ELECTROFORMED CONDUCTOR FOR TELEPHONE DROP WIRE 1109 



points on their characteristic curves so that they perform aUke under 

 speed and load fluctuations. 



The finishing leg rolls and the take up capstan are driven with a single 

 motor identical to the motor driving the supply capstan and the prepa- 

 ration leg. The take-up end capstan adds only slightly to the wire tension 

 over and above that produced at the take-up spools. For that reason 

 the take-up capstan alone does not load the drive motor enough to make 

 it perform like the other motors under load and speed changes. To build 

 up the load on this motor to where it performs at a point on its charac- 

 teristic curve corresponding to the other motors and "follows" properly 

 it is made to also drive all the contact rolls in the finishing leg. 



The take-up end capstan at the exit of the plating line, in conjunction 

 with the take-up spool is fundamentally the tension establishing means 

 for the entire plating line. 



From the take-up capstan, the plated wire is passed back to the 

 main floor over another fanning section, and through guide tubes to the 

 take-up spools. While the take-up capstan may be said to establish 

 tensions for all of the plating line up to it, it is the take-up spool drive 

 which basically originates and determines the order of wire tensions for 

 the entire machine. Any tension increase or decrease originating at the 

 take-up spool is reflected all the way back through the machine to the 

 magnetic supply capstan (Fig. 4). 



On the electroforming machines wire tension control is quite impor- 

 tant. If tensions become too low, the wire may intermittently lose con- 

 tact on the rolls, sag or weave in the plating cells enough to disturb the 

 spacing between the wire cathode and the anode bed in the cell, or actu- 

 ally staU or hesitate long enough to be burned in two at a contact roll. 

 On the other hand, if tensions are permitted to become too high, the 

 tight wire produces excessive wear on the contact rolls, and bruises or 

 scrapes the relatively soft thin lead and brass plate on the wire. For 

 these reasons the wire tensions developed by the take-up spool drives 

 must be controlled within narrow limits. 



The power required to drive a take-up spool is practically constant 

 from an empty to a full spool, but the rotary speed of the spool must 

 decrease as the spool fills up, while the driving torque must increase 

 to compensate for the increase in winding radius. The take-up spools 

 are therefore individually driven with compound-wound dc motors which 

 automatically slow down as the spool fills up, meanwhile holding wire 

 tensions between 15 and 20 pounds from start to finish of a spool. 



All the plated wire produced from a 450-pound core wire supply is 

 taken up on one spool to eliminate intermediate wire cuts, and to produce 



