The Diseases Of Electrical Machinery

4+ THE DIS EAS ES OF will happen in this case, one will find that the motor may start without load, but not with load. The further the starting lever is turned the more the shunt current is diminished, until finally no current at all flows through the magnet. The motor will then either run L. N. A. Fig. 26. <www away, sparking furiously, or else stop dead and burn out. A further false method of connection is shown in Fig. 26. Here the terminals A and L have been inter- changed. The result is that the shunt current is much weakened at starting, where- fore in most cases the motor will not start. If it does run, however, it will then run better from con- tact to contact, until finally the end contact is reached, when it is then correctly connected. In this case the fault occurs which is represented in Fig. 21. Various other Faults.—We have now said enough on this subject, and turn to the last division of our catalogue of the faults of continuous-current machines. We will here consider different causes of trouble which do not fali under any of the above head- ings. A fault which often occurs is the loss of the remanent magnetism of a machine. This may be caused in two ways; first, owing to the machine not having been used for a long time, and secondly, through false magnetisation of the poles.