1122 THE BELL SYSTEM TECHNICAL JOURNAL, SEPTEMBER 1953 



Control of the output of the entire bank of rectifiers of the acid copper 

 plate section is accomplished through the associated induction voltage 

 regulator. Individual adjustment of load and compensation for aging of 

 the rectifier stacks has been provided for by bringing out to terminal 

 boards within the housing a number of leads from the primary windings 

 of the rectifier transformers. For a given feeding voltage, the output of 

 each rectifier can be adjusted over a considerable range by the position- 

 ing of jumpers at the terminal boards. Except for aging compensation, 

 this adjustment, once made, need not be made again. Control of the 

 output of the "auxiliary" rectifiers is accomplished by tap-switching, 

 under load, between taps brought out from open-delta autotransformers 

 on the primary side of the rectifier transformers. 



The capacity of the bank of the sixteen rectifiers feeding the acid 

 copper plate section of each machine is larger than is actually required 

 to produce the wire. With this additional capacity distributed among the 

 rectifiers, it is possible to continue plating operations in case of failure 

 of one rectifier. The automatic control system will increase the output 

 of the remaining fifteen units immediately after the one has dropped off 

 the line. 



The bay in which all rectifiers are located is separated from the 

 operating bay by a plaster partition which serves the purpose of forcing 

 the incoming fresh air flow past the rectifiers protecting them from any 

 corrosive atmosphere which might be present in the operating bay. The 

 rectifiers are placed against the wall and their bus terminals ex- 

 tend through small apertures into the operating bay. Because the op- 

 erating bay floor level is about two feet higher than that of the rectifier 

 bay, the rectifier terminals emerge from the plaster partition below the 

 floor elevation of the machine. This permits the running of the busbars 

 out to the machine by passing them under the operators' walkways. 



These feeder busbars from the rectifiers terminate beneath the section 

 of the machine which they are to feed. Flexible laminated connectors 

 join the feeder buses with the buses running longitudinally under the 

 machine : from the longitudinal buses additional flexible connectors carry 

 the current up to the rigid terminals leading into the plating cells or up 

 to the copper castings supporting the brushes and contact rolls. 



The dc circuit, both inside and outside the rectifiers, has been com- 

 pletely insulated from ground excepting that grounding caused by elec- 

 trical contact with the wire itself. Stray currents are thereby minimized 

 and kept out of pipe lines or building steel. 



All of the busbars used on the machine are of the square drawn copper 

 tubing type. Aluminum was considered but rejected because of the seri- 



