’t. If you are measuring voltage drops on individual loads and thusly looking for an open circuit through current movement then that is fine. However you do have to remember that the voltage drop has to be an actual “drop” from the original power applied (12V ish). “Subtracting the value you see at the input from what you saw across the battery terminals will tell you how much of your source voltage has been dropped before whatever is left appears at the load input” (Glassford, p.4). That just confuses me, and makes me think that it is going to be a hard way to figure out something that I should just know how to do. The alternate way, and easier way is to put the voltmeter positive lead on the positive battery terminal and the negative lead on the input directly before the load you want to measure. In doing this you have cut out the actual math and made the meter do the math for you. This will tell you what the difference in voltage is between the two probes. If your meter leads are to short to do this...
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...ANALYSIS OF CIRCUIT (EE001-3-1) Instructions: • This assignment is to be carried out individually Learning Outcomes ON COMPLETION OF THE MODULE YOU SHOULD BE ABLE TO DEMONSTRATE THE FOLLOWING LEARNING OUTCOMES: | | |ABLE TO UNDERSTAND, AND BE ABLE TO APPLY BOTH ANALYSIS AND DESIGN THE OVERALL PROCESS OF DESIGN, INCLUDING MODELING AND COMPONENT | |DESCRIPTION. | | | |ABLE TO UNDERSTAND PASSIVE AND ACTIVE COMPONENTS. | | | |ABLE TO UNDERSTAND AND APPLY KIRCHHOFF’S LAWS, NODAL AND MESH ANALYSIS. | | | |ABLE TO UNDERSTAND THE OPERATION AND APPLICATIONS OF OPERATIONAL AMPLIFIER. | | ...
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...Node Voltage Analysis (NVA) applicable to linear networks NVA gives you a process for obtaining n equations in n unknowns. The unknowns are the node voltages. Once you have the node voltages, you can find any voltage or current anywhere in the circuit. Process: (Note the key words to remember each step.) 1. Draw Draw the circuit diagram indicating all element and source values. 2. Label Label a reference node, usually ground or a node with the most branches. Then label a node voltage for all the other nodes in the circuit. You must recall the definition of a node voltage: It is the voltage of the node with respect to the reference node. It is not the same thing as the voltage across a branch. In general, the voltage across a branch between nodes 1 and 2will be the difference of the two node voltages on either side: v12 = v1 – v2 3. Dependant Write the controlling quantity of any dependant source in terms of node voltages. You will need to look for the controlling quantity in the circuit to do this. 4. Super Identify all the supernodes. Then write the voltage of the source inside the supernode in terms of the node voltages on either side. You must recall the definition of a supernode: It is any voltage source with the two nodes on either side of it considered as one big node. Note: Any equations that you get in this step will be part of the n equations. 5. Kirchoff Apply...
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...conditions (the currents and voltages). The challenge of formal circuit analysis is to derive the smallest set of simultaneous equations that completely define the operating characteristics of a circuit. In this lecture we will develop two very powerful methods for analyzing any circuit: The node method and the mesh method. These methods are based on the systematic application of Kirchhoff’s laws. We will explain the steps required to obtain the solution by considering the circuit example shown on Figure 1. R1 + Vs R3 R2 R4 _ Figure 1. A typical resistive circuit. The Node Method. A voltage is always defined as the potential difference between two points. When we talk about the voltage at a certain point of a circuit we imply that the measurement is performed between that point and some other point in the circuit. In most cases that other point is referred to as ground. The node method or the node voltage method, is a very powerful approach for circuit analysis and it is based on the application of KCL, KVL and Ohm’s law. The procedure for analyzing a circuit with the node method is based on the following steps. 1. Clearly label all circuit parameters and distinguish the unknown parameters from the known. 2. Identify all nodes of the circuit. 3. Select a node as the reference node also called the ground and assign to it a potential of 0 Volts. All other voltages in the circuit are measured with respect to the reference node. 4. Label the voltages at all other nodes. 5....
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...electrical circuit. These relationships are determined by some basic laws which are known as Kirchhoff laws or more specifically Kirchhoff Current and Voltage laws. These laws are very helpful in determining the equivalent electrical resistance or impedance of a complex network and the currents flowing in the various branches of the network. These laws are first derived by Guatov Robert Kirchhoff and hence these laws are also referred as Kirchhoff Laws. We saw in the Resistors tutorial that a single equivalent resistance, ( RT ) can be found when two or more resistors are connected together in either series, parallel or combinations of both, and that these circuits obey Ohm’s Law. Sometimes in complex circuits such as bridge or T networks, we cannot simply use Ohm’s Law alone to find the voltages or currents circulating within the circuit. For these types of calculations we need certain rules which allow us to obtain the circuit equations and for this we can use Kirchhoff’s Circuit Law. These two rules are commonly known as: Kirchhoff’s Circuit Laws with one of Kirchhoff’s laws dealing with the current flowing around a closed circuit, Kirchhoff’s Current Law, (KCL) while the other law deals with the voltage sources present in a closed circuit, Kirchhoff’s Voltage Law, (KVL). Kirchhoff’s Current Law is the 3 currents entering the node, I1, I2, I3 are all positive in value and the 2 currents leaving the node, I4 and I5 are negative in value. The term Node in an electrical circuit...
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...Physics 122 Lab 7: Circuits II Abstract: The main objective of this experiment was to test and verify Kirchhoff’s two rules: the loop rule and junction rule in a complex circuit. The voltage and current of each of the six resistors in the circuit were measured using a DMM. These values were then used to calculate the resistance of each resistor. The calculated resistor values were compared to the measured DMM values and the nominal values. By doing so, Ohm’s Law was proved because the values were consistent. The second part of the experiment involved using the current and voltage values obtained in part 1 to prove Kirchhoff’s loop and junction rule. The results, although were not zero, complied with Kirchhoff’s two rules within experimental error supporting Kirchoff’s rules regarding the voltage and circuit in a closed DC circuit. Ruby Bahniwal Partner: Jesse Olson 2011-07-25 T.A. Ali Introduction: The purpose of this experiment was to learn how to assemble a circuit properly, Figure 1 below, using the equipment provided and to experimentally verify Kirchhoff’s rules by measuring the voltage or potential drop across each resistor along with the current for each branch in the circuit constructed. Electric circuits have the ability to direct and control the flow of electricity and the energy conveyed. It can be constructed using various combinations of batteries, resistors and capacitors. These circuits are found in common...
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...11 Lab Final: Voltage Regulator with Constant Current Limiting (PORTFOLIO) Scope and Intention of the Project: The Lab Final Project is a self-directed project with specific requirements provided. You will be given a design task which utilizes a standard circuit in the textbook. You will apply knowledge that has been acquired in lecture, assignments, and previous labs. Task: Your task is to design, simulate, build and test a voltage regulator with constant current limiting as shown in Fig. 11-7 on page 559, Chapter 12 in the textbook. In addition to providing a circuit which operates to the specified functionality, you will submit a project report with required format and contents. D1 D1 This circuit is to be built according to the following specifications: * Input Voltage Range: + 9 V DC to +15 V DC * Q1 and Q2: 2N3904 Transistor * D1: 1N4733 Zener Diode * R1 = 1.0 kΩ, R2 = 10 kΩ, R3 = 10 kΩ, R4 = 1.0 Ω * Nominal Output Voltage: + 10 V DC * Max. Output Current: 500 mA Required Test Data: 1. Line regulation for input voltage changes from +9 V to +15 V 2. Load regulation for load changes from open circuit to 1000 Ohm load resistance 3. Graph of output voltages for at least 5 different input voltages, using a 150 Ohm load resistor 4. (Y-axis scaled for output voltage, x-axis scaled for resistive load) 5. Graph of output voltages for at least 5 different loads (include “no load”) at 12 V input voltage 6. (Y-axis...
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...Where V represents Voltage drop, I represents Current, R represents Resistance, & P represents Power lost. This intro tells me that I will be using a plant voltage of 120V to solve the first cases. I can see that I’ll be predicting various voltage drops across a completed circuit, from a power plant to a house. Exercise 5A, Case 2 If nothing is hooked up in the house: 1.) What is the current through the supply wire? To solve this I go back to my equation, deciding to use I=V/R , but thinking back on the intro I see there is nothing hooked up in the house; therefore, there is no current. The answer is 0. 2.) What is the voltage drop along the supply wire? To solve you would use the equation V=IR, I is 0; therefore, the voltage drop will also be 0. 3.) What is the amount of power converted to thermal energy (Power loss)? To solve this one, P=IV, I and V are both 0; therefore no power is lost in this Case. My predicted answers were correct in this case. If there is nothing in the house, then no current is flowing through the wires. Exercise 5A, Case 3 Now I’m asked that if I’m using super conducting wires with 0 electrical resistance and we plug in a 100 Watt lamp inside the house: 1.) What is the current through the circuit? I=P/V (100 watts)/(120 volts)= 0.83 Amps 2.) What is the resistance of the lamp? R=V/I (120 volts)/(0.83 amps)= 144.6 Ohms 3.) What is the voltage drop across the lamp? 120 volts 4.) What is the voltage drop across the supply...
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...number will hand in a complete lab report for all odd numbered labs (LABS 1, 3, 5, 7, 9). Students assigned an even number will hand in a complete lab report for all even numbered labs (LABS 2, 4, 6, 8, 10). 7. Upon completion of lab, make sure that the professor reviews and signs off on the lab cover page. If the lab is not signed by the professor or lab supervisor, a grade of “Zero” will be assigned. Professor’s Ack. ________________________________________________ Professor: L. Forte; MA Ed., P. Eng. EMNG 1001 – Circuit Analysis Lab Page 1 Objectives 1. Develop familiarity with Multisim Simulation software. 2. Use Multisim to simulate, analyze and solve a complex combination circuit. 3. Use Multisim to take current and voltage measurements. Procedure 1) Use the Multisim Simulation Software Program to construct the circuit...
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