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Remember UPS's will generally only run for about 30 minutes or less. You will spend a lot of money if you start getting extended runtime batteries. You might want to look at a generator instead if you are looking at rolling blackouts lasting a few hours.
Imagine if i have a 1500 VA ups
and i have 6 screens using 40 watts = 240 VA (watts)
will the UPS stop after 30 minutes ?
please explain ? i missed something...
If you are running a standard UPS (Cyberpower, APC, etc) with a standard battery, you'll only get about 20 to 30 minutes of power from them. They are designed to allow you to get your machines shutdown and save your work not to run your systems for hours.
If you want something that runs much longer, you'll need to spend much more money for extended UPS' or a generator.
from the little of information available
we have been told
black outs could be +/- 3 hours
what sizing do you propose ?
my screens 6 X 40 watts, taking some marging = 300 VA /hour
if i want them to run 3 hours, what UPS do i need ?
not 900 but ?? how much ?
(i'm learning)
or just minimal, 15 minutes to get a 20 KVA generator running ?
and enlighthneing the complete building (which was not my thinking)
Size isn't the solution. You would either need several extended runtime batteries (expensive), or what I would recommend is a generator.
I just purchased a whole house generator, Kohler 14kw, for $3500. And it will run your house as long as you keep it full of fuel (in my case, propane). You can find diesel or propane or natural gas generators for whole house (connect to circuit breaker). If that is too extreme, then look into portable gasoline generators. I bought one of those as well recently, 2.5kva for $299. Enough to run my office as long as I keep the tank full.
I advise that you ascertain/calculate your total power need in WATTs or KVA.
The options are
1. Extended UPS
Considering that I don't use the UPS anymore, I don't have any info on UPS.
2. Generator
Generators are really not meant or designed for constant/daily household use or even office use.
In this part of the world where I reside, it is menacingly and daily used in nearly every homes and definitely in every office buildings, because the power supply from the national grid had completely broken down over the years (more than 30 years) without solutions. Generators produce fumes/smokes/smells and horrible noise, thus polluting the environment; fumes and fire incidences from generators usage have caused death to several people; the cost of fueling, repairs/maintenance is unavoidably high.
If you must buy a generator, go for the diesel-powered types. Diesel fuel are not flammable like gasoline or propane, but the fume from diesel powered generator is horrible.
3. Inverter/Charger system
I already had a post (post #9 above) on this, four years ago (2010).
The cost of my Inverter/Charger system(including Installation fee and Circuit Breaker) is $2,147.00 (converting from my local currency to US dollar ... $1.00 = N163.00). The system was installed in 2009. So, for these past years I did not effectively have the need to buy fuel (diesel in my own case). Until recently, there was no need for repairs and maintenance (I'm now planning to buy a new Inverter/Charger system). Also, there has been no messy fueling, no fumes/smokes, no noise, no dangers of the possibility of fire incidence (especially in the case of gasoline). I still kept my 7KVA generator in case of a long run-down of the Inverter/Charger batteries. The cost of the generator is $1,104.00.
If you have a budget of $3,000.00+, go for an Inverter/Charger system.
Another value-for-money approach is to increase the capacity of an off-the-shelf UPS with a larger battery pack. UPS manufacturers charge an incredible amount of premium on their batteries themselves rather than the circuitry of the UPS. A common trick is to replace/supplement the batteries with car batteries, which have higher capacity per dollar.
There's a few guides online on this if you do a Google search and several articles have reported safely getting 1+ hour uptimes.
Disclaimer: Note that this trick has a limit, because prolonged hysteresis in the UPS transformer will eventually lead to overheating, and some UPS components are not thermally designed to be running for hours. Proceed with caution.
I personally think that a fuel-based generator is a dangerous fire hazard. A safer alternative is to use a nuclear reactor for your backup power, with U233 as a fissile fuel.
To keep a generator at 1.4 kW average load for an hour consumes/produces about 5.04 MJ (ignoring efficiency factor). The calorific value of petrol is about 94.0 MJ/m^3, which means you'll consume at least 13.2 gallons of petrol per hour. (Kohler's technical specs suggest a much larger number here: https://www.kohler.com/en/home-energy/home-generators) I wouldn't leave so much petrol lying around in my garage in a naked storage tank!
There's also a few guides out there on building your own nuclear reactor, but here's important points that are usually missed:
- An incandescent gas mantle should carry about 0.2g of ThO2, which is ideal for neutron capture while remaining inert in room conditions.
- Moreover, the Th particle in ThO2 has a large neutron absorption cross-section, which makes life easy for you as you need not reduce it against pure calcium, since calcium has to be purified by electrolysis of molten calcium chloride. I estimate 0.2g of ThO2 should yield about 12.7 kWh of heat energy as a fissile fuel.
- There was one failed case where a high school student tried to reduce ThO2 against lithium - Li is a group I metal and so is less stable; I would recommend calcium and in either case, reduction of ThO2 is not necessary due to the neutron absorption cross-section of Th.
- Then, I recommend you use paraffin wax blocks for shielding against your neutron source. Neutrons are not deflected by electric fields and so pass through almost anything and are more hazardous than low (<5 MeV) and high-energy (>20 MeV) gamma radiation. Lead shielding is important for the later steps.
- You need an alpha particle emitter, e.g. americium (found in smoke detectors), put it together in a granular mixture with graphite (beryllium is preferred, but graphite is easier to obtain), will act as a reasonable neutron emission source.
- Subsequent, spontaneous emission in your thorium sample eliminates the need for the neutron source to breed U233.
- After this, the reactor design is pretty straightforward (closed-loop water heating).
It's much easier to store 0.2g of thorium dioxide, which will give you 9 hours of backup power, as compared to 119 gallons of petrol.
It's 'solved' in our country as the financial houses got hold of the subsidy schemes. Now taxpayers have to pay the windfarms 3X-5X normal rate to keep them switched off at overload times...
It will still go dark and cold though, that's just a matter of time. Incompetence and entropy are hard task masters.
Our government just concluded the privatization of the power and energy sectors/industries a few months ago, this year. The sectors/industries had always been 100% under government ownership and control.
It seems unbelievable to note that within the past three weeks, the power supply from the national grid, in my country is nearly constant at 24/7. We still consider this as an amazement 'cos we had virtually consigned ourselves to a situation of helplessness. This new development should make my Inverter/Charger system serve me better during very few hours of blackouts, when they occur.
