apc inverter output
apc inverter output
(OP)
Hi, I want to measure the current output from a UPS. I seem to remember that there is a reason that you can't use a standard current clamp on inverter outputs as it will not give a true reading. I am assuming that the output from the ups will be some sort of PWM waveform? could somebody please remind me of the reasons and indicate how inaccurate the readings are likely to be.





RE: apc inverter output
Keith Cress
kcress - http://www.flaminsystems.com
RE: apc inverter output
RE: apc inverter output
Distortion current will not do much in the way of useful work, unless maybe to a heating element, because for the most part all it does is make things run a hotter. So if your inverter is shown by your ammeter to be putting out 10A, but it is inclusive of of 18% distortion current, the amount of amps you REALLY have to work with may be only 8.2A, because when your loads consume 8.2A of real current, they might ALSO be consuming another 1.8A of added current that is just heating up things with windings in them, such as transformers on power supplies, motor windings etc. The inverter however still has to put it ALL through its transistors, whether it is useful to you or not.
From my experience, APC has never been known for aggressively pursuing quality over price points, so I would not be as hopeful that they would spend the extra money to research the better ways to do it. I may be wrong on that because things can change, but I worked for Sola for a couple of years a long time ago and at that time, we got our butts handed to us by APC, who was selling absolute junk UPS systems, but at prices so low people put on their blinders to buy them at "big box stores" and hope for the best.
"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington