Patent GB-190927604-A (GB)
Title: An Improved System for the Production and Supply of Electricity at Given Tensions by Means of Variable-speed Dynamos for Railway Carriages.
Inventor: CRAWFORD ARCHIBALD ALLAN
IPC: H02J7/18
Filed: 1909-11-26
Granted: 1910-11-24
Abstract: 27,604. Crawford, A. A, Nov. 26. Switches.-In connexion with a train-lighting system dependent upon a variable-speed dynamo and a battery, various switches are used as follows :- Electrically-tripped switches.-(i). A batterydischarge limiter consists of a spring controlled switch O which is closed by hand and retained by engagement with an armature. When the magnet controlling the armature is energized by a relay P, the switch O is tripped open. (ii). An overload cut-out Y consists of a bridge Y<12> carried by an armature Y<4> and normally engaging contacts Y<13>, Y<14>. When the coil of the cut-out is energized by an overload relay, the armature Y<4> is attracted and latched open by an auxiliary armature Y<1>4, Y<1>6, a signal lamp A<1> being illuminated by the closing of contacts Y<22>, Y<23>. The latch Y<1>4 also closes contacts Y<1>19 in the circuit of a release magnet Y11, which when energized by a relay trips the armature Y<4> and allows the cut-out Y to close again. Electro-magnetic switches.-(i). A switch E is operated by a shunt winding E<4>, and a series winding E<5> is thrown into circuit when the switch closes. In the open position of the switch, additional circuits are closed at the contacts E<15>, E<16>, and the contacts Y<20>, Y<21>. (ii). A relay XG<1> is provided with two armatures X<4>, G<4>, the former acting to short-circuit a resistance X<17> when the dynamo output exceeds a given value, while the latter, G<4> operates upon the occurrence of an overload to close the opening coil of the cut-out Y described above. (iii). A voltage relay W consists of a solenoid W<2>, the core W<1> of which is carried by a pivoted arm provided with contacts W<12>, W12<1> mounted upon a piece of soft iron W<26>. The corresponding fixed contacts W<13>, W13<1> are wound with coils W<30> enclosed by an iron armouring. When the fixed and moving contacts engage, the coils W<30> are energized, and the magnetic action produced operates to hold the contacts in firm engagement besides providing a blow-out action when they again separate. (iv). A resistance regulator consists of two horseshoe magnets T<10>, T<11>, T<14>, T<15> which operate by means of an armature T<4> and pawls T<25>, T25<1> to drive a rack carrying a contact T<12> in either direction over resistance contacts T<16>. The armature is normally held in a central position by springs T<7>. Electro-magnetic interrupters.-(i). Two engaging contacts K<12>, K<13> are carried by horizontal blade springs, and are in series with an operating magnet the armature of which is carried by the top spring. (ii). A modification, Fig. 2, consists of two springs 9, 9<1> carrying contacts 13, 13<1> which have a rolling engagement and disengagement controlled by the movements of the weighted armature 4 of the operating magnet 14. Switches, actuating by reversal of rotary motion. A reversing switch, Figs. 4, 6, and 7, consists of a friction element M<1> centrifugally mounted upon the dynamo shaft D' by means of sliding bolts M<6>, M' and a counterweight M<8>. The element M<1> is normally pressed by a spring into engagement with a cylinder Q<15>, which is thus rotated in accordance with the direction of rotation of the dynamo, a screwed spindle Q" reversing the switch contacts Q', Q<2> carried by an internally screwed member Q<9>. At a predetermined speed the members Q<15>, M<1> are disengaged by the action of the counterweight M<8>. Contacts.-The contacts of the various switches are made from a compressed mixture of copper or other metal and carbon or plumbago.