Patent GB-506032-A (GB)
Title: Improvements in or relating to electric distant control apparatus
IPC: G05D3/14
Filed: 1937-11-13
Abstract: 506,032. Electric control systems. JAPOLSKY, N. Nov. 13, 1937, No. 31239. [Class 40 (i)] In a control system which is " monoperiodic " i.e. wherein there is only one stable relative position between the transmitter and receiver, the transmitter and receiver are associated with potentiometers capable of effecting coarse and fine adjustments of the receiver. The systems is described with reference to a system of the type set forth in Specifications 466,881 and 466,952 wherein a " monoperiodic system is employed to maintain exact synchronous working of a system which is " poly-periodic viz. a system in which the receiver has several possible stable positions relatively to the transmitter. Fig. 2 shows a " poly-periodic " transmitter 21 controlled by a handle I and connected to a receiver 24 over connections 22, 23 which may include an A.C. commutator generator (not shown). The transmitter is associated with the handle 1 through a differential mechanism 20 which is also controlled by a D.C. motor 26 which is normally locked in position by current supplied over the leads 28. The motor 26 is unlocked when a discrepancy in the relative positions of the transmitter and receiver occurs and is controlled by a generator 105 which has field windings 106, 107 energized in accordance with the discrepancy and the relative speeds respectively. Operation of the motor 26 introduces into the transmitter through the differential mechanism a correction which ensures synchronous operation. Potentiometers 2, 3 are provided at the transmitter and receiver respectively, the contacts 4 ... 9 of which are adjustable by the handle 1 and the receiver 24 respectively. The pairs of contacts 4, 7; 5, 8; 6, 9; are connected to coarse, medium and fine adjustment relays 35, 36, 37, Fig. 1, and the sets of contacts 4, 5, 6 ; 7, 8, 9 are geared together with a velocity rate of say 1 : 12 : 144. In operation when alignment between the transmitter and receiver 21, 24 is lost a P.D. is developed between the " coarse " contacts 4, 7 and relay 35 is operated to apply the P.D. to the field winding 106 of the generator 105 over the contacts of a reversing relay 102, 103, and cause operation of the motor 26 to apply the correction. The relay also connects the winding 107 across the armature of the generator to introduce the correction due to the difference in speeds of the handle 1 and the receiver 24 and renders the operation of the medium " and" fine " adjustment relays 36, 37 ineffective. When the receiver position is corrected within the step of accuracy of the coarse adjustment as determined by the contact tappings of the resistances 2, 3 the relay 35 releases and causes the " medium " P.D. at contacts 5, to effect a control in a manner similar to that previously described and when adjustment is made within the limits of accuracy of the medium transmission the fine control is switched in to effect the final correction. In, order to ensure that the receiver is operated in the correct direction by a subsequent control stage within the limits of accuracy of the preceding stage, the transmission step of the subsequent stage corresponding to the total voltage range is made at least twice the step of accuracy of the preceding stage. This ensures that the reversing relay 102, 103 is operated to reverse the direction of operation if the P.D. produced by the subsequent stage is more than half the maximum voltage. The contacts 4 .. 9 may co-operate with individual commutators connected to tappings on the resistances; alternatively individual resistances may be provided. In modifications, the relays 35, 36, 37 may be replaced by a commutator switch and a plurality of batteries may be used instead of the resistances; furthermore, the resistances may have a non- rectilinear characteristic gradients.