GB580100A - Improvements relating to apparatus for electro-deposition - Google Patents

Abstract

580,100. Automatic control systems for electroplating..WESTINGHOUSE BRAKE & SIGNAL CO., Ltd., PETER, L. H., and MACGREGOR, R. M. Feb. 25, 1944, No. 3515. [Class 38 (iv)] Current and switching control.-The control system of an electrodeposition apparatus is arranged automatically to reduce to a low polarizing value the voltage on the electrodes at the end of the plating cycle. A protection relay 23 on closing isolation 2 energizes auxiliary contactor coil 48 by contacts 59. Contactor 48 closes contacts 58. The circuit of the main contactor 5 is completed on closing push button 56 operating main contacts 4 to feed threephase autotransformer 6 connected through the lower normally closed contacts of switch 7 to the primary of a motor driven induction regulator 10. The output from the induction regulator is connected through transformer 13 and metal rectifiers 15 to electrodes 17, 18 in vat 19. Contactor 5 also closes contacts 47 through which current is supplied to change-over contactor 8 and timing device 36, set for the required plating time, on actuating push button 35. The contactor 8 closes the upper normally open contacts and opens the lower contacts of switch 7, applying the normal plating voltage to the vat. A control ammeter 31 maintains the plating current between high and low limits by means of contacts 30, 29 energizing the motor 24 of the induction regulator. A thermostat 52 prevents overload of the rectifier by tripping contacts 51 in the auxiliary contactor circuit thereby energising the main contactor 5. When contactor 8 is de-energized by device 36, are-set circuit comprising contactors 38, 42 is energized to prevent the full plating voltage being applied to the electrodes until re-set switch 39 is operated. To indicate failure of supply, overload and incorrect plating ' current lamp circuits are provided. A stand-by battery supply 71 maintains low voltage on the electrodes should the main supply fail. A recording panel for pH, and direct-current and voltage may be provided. Re-set switch 39 may be remote from the rest of the controls to be operated by a supervisor.