[Boatanchors] Relay Contacts, etc.

[Ron]

From: mac <w7qho at aol.com>
To: Boat Anchors List <boatanchors at mailman.qth.net>
Sent: Tue, February 2, 2010 1:46:44 PM
Subject: [Boatanchors] Relay Contacts, etc.

> The old (40s/50s) IBM tabulating systems used hundreds of wire contact  
> relays and the circuitry was specifically designed so that the  
> contacts NEVER made or broke current. 

The purpose of that was to prevent contacts from 
breaking a live circuit. That would have caused 
sparking that would have necessitated far heaver 
contacts. 

Another reason was the required timing accuracy. 
Timing was provided by heavy duty circuit breakers,
actuated by the machine motor, thus relays speed 
was never a factor. 

> Timing was such that all relay  
> contacts were either open or closed before current pulses were sent  
> through the logic.  These relays used removable wire contacts on the  
> armatures and special burnishing and other tools were provided for  
> their maintenance.  Does anyone remember the maintenance protocols for  
> these components/equipments?

I think I still  do  :-).

-- Ron




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