Choosing the correct ups.

[Gnome]

Same UPS I was thinking of getting...

Specs also look good to me. It's also supported by Windows/Linux/FreeBSD/Open Solaris.

You can ignore this guy's comment. That person doesn't understand VA ratings and also doesn't understand that APC also use VA ratings and that it is actually important.

Also notice on that UPS the external battery connector. You can run external batteries to get longer up time. Usually deep cycle boat batteries (looks like a car battery except it is deep cycle) work best and you can usually get some for pretty cheap. Checked a month ago and 100Ah 12v boat battery was R1K at Midas in Bronkhorst spruit while we were there (to get a new battery for V8 boat ). You'll need two however (24v input on the UPS) but that would give you 24v @ 100Ah which should give you around 4 hours on your setup at maximum load. Probably 8-10 hours on low/idle load.

 

[Drunkard #1]

I dont have much time on my hands these days, busy expanding our shop, and doing most of the work myself, thats why the late response. I really think we must get such a descent ups as you stated here. May I ask how much you paid for it? Or can a dealer maybe quote me? Thanks.

I bought mine years ago. The first one was from Square One, the second from Diesel Electric, and my next (in March) will probably come from one of the online retailers. Look at the dealer locator page on APC's website and phone all of them, then Google for the best online price. Buy the cheapest; I mean, you're in for R 20 000 - 30 000 so if you can save 20 % by shopping around, why not.

 

[blue-eye-boy]

you're in for R 20 000 - 30 000 so if you can save 20 % by shopping around, why not.

Good heavens! Didnt think it will be that much. Maybe i must settle for less. What size must i look for? And what must i check for so i can add bateries later?

 

[Drunkard #1]

Good heavens! Didnt think it will be that much. Maybe i must settle for less. What size must i look for? And what must i check for so i can add bateries later?

This is the cheapest I find in the last five minutes. The 3kVA is R 12 000 without any extra batteries, up to R 27 000 for a 6kVA with 1 extra battery. You need to see how long the basic unit lasts, and how long you need it to last for your genie to kick in, then decide how many extra batteries to buy. The SUA series is also a great product, but I wanted the very best because I've had el cheapo UPSs kill power supplies before, and they're not much cheaper than the SURTs. Also, these come with a network management card that's worth about R 3 000, that does all sorts of fancy things, like sending emails and logging temperature and humidity and voltage etc, etc, etc. Maybe get a quote on a unit without the card.

Remember that this all excludes your sparky's fees. If you really want to do things right, you'll need a circuit breaker for each socket, otherwise a vacuum tripping a circuit (as it should, you don't want vacuums on your clean supply) will take out whatever computers are on that circuit. Plus cabling, plug points, boxes and labour. It's not cheap doing it right, but all it needs is a few days of staff working during power outages, and it pays for itself.

Edit: the 5kVA comes with the management card as standard, the 3kVA doesn't.

 

[Pada]

I can really tell you that it is worth while to get these expensive APC units if you're running servers with valuable data on them.
Like in this week we had a power issue at our complex and when the UPS's reached low battery levels, the servers automatically shut down and came on when the AC power was back on again.

When I worked at SSI, the desktop PC's all had their own cheap UPS's. My cheap Proline 600VA UPS often doesn't switch fast enough to battery power, so then my PC switches off in any case.

Just make sure to install dedicated electric sockets that are meant for PC's & monitors only. These sockets have flat tops that only take dedicated (red) plugs like this: http://www.gapdistributors.co.za/images/Plugtop Janus Bedswitch/Plug2.png
If you don't install those, you will get a cleaner that will plug in her 2000W vacuum cleaner in the UPS, which could damage the UPS, depending on if its in-line or line-interactive when the AC power was lost.

 

[Gnome]

Good heavens! Didnt think it will be that much. Maybe i must settle for less. What size must i look for? And what must i check for so i can add bateries later?

Esquire also sells Apollo online UPSs, they have a 3000VA/2100W unit for R4K incl.

In terms of UPSs online are the best when it comes to protection. They always run from the battery and when there is power the battery is charged. So if the power goes out you don't have switch over delays and no matter what happens on the utility side your equipment is always protected. There are however draw backs, firstly they are much more expensive and secondly they are less efficient because unlike Line Interactive UPSs the inverter is constantly running and they also have fans constantly running to keep the UPS cool.

That Apollo unit comes with 8x12v, 7Ah batteries which would give you about 20 minutes at the UPS's maximum load (2100w) before the battery runs out. However if you don't mind how it looks you can buy off the shelf deep cycle car/boat batteries and just wire them but they wouldn't fit inside the UPS (hence it won't look nice because the batteries and wires are outside the UPS but it'll work 100%). If you bought deep cycle 12v, 100Ah batteries (8 of them, at 1K ea) that would give you 4.5 hours at the UPS's maximum load.

You could also run all the PCs you mentioned above and POS equipment (Visa + tills) + inkjet printer from that UPS. Still wouldn't connect the laser printer tho.

Otherwise you'll have to spend R8K+ on an APC unit. I asked before and no-one had anything bad to say about the Apollo units and a seller contacted me VIA PM on the forum and said he hasn't really had failure on the online units but I haven't ever used them so can't vouch on their quality however to me it *looks* fairly decent.

 

[Off-The-Chart]

found out yesterday that my dad actually thought he would be able to keep stuff running with a UPS and that is why he asked me for them.

suggested to him to get a gene instead and just get small UPS to keep the stuff on so that one can switch them off until the gen is powered on.

saw a 5.5 at Makro for R5k so will see what he says.

I still plan on getting that Powercom/APC for my own pc cause I can be overly cautious when it comes to it.

 

[Gnome]

Cheap generators and switch mode power supplies don't mix well. Best get a UPS also.

 

[ponder]

Cheap generators and switch mode power supplies don't mix well. Best get a UPS also.

+1

This is really a job for someone that specialises in the field. Picking a UPS is fine but when you start going with generators etc I would get someone in that knows what they are doing.

 

[Off-The-Chart]

"switch mode power supplies"?

meant the UPS will be there so we can switch off our stuff instead of having them go with the power trip.

then we will start up the gen ourselves and can then switch stuff back on.

 

[Pada]

+1

This is really a job for someone that specialises in the field. Picking a UPS is fine but when you start going with generators etc I would get someone in that knows what they are doing.

I fully agree on you with that one!

In our office complex they installed like a massive relay switch that automatically switches between Eskom power and the generators, but they spec'd it too low. So now we experienced power failures this week due to the switch going off, but the generators didn't go on since Eskom power was fine - this all due to overloading.
Now they're replacing that switch as we speak.

Its amazing how professional engineers can stuff up a simple thing like that and cause major havoc.

 

[ponder]

"switch mode power supplies"?

meant the UPS will be there so we can switch off our stuff instead of having them go with the power trip.

then we will start up the gen ourselves and can then switch stuff back on.

No, your computers and stuff use switched-mode power supplies

He's not referring to switching things on and off

 

[Off-The-Chart]

@Gnome so you referring to having the PC connected directly to the gen, after we have switched everything off, that "does not go well together"?

and you say rather get a UPS - does that mean one can run the PC via the UPS which will be connected to the gen instead?

sorry if my questions seem newb, but that is why there are people like you

@ponder yeah didn't think he was talking about switching things on and off...

I posted that in response to him saying "rather get a UPS" where I did say in my previous post that I was going to get a UPS but merely so that we can turn the stuff off in order to have them connected to the gen.

and that is reason for my above questions cause I think he may have meant that I should rather get a UPS to "bridge" between the 2.

 

[Gnome]

@Gnome so you referring to having the PC connected directly to the gen, after we have switched everything off, that "does not go well together"?

Switch mode power supplies (SMPS) are the type of AC->DC power supplies used in PCs.

A generator, especially cheap ones (anything less than ~R30K is cheap in the generator world), have trouble keeping the frequency and voltage in check which is bad for a SMPS. The generator essentially uses an engine connected to a "alternator", the problem is as load fluctuates the generator RPM increases and decreases. That causes changes in both voltage and frequency. The same can be seen in a car, if you switch on your A/C, turn your steering with power steering or even install sound and play it loud the RPM drops and then surges upward as the engine management compensates, as load suddenly changes.

The power we get from the utility doesn't fluctuate that wildly because of the mass amount of people connected, all create a "buffer" as well as other measures taken by the utility.

A SMPS can theoretically operate with varying voltages and frequencies but it will severely strain it. Usually people run things like lawn mowers (induction motor), welders (transformer), etc. from generators. Those devices aren't damaged by the fluctuations even though their performance is impacted slightly.

and you say rather get a UPS - does that mean one can run the PC via the UPS which will be connected to the gen instead?

Yes, get a UPS and connect the UPS to the generator. The UPS uses a special type of transformer called an auto-transformer that compensates for the changes in voltage and frequency and it will also detect a brown out and protect the SMPS.

How well a UPS deals with a generator I cannot say, if it only compensates using the auto-transformer then it shouldn't damage or strain it at all.

Ideally a online UPS should be used in conjunction with a generator.

sorry if my questions seem newb, but that is why there are people like you

np. Everyone was a newb at some point

 

[Pada]

...
Yes, get a UPS and connect the UPS to the generator. The UPS uses a special type of transformer called an auto-transformer that compensates for the changes in voltage and frequency and it will also detect a brown out and protect the SMPS.

How well a UPS deals with a generator I cannot say, if it only compensates using the auto-transformer then it shouldn't damage or strain it at all.

Ideally a online UPS should be used in conjunction with a generator.


np. Everyone was a newb at some point

+1000

My guess would be that your PC would still receive varying voltage and frequencies even if you run the PC via an UPS off the generator, unless you have an online UPS which always runs the PC from the batteries.

I actually doubt that my APC Smart-UPS would filter out the fluctuations in voltage and frequency caused by the generator.
These "new" SMPS should actually be able to handle fluctuations much better than the old PSU's that simply used big transformers, but with most of the manufacturers trying to skimp on every single component, they might not monitor the frequency to let the SMPS do the necessary adjustments.

 

[Off-The-Chart]

k so running a PC would be 'risky', but how about running routers?

also Gnome, now if you were to go with the gen+UPS option for a PC, could you pls suggest a UPS that you would go for?

the gen would be as mentioned a 5.5kVA and if I were to use the calculator, I would say the PC would sit at around 300-500W.

 

[Pada]

Off-The-Chart: I would guess that the router would be more susceptible to fluctuations. You can look at the power adapter of the router for the acceptable range of frequencies and voltages.

500W for a PC is very high. My i7 940 (OC'd to ~4GHz) + 2x GTX 460 (also OC'd to ~900MHz) maxed out at 480W.
I've already said (in my first post) that the typical office PC (Core i3, 1 HDD, onboard/low end graphics card and a poor PSU) + 2 LCD screens) would use about 300W.

The only UPS' that will guarantee that your PC/router won't be damaged from fluctuations are the expensive online UPS'.

You might be able to find smart UPS' that can correct the frequencies and voltages (like with a built-in power conditioner).

One of the reasons to go for the expensive APC units is for their Equipment Protection Policy!