if any of the connection are reversed ... then armature flux will oppose field flux ... it will net result in reduction of speed ... n may be reversal ... but if both the connections are reverse ... then it will keep rotating in the same direction ...
series field in series with the armature shunt in parallel with the voltage supply the shut field increases the strength of the magnetic field with heavy loads to reverse the motors direction the fields remain the same you swap the armature leads
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!
Because the armature (or rotor) has no external connection. The currents that produce torque from the rotor are induced by the magnetic field in the machine, so there is no commutator, no brushes and no armature reaction.
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
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
Reverse the armature connections or the field connections, but not both.
DC shunt motor can be reversed by changing the polarity of either the armature coil or the field coil.
series field in series with the armature shunt in parallel with the voltage supply the shut field increases the strength of the magnetic field with heavy loads to reverse the motors direction the fields remain the same you swap the armature leads
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!
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!
Because the armature (or rotor) has no external connection. The currents that produce torque from the rotor are induced by the magnetic field in the machine, so there is no commutator, no brushes and no armature reaction.
Change the polarity of either the field coils or the armature, not both and you will reverse rotation.
armature reaction means when load is added to the armature then current is passed through armature conductors then in armature creates flux. It is demagnetize and cross magnetize the main field flux. in other ward it is effect of armature field on main field.
Difference between field controlled and armature controlled is that field control is open loop and armature current is closed loop.
In case of 1phase the reverse torque is obtained by reversing the current either in armature or field
a general purpose D-C motor can be reversed by changing the polarity of either the armature or the field but not both
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