0
Why direction of rotation is not reversed when both field and armature terminals are reversed?
Wiki User
∙ 11y ago
The direction of the force that drives the machine is determined by the relative directions of the field and the armature current. By reversing the direction of both field and the armature current, the direction of the resulting force stays the same; you have to reverse the direction of one or the other; not both! Prove it for yourself, by applying Fleming's Left-Hand Rule (for conventional current flow); reverse the direction of both your first finger (field) and your second finger (armature current), and you thumb (direction of motion) will end up pointing in the same direction!
Wiki User
∙ 11y ago
Add your answer:
Earn +20 pts
What is a rocker arm in a DC motor and what will happen if the rocker arm connections are changed?
A rocker arm holds a carbon brush. In other words it is a carbon brush holder. Changing over the rocker arm connections is the same as changing over the armature connections and will make a DC motor turn in the reverse direction assuming that the magnetic orientation of the motor's field stays the same.More detailDC motor having a field windingIf the stator's field is created by a field winding and that winding's connections are changed over at the same time as the armature's connections are changed over, then the DC motor's direction of rotation will be the same as before.If the stator's field is created by a field winding and that winding's connections are not changed over at the same time as the the armature's connections are changed over, then the DC motor will turn in the reverse direction.DC Motor having a field created by a permanent magnetIf the stator's magnetic field is created by a permanent magnet and the orientation of that magnet is reversed at the same time that the armature connections are changed over, then the DC motor's direction of rotation will be the same as before.If the stator's magnetic field is created by a permanent magnet and the orientation of that magnet is not reversed at the same time as the armature connections are changed over, then the DC motor will turn in the reverse direction.
What happen when you reverse the direction of rotation in a separately excited dc generator?
When reverse the direction of a seperately excited DC generator,only polarities has been reversed,i.e., (+) becomes (-) and (-) become (+).
What is the principle of operation of universal motor?
Similar to DC permanent magnet motor (which I'm assuming you understand); except the stator is not a permanent magnet but an electromagnet. There are 2 separate coils on the stator, which are connected in series with the brushes and armature: supply ----- stator segment --- brush - armature - brush --- stator segment ----- return Since the stator coil segments are wired in series with the armature, reversing the supply will *not* change the direction of rotation; as both magnetic fields will reverse together. (But a reversing switch affecting only the armature *will* reverse the rotation.) And since the motor will always turn in the same direction independent of the supply polarity, this means it will work equally well from DC or AC; and the supply frequency will not affect the rotation speed.
What is the function of field winding in DC generator?
The motor needs the current and magnetic flux to create motion The magnetic field is created by field winding where as armature carries the current resulting into the rotation of armature
What determines the magnitude and polarity of the counter-emf in a dc motor?
the magnitude is decided by the amount of flux, number of conductors, speed of the motor and the type of the winding used. the polarity is decided by the direction of rotation of the motor and the direction of armature current flowing in the motor.
How could the direction of rotation of the universal motor be reversed?
Change the polarity of either the field coils or the armature, not both and you will reverse rotation.
How can the direction of rotation of a DC shunt motor be reversed?
DC shunt motor can be reversed by changing the polarity of either the armature coil or the field coil.
Why direction of rotation is not reversed when both field and armature terminal are reversed?
The direction of the force that drives the machine is determined by the relative directions of the field and the armature current. By reversing the direction of both field and the armature current, the direction of the resulting force stays the same; you have to reverse the direction of one or the other; not both! Prove it for yourself, by applying Fleming's Left-Hand Rule (for conventional current flow); reverse the direction of both your first finger (field) and your second finger (armature current), and you thumb (direction of motion) will end up pointing in the same direction!
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.
In what two ways can the rotation of a shunt connected dc motor be reversed?
DC shunt motor can be reversed by changing the polarity of either the armature coil or the field coil.
How could you reverse the rotation of the motor?
The motor will spin the direction that the positive lead is on. So if the shaft is pointing towards you, you will need to put the positive lead on the left side to make it turn counter clockwise.
How could the electromagnet and the regular magnet generate electricity?
Before going to the answer first I'd like to tell that Magnet alone cannot produce electricity. We need an armature. Armature contains poles. Consider that armature is placed in between the magnetic poles(North and south poles) and let it face any direction. Due the magnetic field the armature tend to move towards anyone pole in order to make its direction coherent with the magnetic field direction. It results that armature is aligned with the magnetic field direction(lets say facing North). Then the other pole(South pole) tend to attract the armature to align in its direction say(facing South). This results in rotation of the armature in the magnetic field. due to this rotation of armature cuts the flux there emf is produced. This emf cause the current in that construction. This is how the electricity is produced using any magnet called Electromagnet or Permanent magnet.
What allows rotation in One Direction?
A: The earth spin cause a Coriolis effect In south America the spin is reversed.
What happens if the direction of current at the terminals of a series motor is reversed?
No changes will occur by wiring a 110 volt motor in reverse polarity, rotation will always be the same. Some single phase motors are designed to be reversed ,but that is a function of the relationship of start windings and capacitors and requires some wiring changes in a motor junction box or an end terminal housing, not by just changing the incoming power.
If the direction of rotation of the Earth were reversed and the direction of revolution remained the same would the sidereal day be longer than the solar day?
Yes, I believe you have that correct.
What is a rocker arm in a DC motor and what will happen if the rocker arm connections are changed?
A rocker arm holds a carbon brush. In other words it is a carbon brush holder. Changing over the rocker arm connections is the same as changing over the armature connections and will make a DC motor turn in the reverse direction assuming that the magnetic orientation of the motor's field stays the same.More detailDC motor having a field windingIf the stator's field is created by a field winding and that winding's connections are changed over at the same time as the armature's connections are changed over, then the DC motor's direction of rotation will be the same as before.If the stator's field is created by a field winding and that winding's connections are not changed over at the same time as the the armature's connections are changed over, then the DC motor will turn in the reverse direction.DC Motor having a field created by a permanent magnetIf the stator's magnetic field is created by a permanent magnet and the orientation of that magnet is reversed at the same time that the armature connections are changed over, then the DC motor's direction of rotation will be the same as before.If the stator's magnetic field is created by a permanent magnet and the orientation of that magnet is not reversed at the same time as the armature connections are changed over, then the DC motor will turn in the reverse direction.
Why does the rotation of the motor reversed when change the polarity across the main winding coil?
When changing the auxilary face winding connection the current flow in the winding is changed so that the rotating emf direction is changed . Thats why the motor rotates in opposite direction.
