This is a trick answer, and don forget your power factors.
Computer draws 450 watts, printer draws 1.5 amps, monitor is 1.5 amps and your constant is 120 Volts AC. Your Power factor is .778
I want 60 min. run time full load.
What is the cheapest route.?
2007-02-07 14:30:21 · 3 answers · asked by John P 2 in Science & Mathematics ➔ Engineering
It is a simple question that requires some thought. Most people when they buy back up power for their computer have no idea how to properly size their UPS for the equipment they have. Most people go out and buy the cheapest thing out there, but wonder why they don't last six months. So an Engineer, will be happy to try and figure this out. Ohms Law, Power Factor, is you only tool to figure this out. I did forget one thing. What ever the VA value you come up with, remember when the inverter starts up, you loose 50VA based on induction, but the total value of your VA value = 15 min of run time for your load capacity.
2007-02-07 14:47:45 · update #1
Nice try with the Cyber Power 1200VA, and you are on the right track, but no, that is not the right answer. The 1200VA stand alone, will only give it 20 min run time. The Printer is rated at 1.5 amps, so it matters not, what name brand, rather the amps consumed. Some one will give the right answer. Keep trying.
2007-02-07 16:07:57 · update #2
You can see I am giving you hints. It is amazing out there how many people never thought about this very important product we have taken for granted, and yet, we never take the time when we buy these things to truly figure it out. What is really sad, even the manufacture technical staff are ill equip to do simple math.
2007-02-07 16:13:27 · update #3
Nope, 1300 is not right. I said for 60 min. not 20 min.
I will have to give you another hint.
If you have 20 min. at 1300VA, how many times does it take in VA to get 60 min. Dah?
2007-02-07 17:34:02 · update #4
Nope, 1100 is not right. I said for 60 min. not 20 min.
I will have to give you another hint.
If you have 20 min. at 1100VA, how many times does it take in VA to get 60 min. Dah?
2007-02-07 17:37:21 · update #5
usually for home systems( include main' monitor' home printer' scan' and ...) we consider 450 up to 500 watt capacity of ups but according to your load spec. the UPS with 1100VA capacity is OK. (1100* 0.778=855 watt=(450+(3amp*120)=810) but this is not normal range in market so you can buy a 1300 VA .
2007-02-07 17:20:47 · answer #1 · answered by omid 1 · 0⤊ 0⤋
CyberPower CP1200AVR 1200VA 720W UPS - Retail $115.00.
What type of printer? This will affect your PF.
Enjoy
2007-02-07 22:59:49 · answer #2 · answered by Anonymous · 0⤊ 1⤋
i dont get your question :-/
2007-02-07 22:39:16 · answer #3 · answered by Zackery 2 · 0⤊ 0⤋