[time-nuts] UPS for my time rack

[Bill Hawkins]

>From experience, here's a story about a very quiet (RF-wise) pretty good
sine wave UPS device.

I acquired a Liebert 2KVA UPS for data centers in 1999 when our division
was declared redundant. The cost when new would be prohibitive, but this
one was junked when it stopped working. I got it, found a bad
electrolytic cap (from the stains) and replaced it. Worked well. Never
did get a manual, had to trace the switching stuff.

This was from the days when data centers could afford the best in
immortal power. The line feeds a regulated DC supply that runs the sine
wave inverter and maintains battery charge. The inverter runs in sync
with the line, but a relay connects the line to the load while the
inverter idles. When the line fails, batteries supply the inverter and
the relay switches it to the load. Then a cooling fan starts up.

This machine required eight 12 volt batteries for 96 VDC nominal, higher
on float charge. I bought 15 amp-hour batteries and wired them to a
connector on the back intended for external batteries. Lethal voltage,
of course. Requires proper protection.

Also had a line voltage relay and toggle switch that would bypass the
UPS and connect the time rack directly to the line. This allowed the UPS
to be replaced when its warranty ran out. Batteries lasted six years,
did not invest another $500 in them.

Good luck.

Bill Hawkins


-----Original Message-----
From: Chris Waldrup
Sent: Saturday, October 10, 2015 8:20 AM
To: TIme Nuts
Subject: [time-nuts] UPS for my time rack

Hi,

I have decided I'd like to get a UPS to put on the rack containing my
Thunderbolt, the laptop that runs Lady Heather, and frequency counter.
Has anyone had bad experience noise wise with the APC brand units like
are available on Amazon and at Staples? I'd like to get one that doesn't
generate lots of RFI. Thank you. 

Chris
KD4PBJ