Small generators sometimes lose their residual magnetism and it is then impossible to start them generating.
The incepting energy influence is found in the residual magnetism.
The residual magnetism is small when the core is made of small wires or thin plates, but is larger when the iron core is solid.
What may be said of the field due to this residual magnetism?
At the start the residual magnetism of the magnet cores gives a weak field.
A machine in which the initial excitation of the field is due to the residual magnetism retained by the cores.
This pressure is due to the residual magnetism in the field cores, as the field coils are not yet connected.
(B) If there is any residual magnetism, strike the core with a hammer and test again.
The residual magnetism should hold them against the cores until removed.
The magnetism remaining in the iron after the current stops is called the residual magnetism.