[GreenKeys] Re: Driving Selector Magnets

[Don Robert House]

EXCELLENT information Robert.  You do a great service to this list.
Don

P.S.
I found a source for the one stuffing tube the -006.  Now to find  
three of the -005 and I will have everything to complete the three  
interconnection boxes.


On 17 Apr 2007, at 6:50 PM, WA5CAB at cs.com wrote:

Brooke,

This has been discussed (and cussed) here several times in the past  
year.
But the short answer is that if you run the loop from say 24 VDC,  
which is high
enough to put 60 mA through the selector magnets (usually, anyway), the
current rise time when going from Space to Mark is so long that the  
Selector Range
goes to zero.  And the error rate goes sky high.  When you run 115  
VDC and an
adjustable resistor, the resistor swamps the inductance and you get  
nearly a
square wave (current) through the magnets.  And the machine is happy.

Historically, 115 VDC was chosen because some of the motors were 115  
VDC as
well.  So you could run the entire machine from one generator.

Robert Downs - Houston
<http://www.wa5cab.com> (Web Store)
MVPA 9480
<wa5cab at cs.com> (Primary email)
<wa5cab at houston.rr.com> (Backup email)

_______________________________________________
GreenKeys mailing list
GreenKeys at mailman.qth.net
http://mailman.qth.net/mailman/listinfo/greenkeys