I know this is an old post, but my fuzzy math skills are still a little off.
I wish to maximize the 1800W limit on the UPS inlet for the UTS10BI. If I used an APC SMT220 would I be okay? I know that its rated output is 1920W, but if I move down to another model then I can't utilize the full 1800W capability on the UTS10BI input. Comments and suggestions are appreciated.
hello. i think there is a little mistake here on the UTS's part unfortunately.
the convenience outlet on the UTS10BI for the optional UPS is 5-15R. the plug on an SMT2200 is a 5-20P and will not fit into a 5-15R receptacle. the 1800 watts is also a little misleading. 5-15R indicates an 120V receptacle rated at 15 amps. 5-20R is a 120V 20 amp receptacle. if we take 1800 watts and divide it by 120V, that gives us 15 amps. basically, i think someone made a mistake here with the calculation for the wattage in the UTS because a 5-15R is 15 amp receptacle but national electrical code here in the UPS de-rates it by 20% to 12 amps (that de-rating rule is outlined in article FA157467 in our knowledge base @ www.apc.com/site/support/index.cfm/faq/ ). thus, to get the max wattage this receptacle could provide, we should do 12A multiplied by 120V which gives us 1440 watts. then you also need to worry about power factor when choosing a UPS because all of our UPSs that have a 5-15P will max out at 1440 volt amps (VA) but their actual power output in watts is a little less due to the power factor of the UPS. power factor is the ratio of volt amps (apparent power) to actual power (watts).
hope i haven't confused you but technically, you cannot use a UPS with more than 1440W output with 5-15R that is on the front of the UTS because if you even changed the plug on your SMT2200 to plug it in, you're effectively wasting part of the UPS power output. changing the plug de-rates it to the 1440VA. If our UPSs had a power factor of one, then the VA rating would match the watts rating but none of the Smart UPS have that. There is some info on de-rating when you change a plug listed in article FA156517 in the knowledge base too.
essentially, to get the max you possibly could (1440W), look at something with a 1500VA rating and check the wattage rating of it as well. the ratio between that VA rating and watt rating you see listed on our web pages is that power factor ratio and essentially is what is lost through heat dissipation and in UPS operation. if you or any of the other readers want more information on power factor and watts vs. VA), article FA157485 covers that.
I suggest BR1500G, BX1500G, SMT1500, SMX1500, etc depending on what features you want in a UPS.
Thank you very much and, no, the answer does not confuse me. It all makes sense now. I really appreciate the detailed answer and I certainly love the product.
1. Yes - because of the receptacle type on the UTS. It is a 15A receptacle but per National Electrical Code, a circuit must be de-rated to 80% of its capacity. The 1800 watts assumes 100%.
2. The numbers in the model numbers of most UPSs indicate the VA or Volt Amps. Because of efficiency and power factor on the UPS itself (which most UPS models, especially smaller ones, do not have a unity power factor), you'll see a difference in how many volt amps versus watts a UPS could provide. The way to size a UPS would be watts since that is your "real power" versus volt amps which is "apparent power."
3. If you can find a UPS that has a 15A plug (de-rated to 12A per NEC) and outputs 1440, yes, you could use it. The UPSs around this size we offer would either be Back UPS or Smart UPS and we'd have to see which one offers the best rating. The smaller the difference between watts and VA, the more expensive it will likely be. A value type Smart UPS (http://www.apc.com/resource/include/techspec_index.cfm?base_sku=SMC1500) does 900 watts if you take a peek. We also have either SMX1500 types or SMT1500 types but SMC1500 is cheaper and doesn't have as many bells and whistles as those Smart UPS.
4. Refer to #3
Hope that helps!
Thank you, I love your explanations, they make sense.
Choose a location