Earth Is the Lords
5th Edition
ISBN: 9781121660069
Author: Caldwell, Taylor
Publisher: MCG/CREATE
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Question
Chapter 3, Problem 3.10P
(a).
To determine
The speed of the magnetic field rotation for the given set of poles at
(b).
To determine
The difference in the core losses of the motor running at
(c).
To determine
The reasons why there was separate 60Hz power system for lightning was adopted by early engineers.
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Write a technical manual of that will inform others of the efficiency and inefficiency of all types of motor and generator (ac and dc). Explore how any apparent inefficiencies could be improved. Show examples of these machines and using suitable examples, point out the areas of inefficiency (if applicable) and where and how things can be improved. Then provide the solution to the following as an example in your report. A 2-pole, single-phase alternator driven at 3000rpm require a mechanical input to its rotor of 30kW when it is delivering its full-load output of 30kW. Under this condition the fixed and variable losses are1100W and 2.8kW respectively, and the rotor field winding is supplied from a 110V dc source. Given that the full-load efficiency is 87%, determine. i) the frequency generated, ii) the input driving torque on full-load and iii) the rotor field current
Write a technical manual/ documentation, that will inform others of the efficiency and inefficiency of all types of motor and generator (ac and dc). Explore how any apparent inefficiencies could be improved. Show examples of these machines and using suitable examples, point out the areas of inefficiency (if applicable) and where and how things can be improved.
Then provide the solution to the following as an example in your report.
A 2-pole, single-phase alternator driven at 3000rpm require a mechanical input to its rotor of 30kW when it is delivering its full-load output of 30kW. Under this condition the fixed and variable losses are1100W and 2.8kW respectively, and the rotor field winding is supplied from a 110V dc source. Given that the full-load efficiency is 87%, determine.
the frequency generated,
the input driving torque on full-load and
the rotor field current
6. A separately-excited dc generator has no load output voltage of 120 V. its equivalent armature resistance is 0.95 Ω. If a load rated 2000 W at 115 V is connected across its terminals, what power is delivered to the load?
Chapter 3 Solutions
Earth Is the Lords
Ch. 3 - What is the principal difference between a...Ch. 3 - Prob. 3.2QCh. 3 - Prob. 3.3QCh. 3 - What is the equation for the induced torque in an...Ch. 3 - The simple loop rotating in a uniform magnetic...Ch. 3 - Prob. 3.2PCh. 3 - The first ac power system in the United States ran...Ch. 3 - A three-phase, Y-connected, four-pole winding is...Ch. 3 - A three-phase, -connected, six-pole winding is...Ch. 3 - A three-phase, Y-connected, 60 Hz, two-pole...
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- A d.c. shunt machine has armature and field resistances of 0.025 Ω and 80 Ω respectively. When connected to constant 400-V bus-bars and driven as a generator at 450 r.p.m., it delivers 120 kW. Calculate its speed when running as a motor and absorbing 120 kW from the same bus-barsarrow_forwardA 4 pole armature of a DC machine has 175 conductors and a flux per pole of 0.1 wb. Find the EMF generated when running at 600 rpm, when the armature is Lap wound.arrow_forwardThe armature and field resistances of a series machine are 0.2 ohm and 0.3 ohms respectively. While running as a generator, the generated emf is 250V at 1200rpm. If the machine is run as motor, it takes 4A at220V. At a certain load, the motor takes 30A at 220V. However, on load, the armature reaction weakens the field by 4%. Find the motor speed at this load.arrow_forward
- What are the methods of excitation of the field windings of the DC machines? Draw the corresponding diagrams.arrow_forwardA DC Machine running at 1200 rpm has its eddy and hysteresis losses at 125 and 250 W respectively. At constant flux, if the total core losses are reduced by 50%, find the speed at this condition.arrow_forward. When a self-excited compound DC generator supplies load, the terminal voltage is not the same as the generated emE Why? a) voltage drop across the armature resistance will reduce the voltage available at the load terminals b) where there is a series field, voltage drop across the series field resistance will reduce the voltage available at the load terminals c) both "a" and "b" d) neither "a" nor "b"arrow_forward
- Write an article describing the DC Generator. Provide applications of DC generator. Provide the importance of a DC generatorarrow_forwardA 220 V , 60 Hz , supply is connected to 200 – turn armature winding of reluctance 1.7x105 At / Wb . Find the magnetizing reactance , the rms values of the ( magneto – motive force , exciting and armature currents , magnetic flux ) , and the inductance Draw the phasor diagram of the circuit .arrow_forwardDC MACHINES EDDY CURRENT LOSS AND HYSTERESIS LOSS In a dc machine, running at 500 rpm the hysteresis and eddy current losses are 350watts and 100 watts respectively. Find the speed at which the total core loss arereduced by 30 percent.arrow_forward
- The current generated by the waterwheel generator changes direction as the wheel rotates, that is, it is an alternating current. Could you design a simple generator like this that would induce a current that continuously flowed in one direction (a DC current)? If not, explain why not. If so, describe and sketch your model solution below.arrow_forwardThe armature of a dc motor has 648 conductors, 65 % of which are directly under the pole where the flux density is 48,000 lines per in2. If the core diameter is 7 inches and its length is 4 inches and the current in each conductor is 20 A. What is the torque exerted in the armature in N-m?arrow_forward111/ The armature reaction of the DC generator reduces the generated EMF. Select one: True Falsearrow_forward
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