[GreenKeys] Magnet Spice Model

[Robert McConnell]

At 5/26/04 02:34 PM, Tim Swarthout wrote:
>Bob
>
>After doing a little research, it appears that the inductance of the
>selector magnets is around 4 H, as incredible as this sounds! I found this
>information in several excellant articles by Ron Guentzler  which appeared
>in January 1968, and May & June 1969 issues of 'RTTY Journal'.
>
>Please report the results of your Spice Model investigation. Thanks.
>
>Over the years, I have seen many model 28 machines, but I don't ever recall
>seeing one with the keyer tube! Isn't that strange?
>
>Regards to all,
>
>Tim Swarthout, WA5QEG

It has been a long time, but my recollection was that the M28 selector 
magnets connected in parallel for 60 ma added up to one Henry. The primary 
reason they needed a 135 V loop with significant resistance was to minimize 
the switching time constant.

Bob McConnell
N2SPP