Saved Bookmarks
| 1. |
What Is Back E.m.f Or Counter E.m.f? |
|
Answer» When the armature of a d.c. motor rotates under the influence of the driving torque, the armature CONDUCTORS move through the MAGNETIC field and hence e.m.f. is induced in them as in a generator. The induced e.m.f. acts in opposite direction to the applied voltage V (Lenz’s law) and in known as BACK or counter e.m.f Eb. It is always less than the applied voltage V, although this DIFFERENCE is small when the motor is running under normal conditions. When the armature of a d.c. motor rotates under the influence of the driving torque, the armature conductors move through the magnetic field and hence e.m.f. is induced in them as in a generator. The induced e.m.f. acts in opposite direction to the applied voltage V (Lenz’s law) and in known as back or counter e.m.f Eb. It is always less than the applied voltage V, although this difference is small when the motor is running under normal conditions. |
|