What KVA UPS

[jay vyas]

hey hieee,

i wanted a suggestion from you people what KVA online ups (uninterrupted power supply) should i get for my epilog mini 35watts and one computer...:)

waiting for a positive reply...:)

[Scott Shepherd]

Jay, you should check with Epilog on using a UPS. There is a discussion about what a UPS does to the power (changes the wave shape) and it's probably something you should verify with Epilog prior to using one just in case there is an issue.

I wouldn't want you to use one for a year, have something happen and then you get told "oh, well, we won't cover that because you had a UPS in place".

Not saying that's the case at all, it might be perfectly fine, but it's an answer that should come from the factory in my opinion, to protect yourself.

[Rodne Gold]

1-1.5 kva will do. - we use a 2.5 kva machine for 2 30w Lasers.
Get one that takes AC power , converts it to DC and smoothes everything and then converts DC to "perfect" AC.
Kva really means nothing , considering these units use batteries , you need to know power over time , IE will it allow an hour of running time for your machines. so you need to know what the Wattage it will deliver in lets say an hour. The better UPs's have tons of batteries and will run your stuff for a long time but are expensive. You must also look at the quality of the batteries used , cheap ones fail soon and cost a ton to replace. The batteries used must also be correct in terms of their cycle rating.
I cant see why you would have an issue with warrantees and a UPS
The UPS can also solve problems like banding etc , and it isolates the laser etc when you get power brownouts or dips from the elec utility or other machines being switched on the circuit.
I would use "clean" lines for the laser and puter and dump the UPS on em. IE get an electrician to install a line with nothing else on , its own earth etc - ask hiom for a clean line...wont cost the earth and it will certainly help.
We have a lot of power failures and use the UPS's but we have backup generators - 5 Honda 6.5kw machines which run the rest of my machinery and outfit...Unfotunately a UPS sufficienty to keep all this operatin for a brief period is ubnerexpensive, so we sometimes lose jobs.
We worked out that we lose $80 per machine per hr its not operating
10+ machines noty operatin ios like $700 per day loss at LEAST , in reality prolly 2x that.
Point im making is these gennys have Voltage and current regulators and seem as good to feed power as anything else....
So a better srategy for you is to choose a UPS than can keep you going 15 mins , and get a 4-6kva genny that autokicks in when power goes down
So in essence you have a UPS , and if the power problems persist , a genny that can run just about anything you got. Genny will keep you going about 6-7 hrs at 6kw with 25 litres of gas.
I dunno a ups price , but a good honda genny at 6.5kw is round a grand
I cant see a system setting you back more than 2k
You must work out whether you need all this tho...maybe just a smoothing device is ok?

[jay vyas]

@Rodne Gold

i have a 1kva online ups and it has worked fine for me from last 6-7 months with 1 computer and 1 35watts laser machine on it but suddenly 1week ago my motherboard burntout and company gave me another replacement that new motherboard worked well for 1 week and again that also burntout now the company's agent here in india says that there is a prob with the ups i called the ups technician and checked the input and output of ups which was fine and the earthing was also fine but still the agent says you need to get a new ups replaced and when i asked some ups technician they told me you will have to get 3kva ups for 35watts machine and 1 computer

now please suggest me what to do???

[John Noell]

Epilog told me that the current draw on a Mini 18 45W is 880 watts. A somewhat typical watt to kva conversion (which depends directly on the variable "power factor") would give about 1.1 to 1.4 KVA. A typical computer has a 400 watt (at max output) power supply which may draw in the range of 600 watts max. Add in a screen for the computer and a conservative approach says you may need something as high as 3KVA but you can almost certainly get by with less. I have seen UPSs that put out some nasty high voltages (up to 330V instad of 230V) when under full load and caused problems but that is rare. However, I've never seen it in name brand UPSs like APC.

[Darren Null]

Can you make a homebrew UPS?:

Car battery charger
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V
The thingy to stop you overcharging the battery (forget what it's called- I have one built into my charger)
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V
Bank of serious KWh boat/caravan batteries
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V
Inverter (Good quality)
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|
V
Electrical toys

In theory, if the charger and inverter are up for the job, you could add batteries at need/convenience. Am I talking out of my hat? Once you get over a domestic-ish load, UPS systems seem stupidly expensive to me. Also, being able to throw another battery in, if one fries, without having to replace the whole kit makes more sense to me.

[Scott Shepherd]

Darren, you have WAYYYYYY too much time on your hands :) You can buy those things already made for $75 with a warranty that replaces the battery :)

I know 'cause APC just sent me an entire new unit with a new battery in it as well, due to the fact the original wouldn't hold a charge.

There's a calculator here : http://www.apc.com/tools/ups_selector/index.cfm

You'll probably use the "Configure by load" button.

[jay vyas]

@Scott Shepherd

i calculated on the link given by you but that site says not to attach a laser printer on the ups and they showed 1kva ups please help me out with or without laser printer and theres no option for laser cutting/engraving machine...???

[Scott Shepherd]

Sorry Jay, I couldn't tell you that. My knowledge about electricity is this- you flip the switch and the light comes on. Flip it the other way, the light goes off.

[Darren Null]

Darren, you have WAYYYYYY too much time on your hands
I'm toying with the idea of leaving the electrical grid altogether when I move house next. The setup above is most of the way to a solar installation. It'll depend on getting the batteries and panels cheaply enough. I'm in the right place to go solar.

The $75 ones are a little lacking in power for me.

[John Noell]

Jay, we have flaky power here and Epilog did not seem to see any need for a UPS when I asked about it. They had some trouble with my question and clearly do not expect a UPS to be used. The APC warning about laser printers on a UPS that is protecting your computer is because those printers can draw a lot of power (for heating the fuser) - enough to overload the UPS. I suspect we only need surge protection to safeguard our lasers and a UPS only if we want to avoid losing jobs in progress. (And that would mean a pretty big UPS with a lot of battery power. Some APC UPSs can have added external batteries for longer run time.)

[jay vyas]

@John Noell

but here co. agents are saying to get ups compulsory

help me am planning to go for 3kva ups with isolation tranformer help taking decision...

more suggestions welcome please

[Kim Vellore]

I am not sure why you need a UPS, a voltage stabilizer and a surge protector would make sense. Anyway, the laser uses a 48V power supplying it and even if it supplies 20A at 48V your power will be <1100W considering reasonable efficiency. That is 1.1KVA, now you will be expected to run the blower, PC and the compressor with the same UPS, else you could be lasering without exhaust which may be used for the laser tube cooling. Just add their KVA to this number and you will get a KVA number to look for your UPS.

Now how long do you expect to run the laser on the UPS, if you need it for a couple of hours, you will land up with a lot of big batteries and chargers that go with it.

Isolation transformer? why do you need this for. Maybe you should ask your 'Co Agents' for their reasoning for all this and if it makes sense ask them to recommend you one.

Kim

[jay vyas]

@Kim Vellore

i need a UPS so that due to sudden power failure my machine should not get a spike so UPS does the protection secondly i don't want to connect blower pump etc. only 1 laser machine and 1 comp with lcd moniter.

voltage stabilizer and surge protector will only avoid fluctuation and will not avoid my machine from sudden light failure...

please more suggestions welcome help am from india suggest accordingly:)

[Darren Null]

3KV will protect your machine and will give you time to save your work and turn the computer off gracefully. If you want to save the material/job you're working on too, I would strongly consider adding a generator that will supply sufficient power for a few hours. You can get ones that kick in automatically; although if you do get a power outage your UPS will be beeping madly and will give you plenty of time to fire up the genny; assuming you're not running the machine unattended.

My personal experience has led me to the conclusion that surge protectors are a complete waste of time, but I haven't used one in tandem with a voltage regulator.

[John Noell]

Epilog said my 45W laser uses 880 Watts. I doubt that the power factor is 1.0 so I would bet KVA is more like 35% higher, maybe ~1200VA. But the MOST IMPORTANT QUESTION is what are you protecting against? Surges, brownouts, off frequency, or maybe complete power loss but need to keep working? Each calls for a different stategy. (Many UPS have very poor over-voltage protection - except extreme surge blocking - but provide power in case of mains failure.)

[jay vyas]

@John Noell

basically i want my protect my machine from high pulse or fluctuating power supply and i just want a back-up of 10mins just to shutdown my machine properly as i have mentioned 1 of my original motherboard has burnt and i got a replacement from the company dealer and that new motherboard also burnt out within 1 week and i bared a loss of indian Rs. 52,000 for paying custom:(

[Kim Vellore]

Jay,
Now I understand your paranoia. Here is a thought, if Epilog is using the same power supply as in the models here it is rated for ~90-260VAC and if you are running it at 220V then there is a small margin for over voltage. I would suggest instead of Isolation transformer use it as a 220-110V transformer and use it in 110VAC. This coupled with a good surge protector might be more economical.

Technically this laser board should be as robust as any PC connected to the same power line, if you don't have PC's blowing up then this Motherboard should also not be blowing up.

With a UPS (Edit) you are again limited to the robustness of the converter. If the converter supplies over voltage at any time you might land up with the same situation.


Kim

[Steven Hardy]

I am not sure why you need a UPS, a voltage stabilizer and a surge protector would make sense. Anyway, the laser uses a 48V power supplying it and even if it supplies 20A at 48V your power will be <1100W considering reasonable efficiency. That is 1.1KVA, now you will be expected to run the blower, PC and the compressor with the same UPS, else you could be lasering without exhaust which may be used for the laser tube cooling. Just add their KVA to this number and you will get a KVA number to look for your UPS.

Now how long do you expect to run the laser on the UPS, if you need it for a couple of hours, you will land up with a lot of big batteries and chargers that go with it.

Isolation transformer? why do you need this for. Maybe you should ask your 'Co Agents' for their reasoning for all this and if it makes sense ask them to recommend you one.

Kim
(1) a proper sized and rated UpS from apic can do a proper shutdown of your system for you.
(2) To loose power on most modern electronics is not nearly as bad as having one go off-on-off-on-off0on etc..in the event of an thunder storm.

[jay vyas]

thanks for your replys i have a 1KVA UPS and 99% i guess its fine and the problem occured wasn't due to that i would like to ask you people and would like you people to suggest me

on my epilog mini 18x12 35watts motherboard there is a U31 IC EFEB 8919 (3430) this chip has burnt can you people please let me know what would be the reason for this chip to burn and person who had technical knowledge about this motherboard can help out.:)

(please can anyone provide me the diagram of the motherboard of epilog mini 18x12 35watts)