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What are the causes of failure of d.c shunt generator to excite?
no residual magnetism in the stator. this can happen with an overload which will occasionally even reverse the output polarity
What takes place when the energizing of a chime circuit as the push button is pushed?
Electrical current in solenoid creates a magnetic field.Magnetic field in solenoid pulls in armature.Armature causes striking mechanism to produce first chime of bell.Interruption of electrical current in solenoid causes magnetic field to collapse.Spring pulls armature out of solenoid.Armature causes striking mechanism to produce second chime of bell.Electronic doorbell chimes work differently, offering more options.
What is armature reaction in dc motor?
Armature reaction is effect of armature flux on main field flux. Basically there are two windings in a dc motor - Armature winding (on stator) and field winding (on rotor). When we excite the field winding, it produces a flux which links with the armature. This causes an emf and hence a current in the armature. This current in armature produces another flux which lags the main flux. This is referred to as armature reaction. It has two effects on the machine: 1. Demagnetising effect: It reduces the strength of the main flux. 2. Crossmagnetising effect: Its effect is that it bends/distortes the the main flux line along the conductor
Armature reaction in a DC generator?
ARMATURE REACTION in DC MachineAll current-carrying conductors produce magnetic fields. The magnetic field produced by current in the armature of a dc generator affects the flux pattern and distorts the main field. This distortion causes a shift in the neutral plane, which affects commutation. This change in the neutral plane and the reaction of the magnetic field is called armature reaction.
Operation of DC generator?
1) PRINCIPLE:Whenever a conductor cuts magnetic flux, dynamically induced emf is produced in it. ( Faraday's Laws of Electromagnetic Induction ). This emf causes a current to flow if the conductor circuit is closed.2 ) OPERATION:Field winding produces magnetic field in D.C. generator. Armature is coupled to the prime mover. Prime mover produces torque so the armature rotates. The armature cuts the magnetic field so the emf is induced in the armature. When load is connected to the armature, electric current flows from the armature conductors, through load and back to the armature conductors. Now, as current flows through the armature and it is in the magnetic field, torque is produced due to it. (This torque is called back torque). If the load on the generator is increased, the back torque increases so the torque of the prime mover also increases and the input power to the prime mover increases. In this way, the generator converts mechanical energy into electrical energy.It should be observed that the emf induced in D.C. generator, is A.C. ( so the emf induced in the armature is alternating in nature. ). Then with the help of commutator, it is converted into D.C. Rings and brushes are used to take the emf outside.
What are the causes of failure of d.c shunt generator to excite?
no residual magnetism in the stator. this can happen with an overload which will occasionally even reverse the output polarity
What causes erratic idle when shifting to reverse?
might be bad motor mount / or electrical short
What is an example of reverse polarity?
Reverse polarity means connecting a power source, or polarised componenet, with the positive and negative poles the wrong way round. If the positive and negative supply is connected the wrong way round in electronic devices, it usually causes damage, because semiconductors are sensitive to polarity. Sometimes protection is provided, so that reverse polarity stops the device from working without causing damage. Connecting a diode (or rectifier) in reverse, will block the flow of current, without causing damage and is useful in protecting circuits from reverse polarity. In some consumer electronics (especially CB Radios) the power input has a recitifier across the 12v supply. If it is wired correctly, the rectifier is in reverse polarity, does not conduct and allows the radio to work. If you reverse the polarity of the power supply, the rectifier is now in full conduction, across the supply, causing a dead short. This shunts any power away from the radio and blows the fuse in the line, thus protecting it.
What will happen if AC motor is fed by mistake to a DC motor?
It depends on whether the field winding of the dc motor is connected in series or in shunt with the armature winding.If it is connected in series,the motor will rotate since the torque,which varies as the product of the armature and field current is always positive.Thus,a positive average torque causes the motor to rotate,however the pulsating nature may cause the commutator segments and brushes to wear out. Thus only small sized dc motors may be used with ac supply.
What causes no reverse gear In an automatic transmission?
Low fluid, shifter malfunction, electrical malfunction, internal mechanical malfunction.
Switching of the poles?
Switching of the poles refers to a reversal of the Earth's magnetic field, where the North and South magnetic poles switch places. This phenomenon has happened many times in the Earth's history and is believed to be a natural process. Scientists are studying the potential impact of a future pole reversal on technology and the environment.
When a current flows through an electric bell what will happen to the armature?
When a current flows through an electric bell, it creates a magnetic field that causes the armature, attached to a spring, to be attracted towards the electromagnet. This movement causes the armature to strike the bell, producing a ringing sound.
What is the function of a stator in an alternator?
The stator is the stationary part. It consists of electromagnets which are energized when the battery sends current to the fields. The alternator belt turns the pulley. The pulley is directly attached the the rotary part of the alternator, called the armature. It is the same principle as an ordinary AC or DC motor. The armature turns inside the stator, which causes electrical current.
What causes a starter to draw too much power from the battery?
bad armature bushings
What causes the polarity of a water molecule?
the unequal sharing of electrons
What takes place when the energizing of a chime circuit as the push button is pushed?
Electrical current in solenoid creates a magnetic field.Magnetic field in solenoid pulls in armature.Armature causes striking mechanism to produce first chime of bell.Interruption of electrical current in solenoid causes magnetic field to collapse.Spring pulls armature out of solenoid.Armature causes striking mechanism to produce second chime of bell.Electronic doorbell chimes work differently, offering more options.
What is armature reaction in dc motor?
Armature reaction is effect of armature flux on main field flux. Basically there are two windings in a dc motor - Armature winding (on stator) and field winding (on rotor). When we excite the field winding, it produces a flux which links with the armature. This causes an emf and hence a current in the armature. This current in armature produces another flux which lags the main flux. This is referred to as armature reaction. It has two effects on the machine: 1. Demagnetising effect: It reduces the strength of the main flux. 2. Crossmagnetising effect: Its effect is that it bends/distortes the the main flux line along the conductor
