GB229564A - - Google Patents

Abstract

229,564. Paul, M. March 13, 1924. [Convention date]. Automatic circuit-breakers.-An element, Fig. 1, of some ferro-magnetic substance such as iron, nickel, or an alloy of 92 per cent nickel and 8 per cent copper, is inserted as at B, Fig. 2a, in the magnetic circuit of a permanent magnet A and its armature D, the element being insulated from the magnet by mica sheets C1, C2. The element is connected in the circuit to be protected and upon overload, the heat generated in the element lowers its magnetic permeability and reduces the force of attraction upon the armature which is forced upwards by a spring G causing the circuit to be broken at contacts E1, F1 and E2, F2. A rod J fixed to the armature serves as an indicator and also as a means for resetting the apparatus. Another element, Fig. 1, may be inserted in the armature if desired, and according to a further modification. two elements in series are inserted in the poles of the magnet A. Fig. 4<a> shows a modification which prevents closure of the circuit by hand if the overload persists. To close the circuit, a rod M connected to a conducting disc N is depressed. The disc N carries the armature D with it and closes the contacts E1, F1, E2, F2. The circuit however is not closed till the rod M is released amd the disc N is allowed to move upwards again to connect contacts Q1, Q2 which are in series with the other contacts.