[GreenKeys] Basic question

[Randy or Sherry Guttery]

Dave, KV4CN wrote:

> Just got a model 28ASR 
> and will use with an ST-6.  The ST-6 loop voltage is 175 volts.  What I 
> have seen in the literature is a range of 120 to 150 volts.  Is 175 too 
> much for the M28?

What primarily matters to the 28 is the current - which (for normally 
connected 28s) should be 60ma.  While 175V is a tad high - it's still 
below the filter component ratings of the 28's keyboard. With whatever 
voltage source you use - you need to ensure that the keying loop is 
limited to 60ma... (the danger of higher voltages in that regard is 
overheating the selector magnet windings should the loops total 
resistance not be enough to limit to 60ma - so monitoring that is a good 
idea).

best regards!
-- 
randy guttery

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