ADA Depot - A Forum To Support Users of ADA Amplification Gear
Miscellaneous => Discussions => Topic started by: Micky on July 23, 2014, 07:34:24 AM
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Hi,
what about to put a standard equipment (pre, fx, power amp...) under UPS?
something like this: http://www.powerwalker.com/line-interactive.asp
I suppose it should be a pure sine waveform.
Micky
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Hey Micky, yep pure sine wave sounds good, decoupled is better still (i.e. all feed from battery which gets charged by mains). My experience, MP2s don't like bad power (i.e. shit themselves in the middle of a solo :facepalm: ) so I run a decoupled UPS when I'm running off a generator. Others use power filters. Down side of reasonable UPS is battery dies. But they (UPS) are cheaper than many power conditioners these days (mine AUD $160, Furman AUD $500ish)
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Ok, decided to buy an UPS, pure sine waveform.
My "problem" is to evaluate the size, considering it has to feed an MP-1, LXP-1, MidiVerb, micromixer (4-1), Peavey 50/50.
Suggestions?
550VA/330W can be suitable?
Thanks in advance
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Hey Micky, Rule of thumb is to get a UPS such that the power you need is ~60% of the UPS's spec. So if you need 600VA to comfortably run you rig, get a 1KVA (1000VA) which is what I did. My rig is similar (MP2, Quadverb, Midiverb4, mixer, amp (either carvin TS100, or carvin DCM200L or B200s). I've since added a MB1 as well but I've scoped it for plenty of wriggle room to allow additions.
You can get the power consumption from the units spec sheet (manuals). The old depot gear pages are still available here (http://web.archive.org/web/20040422213430/http://adadepot.com) and you can navigate to the various units.
MP2 uses 35W, MB1 uses 12W (according to their spec sheets)
Conversion site (http://www.powerstream.com/VA-Watts.htm)
The conversion of W to KVA is governed by the equation KVA=W/(1000*PF) If you go with power factor of 0.6 then
So for MP2 KVA=35/(1000*0.6) > KVA= 35/600 KVA = 0.0583 or 58 VA
So you could (Very) conservatively assume each small 1RU effect/preamp style unit is no more than say 60VA. Above I have 5 such units (60*5 = 300VA (with plenty of wriggle room)). My TS100 says it's 300VA, so I need 600VA all together.
You'd most likely get away with a 550VA UPS as your biggest draw is the power amp and my number above have lots of wriggle room. But I'd go for bigger (750VA or better 1KVA) as I have done :thumb-up:
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Cool info, Nolan :thumb-up: I weren't aware of those calculus.
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1 va = W/cos phi (cos phi = powerfactor)
There are 3 kinds of powers, the active power P in Watt, the reactive power Q in VAR (Volt Amp Reactive) and apparent or complex power in VA (Volt Amp)
With a pure resistance va is the same as w but not with an inductive or capacitive load. A pure inductive or capacitive load is all reactive load. If you put an alternating current on these they will draw power and give that power back to the grid. Now this is only for ideal inductors and capacitors, but since these don't exist there will also be a small part of active power since a caps and inductors have a small dc resistance and this small amount of active power will be turned into heat losses.
So what are the differences here. Well active power is the actual power you use and pay for ,the reactive power is power drawn from the grid but it's put back into the grid and apparent power is complex form or sum of the active and reactive power. And the bigger the reactive power is the smaller the power factor is.So if the power factor is 0 you have a pure reactive load, if the power factor is 1 then you have a pure active load.
https://upload.wikimedia.org/wikipedia/commons/8/84/DiagramaPotenciasWPde.jpg
So what's the fuzz about the power factor and the electrical company's wanting to have a high power factor. Well it's the cable's, they have to be calculated on the apparent power since it's drawing the apparent power and it's only consuming the active power.
Let's say you have a electrical motor of 100W with a power factor of 0.7 so it will draw 142.85 VA (100/0.7) from the net but it will return the extra 42.85VA back to the net and consume only the 100W but the wires must be able to deliver that 142.85VA.
Since most loads are inductive company's use banks of caps they put on the power lines to get the power factor to near 1, most cases 0.95. A system will measure this and switch in and out those banks of caps.(caps and inductors are electrical opposite of each other)