[GreenKeys] wire spring relays

[Don Robert House]

Hi Charles,

I think the relays in question may have been used for coin telephone  
collect and or return.  I will forward your message to my switcher"  
buddy who knows this stuff.  Doug Alderdice may also know more than  
my guessing.

Don


On 25 Jan 2006, at 10:04 AM, Charles Ring W3NU wrote:

This is not directly related to TTY but I know there are a number of  
Bell Telephone veterans here, so...

I recenty bought on ebay 60 pounds of W.E. wire spring relays, which  
I have used for years for broadcast audio switching. The best relays  
in the world. This lot consists mainly of 4 rack panels, each with 8  
dual relays, each side of each relay having five form C contacts  
(ideal for my purposes). My first surprise was that each side of each  
relay has a soldered-in 1200 ohm 1 watt resistor in series with its  
coil, and the coil resistance is only 90 ohms, using magnet wire  
heavier than usual. It takes about 90 mA to pull in the armature, and  
the biggest surprise was that upon removing the current the relay  
stays pulled in, indefinitely. It takes a current pulse of opposite  
polarity, less than it takes to pull it in, to release the relay.  
I've seen delayed-release relays before but not this. I see nothing  
physically obvious to make them behave this way. Each side of each  
relay has a number from 0 to 15 stamped on it, so I guess what I have  
is four hexadecimal magnetic memory units.There are no SD or BSP  
numbers on any of this.

1. Is my guess right that these are memory relays and I could  
reliably use them as such? Do they stay pulled in long-term?

2. Is there any way to change them to normal relay operation?

3. How are they made to behave this way? Some magnetic material that  
stays magnetized long-term? I don't have a normal dual relay to  
compare them to on hand.

4. Is there another list or forum where this subject would be more on  
topic?

Thanks and 73 de W3NU



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