Introduction to Alternating Current INTRODUCTION Much of the electrical energy used worldwide is produced by alternating-current (ac) generators. Such widespread use of alternating current means that students in electrical trades must understand the principles of electricity and magnetism and their application to alternating-current circuits, components, instruments, transformers, alternators, ac motors, and control equipment. Uses for […]
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Direct current fundamentals
Introduction to Alternating Current : Introduction and Angular relationships .
Introduction to Alternating Current INTRODUCTION Much of the electrical energy used worldwide is produced by alternating-current (ac) generators. Such widespread use of alternating current means that students in electrical trades must understand the principles of electricity and magnetism and their application to alternating-current circuits, components, instruments, transformers, alternators, ac motors, and control equipment. Uses for […]
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Solving dc networks : Norton’s theorem and summary of solving dc networks .
24–4 NORTON’S THEOREM Norton’s theorem, developed by American scientist E. L. Norton, is used to reduce a circuit network into a simple current source and a single parallel resistor. This is the opposite of Thevenin’s theorem, which reduces a circuit network into a simple voltage source and a single series resistor; see Figure 24–26. Norton’s […]
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Solving dc networks : Norton’s theorem and summary of solving dc networks .
24–4 NORTON’S THEOREM Norton’s theorem, developed by American scientist E. L. Norton, is used to reduce a circuit network into a simple current source and a single parallel resistor. This is the opposite of Thevenin’s theorem, which reduces a circuit network into a simple voltage source and a single series resistor; see Figure 24–26. Norton’s […]
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Solid-state control of dc motors : the shunt field power supply, armature control, current limit, speed control and summary of solid-state control of dc motors.
Solid-State Control of DC Motors 23–1 THE SHUNT FIELD POWER SUPPLY The shunt field power supply converts alternating current into direct current with a rectifier, as shown in Figure 23–2. The coil of a field loss relay (FLR) is connected in series with the shunt field. The field loss relay contains a current coil, not […]
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Solid-state control of dc motors : the shunt field power supply, armature control, current limit, speed control and summary of solid-state control of dc motors.
Solid-State Control of DC Motors 23–1 THE SHUNT FIELD POWER SUPPLY The shunt field power supply converts alternating current into direct current with a rectifier, as shown in Figure 23–2. The coil of a field loss relay (FLR) is connected in series with the shunt field. The field loss relay contains a current coil, not […]
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Solving dc networks : the loop current method , the superposition theorem and the venin’s theorem.
Solving DC Networks 24–1 THE LOOP CURRENT METHOD This method applies to circuits with a series of interconnected branches forming loops. Such circuits are also known as mesh circuits. The circuit in Figure 24–1 is an example of this. The solution of such circuits requires the following procedure: 1. Identify all the loops in the […]
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Solving dc networks : the loop current method , the superposition theorem and the venin’s theorem.
Solving DC Networks 24–1 THE LOOP CURRENT METHOD This method applies to circuits with a series of interconnected branches forming loops. Such circuits are also known as mesh circuits. The circuit in Figure 24–1 is an example of this. The solution of such circuits requires the following procedure: 1. Identify all the loops in the […]
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starters and speed controllers : definite time controller, electronic controllers and summary of starters and speed controllers.
22–10 DEFINITE TIME CONTROLLER This controller reduces starting resistance at a predetermined rate as the motor accelerates toward the desired speed. The contactors that close to accomplish this are controlled by either a small, motor-driven timer or by one of several types of magnetic timing devices. The schematic diagram, Figure 22–28, shows a definite time […]
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starters and speed controllers : definite time controller, electronic controllers and summary of starters and speed controllers.
22–10 DEFINITE TIME CONTROLLER This controller reduces starting resistance at a predetermined rate as the motor accelerates toward the desired speed. The contactors that close to accomplish this are controlled by either a small, motor-driven timer or by one of several types of magnetic timing devices. The schematic diagram, Figure 22–28, shows a definite time […]
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