>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 _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
