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A motor will turn when only the armature is excited, if there is enough residual magnetism in the field.
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∙ 14y ago
Wiki User
∙ 9y agoA permanent-magnet dc motor would turn when a voltage is applied to the armature via the commutator.
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Would a DC motor turn if only the armature were supplied DC voltage?
if there are magnets on the stator and the commutator is phased properly this is known as a permanent magnet dc motor the starting torque is dependent on armature current and the strength of the magnet the speed is directly proportional to the armature voltage a shunt motor needs the field energized for starting. more field more starting torque
How does a wiper motor work?
A wiper motor is a DC motor with two permanent magnets that serves as a field for the motor, arranged around the armature where the power is connected to the commentator of the armature with two brushes, the armature is a set of electro magnetic coils that is each connected to its own two segments in the commentator so that the power is connected to only one coil at a time to generate a magnetic field in the armature, this field will appose the field of the permanent magnet field, where the one field will push the other away and make the motor to turn.
What is the purpose of the fields of a dc shunt motor?
DC Shunt motor: dc shunt motor is a motor with dc supply given to the inductor connected in parallel with the armature of a motor. The inductor connected in parallel with the armature of a motor called field winding of a motor.In dc shunt motor: When current flows through a conductor ( here it is armature in case of dc shunt motor ), magnetic field is produced which is circular and when this conductor is placed perpendicular in the magnetic field ( which is produced by the current or say dc supply that given to the inductor or say field winding of the dc shunt motor ), the main magnetic lines get bent due to the interaction of the two fields. These lines of force experience tension and try to become straight. So, a force is produced on the conductor ( armature ), due to which the conductor ( armature ) will rotates. The direction of force can be found by Fleming's right hand rule.Main Answer: Thus, it should be understood that field winding in dc shunt motor stands to get interaction of the two field in such a way that force is produced on the armature so that the armature get to rotate.Some Facts: Actually the current in armature is due to the mutual induction by field winding to the armature. That means only field winding get dc supply through which current and so magnetic field is produced in armature that try to oppose due which it is produced, that means it oppose the main magnetic field of field winding.
Why a DC series motor should never be stared without load?
since torque is proportional to flux and armature current . Flux for dc shunt is constant . torque is proportional to armature current only. And initially armature current is very low hence it cannot be started at load .
Why the armature rheostat of dc is motor kept at maximum resistance position?
It isn't. It is only kept at maximum resistance when the motor is not running. That is done to limit the starting current.
When a shunt generator fails to build up the voltage then how to rectify the fault?
It fails to build up because self excited DC motor's armature have only one direction of rotation. So that if the poles of the armature are reversed, then this causes the reduction in the residual magnetism and eventually, it will stop.
The back emf indcuced in the armature is AC or DC?
only in dc motor...
Would a DC motor turn if only the armature were supplied DC voltage?
if there are magnets on the stator and the commutator is phased properly this is known as a permanent magnet dc motor the starting torque is dependent on armature current and the strength of the magnet the speed is directly proportional to the armature voltage a shunt motor needs the field energized for starting. more field more starting torque
How does a wiper motor work?
A wiper motor is a DC motor with two permanent magnets that serves as a field for the motor, arranged around the armature where the power is connected to the commentator of the armature with two brushes, the armature is a set of electro magnetic coils that is each connected to its own two segments in the commentator so that the power is connected to only one coil at a time to generate a magnetic field in the armature, this field will appose the field of the permanent magnet field, where the one field will push the other away and make the motor to turn.
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.
Is there any real reason not to use a jigsaw to cut sheetrock?
The only real reasons not to would be the dust created. Breathing it and what would be sucked into the motor of the jigsaw. It will tend to pack around the armature of the motor and cause it to lock up after a while.
Want to know about two point starter?
In DC series motor, field and armature are in series. so we use only two points. They are line and armature. therefore we use two point starter.
Will a singl phase induction motor start if only the running or the starting winding is excited?
No.
What is the purpose of the fields of a dc shunt motor?
DC Shunt motor: dc shunt motor is a motor with dc supply given to the inductor connected in parallel with the armature of a motor. The inductor connected in parallel with the armature of a motor called field winding of a motor.In dc shunt motor: When current flows through a conductor ( here it is armature in case of dc shunt motor ), magnetic field is produced which is circular and when this conductor is placed perpendicular in the magnetic field ( which is produced by the current or say dc supply that given to the inductor or say field winding of the dc shunt motor ), the main magnetic lines get bent due to the interaction of the two fields. These lines of force experience tension and try to become straight. So, a force is produced on the conductor ( armature ), due to which the conductor ( armature ) will rotates. The direction of force can be found by Fleming's right hand rule.Main Answer: Thus, it should be understood that field winding in dc shunt motor stands to get interaction of the two field in such a way that force is produced on the armature so that the armature get to rotate.Some Facts: Actually the current in armature is due to the mutual induction by field winding to the armature. That means only field winding get dc supply through which current and so magnetic field is produced in armature that try to oppose due which it is produced, that means it oppose the main magnetic field of field winding.
Explain the necessity for the use of a starter with a dc motor?
In its simplest form, the starter of a dc motor is a variable resistance in series with the armature circuit of dc motor to reduce the high starting current so that the armature winding does not get overheated and burnt while the motor isgetting started. As the rotating armature of dc motor picks up speed, the starter resistance is gradually reduced so that the motor is able to attain its full speed when the starter is not expected to offer any additional resistance in series with the armature winding of the dc motor. At full speed the motor starts running normally, of course, without the help of starter. In other words, the starter offers resistance to armature current during starting of dc motor only. Under normal working condition of dc motor , the starter is electrically out of armature circuit of the motor. The starter protects the armature of dc motor from getting damaged. The electromotive force (emf) induced in the armature winding during starting builds up from zero value to max value to restrict the armature current within the permissible value at full speed. As the speed of armature/motor build up, armature induced emf also starts building thus reducing the role resistance offered by the starter, hence requiring it to gradually reduce as the motor picks up full speed.
Why a DC series motor should never be stared without load?
since torque is proportional to flux and armature current . Flux for dc shunt is constant . torque is proportional to armature current only. And initially armature current is very low hence it cannot be started at load .
Why the armature rheostat of dc is motor kept at maximum resistance position?
It isn't. It is only kept at maximum resistance when the motor is not running. That is done to limit the starting current.
