We need a UPS! What are you using?

Hi All!

Does the form 2 handle cheap UPS’s well or should I get a better quality one?

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We have had a power outage for the 3rd time during a print now and this time was right when we really didn’t need anything to delay our prints!

We have finally decided to get ourselves a UPS for the work horse (the 3D printer) but I’m not sure what one to get. Basically, there’s two types of UPS’s on the market; Pure sine wave, and simulated sine wave. You may know them under different names so here’s a super quick breakdown.

Pure Sine Wave UPS: generates a pure sine wave (exactly like mains power)
Simulated Sine Wave UPS: generates a square wave that mimics a sine wave.

A simulated sine wave UPS are much cheaper than a pure sine wave UPS. They’re considered to be the “consumer grade” type product, the pure sine wave UPS being the “business grade” type product.

My question is, does anyone have a simulated sine wave UPS and how does the printer handle it? I’m not sure how sensitive the printer is to an unstable power source, and being a simulated wave its much less efficient than your typical mains power.

Any input is greatly appreciated!

I don’t know English, through a translator. I use a simple UPS for formlabs 2. I have a 20-watt laser for engraving. The FSP Knight PRO UPS is there, it makes a lot of noise but is cheap with a double conversion. On lasers, it is impossible that the voltage disappears, the laser spoils from overheating

FSP Knight PRO UPS Loud noise

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Not just pure sine wave, but I’ve got a dual conversion/online UPS rather than a line-interactive one; Eaton 9PX1000iRT2U.

Reports a bit under 2 hours runtime while my Form 3 is printing. The printer uses a bit more power for the first 20 minutes or so while it’s heating up (80-100W) but settles down (to 50-60W) for the rest of the print job. Might have to revisit those numbers come winter when it has to run the heater more.

I feel like the printer is going to have a switchmode PSU which should tolerate all kinds of crappy power (you can often feed DC into them and have it work just fine), but I wasn’t about to push it.

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APC is a PS manufacturer, and they have a UPS selector/calculator on their website. Here is link to the caculator.

Right now it’s configured for 70W load, you can change that number to whatever you want. You can also put in how much runtime you want to get out of it, and it will sow you the UPS that meet that requirement. right now it’s setup for 70W load and no minimum runtime, so it will show you everything available


FYI, I have a Backps-Pro BX1000M, and I have a fairly power hungry PC connected to it, a 24" monitor, and a 24port DLink managed switch, and I get about 30~40 minutes of running my PC.

If I put my PC in sleep mode, and the monitor goes to sleep as well, then only the switch is up, but it draws <20W, it lasts for about 3 hours.

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Thanks for the responses! :slightly_smiling_face:

@qupada your UPS is probably the best of the best type which I’d love to get but will probably be way outside the budget. I doubt I’ll be able to justify getting something like that for just the 3D printer :stuck_out_tongue_winking_eye:
We are putting a server into the same room as the 3D printer this year so maybe once thats in I’ll be able to justify this :joy:

@Dudemeister your UPS is a simualated sine wave type UPS, have you ever noticed anything odd when using the UPS? Say during a power cut and you’ve switched to the UPS, does the printer still run fine with no issues?

First, let me say that I don’t have my printer on a UPS, although I should, but to me, having the computer on a UPS is more important. If a print fails, due to a power loss, then no big thing, I just start over. Most of my prints nowadays are less than 8 hour prints and don’t consume that much resin.

Never the less, I’ve never noticed any problems with my UPS or my computer. In the last 2 years, I’ve only had 2, maybe 3 power outages, and in both cases, the the UPS did it’s job. The most recent outage was nearly 8 hours long, and the UPS software, put the computer in hibernation when the UPS battery was down to 10%.

If the PC is functioning OK, I don’t see why the printer wouldn’t work just as well.

FWIW, my understanding of a “pure” sine wave vs a simulated" sine wave, is the quality of the AC output. and while that may have an effect on certain devices like AC motors, or high-end/high-output amplifiers, today’s power supplies that are either integrated into computing devices or power bricks for many of today’s electronics, have all kinds of filters and electronics inside that deal wth dirty AC and ultimately output a steady DC power that these devices need.

In short, I don’t think a device like the Form printer would care, because it’s internal switching PSU takes care of all that dirty AC anyway.

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I totally agree. Nowadays the switch mode power supplies are capable of handling crappy AC inputs, it just effects its efficiency, usually generates more heat too.

Thanks for you input! :slightly_smiling_face:
I think we’ll probably end up opting for the simulated sine wave UPS as its much cheaper.

We’ll get a better one once the server is up and running, which won’t be for a while.

Yeah it definitely ain’t cheap, but I figured after spending what I did on the Form3+Wash+Cure+consumables, it didn’t seem like such a big sum of money any more.

Plus I got a network card for it for free (supplier was running a promotion), those are usually a few hundred bucks by themselves which took some of the sting out of the pricetag.

I bought an APC BE550G for our Form. The wash and cure and a couple other things are plugged into the non-backed-up sockets and the form itself into the battery backed up one. Everything has worked just fine, although the UPS has not yet been called upon in anger.

To amplify on the power quality comments… I know a bit about power supplies. In a typical flyback AC-DC system, step 1 is to rectify the incoming AC to make HV DC anyway, which is why none of them care about the incoming line frequency and typically have very, very wide input voltage ranges.