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Why flux control method is independent of the load but armature control method depends on load in shunt motor?
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Name the three basic methods that are used to vary the speed of a DC motor?
speed of a dc motor can be varied by mainly two methods:- 1)field control method 2)armature control method further , field control method can be divided in 3 parts:- 1)field rhestat control method---speed variation is acomplished by means of a variable resistance inserted in series with shunt field 2)reluctance control method---by changing the reluctance of magnetic circuit by choosing right material.. 3) field voltage control method-requires variable field voltage supply. and armature control method can be divided in 3 parts :- 1)armature resistance control---variable resisitance connected in series with armature 2)shunted armature control. 3)armature voltage control. ------------mrityunjay pandey (kiit university ,btech 2nd year)
Remedies for Armature reaction?
Since an armature is wound with coils of wire, a magnetic field is set up in the armature whenever a current flows in the coils. This field is at right angles to the generator field, and is called cross magnetization of the armature. The effect of the armature field is to distort the generator field and shift the neutral plane. The neutral plane is the position where the armature windings are moving parallel to the magnetic flux lines. This effect is known as armature reaction and is proportional to the current flowing in the armature coils. The brushes of a generator must be set in the neutral plane; that is, they must contact segments of the commutator that are connected to armature coils having no induced emf. If the brushes were contacting commutator segments outside the neutral plane, they would short-circuit "live" coils and cause arcing and loss of power. Armature reaction causes the neutral plane to shift in the direction of rotation, and if the brushes are in the neutral plane at no load, that is, when no armature current is flowing, they will not be in the neutral plane when armature current is flowing. For this reason it is desirable to incorporate a corrective system into the generator design. These are two principal methods by which the effect of armature reaction is overcome. The first method is to shift the position of the brushes so that they are in the neutral plane when the generator is producing its normal load current. in the other method, special field poles, called interpoles, are installed in the generator to counteract the effect of armature reaction. The brush-setting method is satisfactory in installations in which the generator operates under a fairly constant load. If the load varies to a marked degree, the neutral plane will shift proportionately, and the brushes will not be in the correct position at all times. The brush-setting method is the most common means of correcting for armature reaction in small generators (those producing approximately 1000 W or less). Larger generators require the use of interpoles.
The loci method depends on what you can?
see
Why do you need to control the speed of a DC motor?
The speed of DC motors need to be controlled because that is what the application needs. In some cases, it is to protect the motor or the attached equipment. In toys and robots, you'd want different speeds. Electric cars such as golf carts would need to control the speed of a DC motor so you can easily drive it like driving a car with a gasoline engine. Tape recorder motors contain a flywheel and a governor to regulate their speed so the tape will move at an even and standard rate. If the motor starts to get a little too fast, its contacts inside open up to briefly power down the motor and when it is slow enough, the contacts close again. So this helps to compensate for different amounts of battery charge and for different operating conditions. Record players have a simpler job of regulating their speed since most use alternating current and a simple induction motor. Since the voltage and frequency is constant, no governors are needed. Unless the bearings go bad, the motor will run at that fixed rate.
Indirect method of testing of dc machine?
Losses are measured separately in this method, and efficiency at any desired load is predetermined. The iron and friction losses can be determined by measuring the input to the machine at no-load. The machine is run as a motor at normal voltage and speed. The copper losses are calculated from measured values of the various resistances. This method is only applicable to level compounded and shunt motors. Figure 5.29shows the circuit diagram of Swinburne's test.Figure 5.29 Swinburne's TestLet Vt be the supply voltage, I0 be the input armature current at no-load(measured by ammeter A1) andIsh be the shunt field current(measured by ammeter A2) for Figure 5.29.Therefore, no-load armature current (Ia0) = I0 - Ish, no-load input = VtI0 W, power input to the armature = Vt (I0 - Ish) W and power input to shunt = VtIsh W.
In what two ways can the speed of a dc motor be varied?
speed of a dc motor can be varied by mainly two methods:- 1)field control method 2)armature control method further , field control method can be divided in 3 parts:- 1)field rhestat control method---speed variation is acomplished by means of a variable resistance inserted in series with shunt field 2)reluctance control method---by changing the reluctance of magnetic circuit by choosing right material.. 3) field voltage control method-requires variable field voltage supply. and armature control method can be divided in 3 parts :- 1)armature resistance control---variable resisitance connected in series with armature 2)shunted armature control. 3)armature voltage control. ------------mrityunjay pandey (kiit university ,btech 2nd year)
What is common methods control speed dc motor?
there are two methods i.e armature control method and field control method....
What are the disadvantages of armature speed control method for a dc motor?
In armature speed control, speed can be varied only below the rated speed. Also in it voltage drops will be high.
Why is a control needed in a scientific method?
Because In a scientific method there has to be a independent,controll,and dependent variable. A control group has to be in a scientific method cause ther is only one needed.
Name the three basic methods that are used to vary the speed of a DC motor?
speed of a dc motor can be varied by mainly two methods:- 1)field control method 2)armature control method further , field control method can be divided in 3 parts:- 1)field rhestat control method---speed variation is acomplished by means of a variable resistance inserted in series with shunt field 2)reluctance control method---by changing the reluctance of magnetic circuit by choosing right material.. 3) field voltage control method-requires variable field voltage supply. and armature control method can be divided in 3 parts :- 1)armature resistance control---variable resisitance connected in series with armature 2)shunted armature control. 3)armature voltage control. ------------mrityunjay pandey (kiit university ,btech 2nd year)
What do limitig factors control?
if the question refers to Independent, dependent and control variables, then the limiting factors are the control variables which are the items that will not be changed or modified during an experiment for more information, please refer to the 'scientific method"
Breathing depends on a partition of muscle and connective tissue that shares its name with what birth control method?
Diaphragm
What variable is affected by the independent cariable in the scientific method?
the independent variable
Do the independent and dependent variables go under experiment on the scientific method?
Independent and dependent does go under experiment on the scientific method.
Does a correlation tell us anything about cause?
No a correlation method does not prove any kind of cause the only method that will prove Cause and Effect would be a Experiment Lab(hypothesis, Control group, Independent Variable ext...)
In a scientific method the factor that may change in response to the manipulated variable is called the responding or?
It is called the dependent variable because it depends on what the independent variable is doing.
What is control in the scientific method?
The control of the scientific method is the results compared to this part of the experiment.
