CARD TRANSLATOR FOR NATIONWIDE DIALING 



1091 



The pull-up magnet is capable of exerting a pull of 350 lb when the 

 airgap is 0.020'' which is approximately 25 per cent more than the nor- 

 mal operate gap and since the cards weigh approximately 100 lb. it will 

 be seen that a reliable operate margin has been provided. The perform- 

 ance capabilities of the pull-down magnet were developed in the dis- 

 cussion of its effect on the drop time of the cards. The breakaway pull 

 of this magnet is approximately 1,000 lb. 



LIGHT SOURCE 



The light source comprises the projection lamp, the light beam modu- 

 lating wheels, the wheel driving motor, and the two first surface mirrors, 

 as illustrated by Fig. 18. The mirrors direct light from either side of the 

 major plane of the lamp filament via the dual collimating lenses and the 

 card stack formed light tunnels to the photo- transistors. Various ad- 

 justment and supporting details are combined in a subassembly il- 

 lustrated by Fig. 36. The subassembly is shown mounted on a fixture 

 that is used during manufacture. 



The lamps usually can be interchanged without readjustment of the 

 mount or the associated components. At the most, all that has to be done 

 is to orient the lamp so as to obtain reasonable alignment of the major 



MODULATING 

 DISC 



MOTOR 



PROJECTION 

 LAMP 



CHIMNEY AND GUARD 



Fig. 36 — Exciter lamp assembly. 



