I902. No. II. ON A NEW ELECTRIC CURRENT BREAKER. 



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Before being broken, the principal current of m ampères and n volts 

 is assumed mainly to pass through a shunt, a b d e, o( no practical 

 resistance, parallel to the coil C. 



At the moment of breaking, ^the chief conductor is opened lirst at 

 b, so that almost the whole current is forced to act only in the coil, if 

 that is assumed to have little resistance relatively to the whole system 

 of conducting wires. The iron core will then be violently drawn in, 

 thereby inducing a very great counter-tension, this again creating a 

 contrary current, which, by choosing the dimensions of the inducting 

 system, we can make equal in intensity, but reverse, to the original 

 current of »i amperes. The total intensity of the current at this moment 

 is then o, and the conducting circuit may be quickly opened, without 

 the emission of sparks. 



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Fig. I. 



The construction of a lever by means of which the breaking is 

 accomplished by a single act, presents no difficulty. 



Fig. I is a diagram of an apparatus such as this. In the position 

 in which the lever, b d, is represented, the main current passes from a 

 through the contact b and the axis d to c. When the lever is raised, 

 the whole current is forced to pass through the coil C, and simultane- 

 ously a hook, f, is mechanically disengaged, setting the iron core free. 

 This will immediately be attracted, and will induct a strong contrary 

 current in C, so that the intensity of the current may be o when the 

 core arrives at i. Here it compresses a strong spiral spring, k, whereby 

 the contact, h, is quickly opened without the production of sparks. The 

 iron core is afterwards drawn back to its original position by a weaker 

 spiral spring, g. 



