[GreenKeys] Current limiting

[Don Robert House]

25-50 watts in series with a fixed resistor for shorter loops.

Don
K9TTY

I can send images if someone wants them.


On 19 Jan 2009, at 6:09 PM, Bob McConnell wrote:

Larry Tighe wrote:
> Howdy Folks,
>
> what limits the current in the WECo power supply under the TTY  
> machine to 60
> ma.?  Is it the ferro resonant?  This p.s. is very quiet and I don't  
> have a
> print on the box....model 12 power supply I think.
>
> lar
> Larry
> www.antiquetelephone.com

Hi Larry,

The circuits I was familiar with all used a big honking rheostat in the
loop. Usually the loop supplies were about 135V DC with very low
impedance. The rheostat was adjusted to 60 ma each time we added or
removed a machine from the loop. I believe they were 5 watts each, but
they may have been more.

Bob McConnell
Ex-RM2 USN - NFIT, NLM
N2SPP
_______________________________________________
GreenKeys mailing list
GreenKeys at mailman.qth.net
http://mailman.qth.net/mailman/listinfo/greenkeys