[time-nuts] The home time-lab

Brooke Clarke brooke at pacific.net
Sun Jul 24 20:02:22 EDT 2016

Hi David:

Yes, the computer, monitor, and DSL modem, switch, answering machine &Etc were connected.
I haven't remembered how to run the DSO in the short time the self test lasts.
AC VRMS line= 117, AC VRMS UPS = 114.

Have Fun,

Brooke Clarke
The lesser of evils is still evil.

-------- Original Message --------
> On Sun, 24 Jul 2016 14:45:02 -0700, you wrote:
>> Hi Bob:
>> The Sola 500 VA transformer is specified to hole up the line voltage for 3 ms.  (but not a half cycle of the line
>> frequency).
>> I've connected the Sola CVS transformer to the output of the APC RS1500 backup UPS.  (needed to replace the 2 batteries
>> in the main unit and probably within a year the 4 batteries in the optional battery pack.
>> http://www.prc68.com/I/Sola_CVS.html
>> http://www.prc68.com/I/PC.shtml#Backup_UPS
>> The Sola transformer is connected to the output of the RS1500.  This will clean up any spikes or narrow drop outs on the
>> AC line since when the AC line is active the UPS does nothing.
>> My hope was that the transformer would clean up the modified square wave output of the UPS, but that does not happen.
>> Video of APC self test showing waveform on scope:https://youtu.be/DLE0mzAt7KY <https://youtu.be/DLE0mzAt7KY>
> Was the Sola transformer under load when you ran the test?  I thought
> a minimum load was a requirement for proper operation.  Maybe it is
> time to get an online UPS or power conditioner but then you would not
> need the constant voltage transformer.
> Was the peak voltage still 170 volts?  If so then maybe it does not
> matter.  Capacitive input loads and PFC power supplies should not
> care.
>> I think the modified square wave killed my HP 6200 flat bed scanner.  The best scanner I've used and no longer made.
> Ouch.  That is not suppose to happen but apparently some switching
> power supplies have problems with modified sine outputs even though
> they should not.
> I have been told a couple of times that PFC power supplies are even
> more likely to have problems with modified sine inverters but I have
> yet to find an in depth discussion of the problem.  The PFC stage
> should work with any input wave shape.
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