[time-nuts] DC-DC converter

GandalfG8 at aol.com GandalfG8 at aol.com
Sat Sep 26 16:19:42 UTC 2009

In a message dated 26/09/2009 15:40:29 GMT Daylight Time,  
james.p.lux at jpl.nasa.gov writes:

Of  course, another problem is that the Z3801A doesn't use 48V. It takes  
voltage, from K8CU's site: The Z3801A is specified by HP (depending  upon
model) as  either a nominal minus 54 or plus 27 volt device. The  best bet
is to keep the voltage at the nominal value specified by HP.   This way any
out of specification internal DC to DC converters  are  satisfied, and the
units will perform normally. Reports  from other  users confirm this.

Most Telecom supplies do seem to be around the -54 volt mark, the one I use 
 for the Z3801A is a bit lower than this at  -55.1 volts, but the Z3801A  
itself is marked 38 to 60 Vdc.
Whilst the HP Specification, as per page 5-4 of the manual, is -54 Vdc  
nominal it does then go on to clarify this as being.....
-60 Vdc +/- 0.5 Vdc to -37 Vdc +/_ 0.5 Vdc operating range, less than -46  
Vdc +/_ 0.5Vdc starting.
As expected from the above, PSU problems tend to be more noticeable at  
startup if higher voltages, ie closer to zero, are used but a regulated -48  
volt supply should be fine.

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