[GreenKeys] Current limiting

[Bob McConnell]

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