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<blockquote data-quote="Robert Patch" data-source="post: 66524" data-attributes="member: 1402">Re: Surge Supressor vs UPSYou got me wondering how the UPS actually responds to fluctuating voltage.&nbsp; I dug out my variac and calibrated it using a Fluke 87 voltmeter.&nbsp; My line voltage is 123 Vac so I started there and it passes 123 Vac through the UPS.&nbsp; 120 V = 120 V, 115 V = 115 V, 110 V = 110 V, 107.5 V = 107.5 V, 105 V = 105 V, 102.5 v = 116 V.&nbsp; Ah ha, here was the threshold for the battery to kick in.&nbsp; This was repeatable.&nbsp; 100 V = 113.5 V, 97.5 V = 110.5 V, 95 V = 108 V, 92.5 V = 105 V, 90 V = 102 V, 87.5 V = 99.5 V.&nbsp; Then I turned the variac off and it jumped to 119 V.&nbsp; Turned it back on and 87.5 V = 99.5 V.&nbsp; Then I turned the variac up all the way.&nbsp; 141.8 V = 125.4 V.&nbsp; Accuray looked to be no worse than about +/- .5 V.Then I reset the variac to 123 V and started switching it on and off.&nbsp; The interesting thing is that I switch it off and the voltage goes to 119 V and turn it on again and after a couple of seconds it reverts to line voltage, but if I turn it off again, it shuts the UPS down.&nbsp; I did not experiment with how much time would have to elapse for this not to happen.&nbsp; I was switching it off for a few seconds and switching it back on for a few seconds.&nbsp; The indication is that there might be a problem if the power was going off and on again a couple of times in quick succession.</blockquote>

[QUOTE="Robert Patch, post: 66524, member: 1402"] Re: Surge Supressor vs UPS You got me wondering how the UPS actually responds to fluctuating voltage. I dug out my variac and calibrated it using a Fluke 87 voltmeter. My line voltage is 123 Vac so I started there and it passes 123 Vac through the UPS. 120 V = 120 V, 115 V = 115 V, 110 V = 110 V, 107.5 V = 107.5 V, 105 V = 105 V, 102.5 v = 116 V. Ah ha, here was the threshold for the battery to kick in. This was repeatable. 100 V = 113.5 V, 97.5 V = 110.5 V, 95 V = 108 V, 92.5 V = 105 V, 90 V = 102 V, 87.5 V = 99.5 V. Then I turned the variac off and it jumped to 119 V. Turned it back on and 87.5 V = 99.5 V. Then I turned the variac up all the way. 141.8 V = 125.4 V. Accuray looked to be no worse than about +/- .5 V. Then I reset the variac to 123 V and started switching it on and off. The interesting thing is that I switch it off and the voltage goes to 119 V and turn it on again and after a couple of seconds it reverts to line voltage, but if I turn it off again, it shuts the UPS down. I did not experiment with how much time would have to elapse for this not to happen. I was switching it off for a few seconds and switching it back on for a few seconds. The indication is that there might be a problem if the power was going off and on again a couple of times in quick succession. [/QUOTE]

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