[Closed] Uninterruptible power supply  

Re: Uninterruptible power supply

Again, there are several factors that play into making this statement either true or false. Not all UPSs are made the same. Some are switching like this yes, but not all of them.

Aaron

Are you suggesting that an "uninterruptible power supply" is in fact interruptible? Anything that is what you seem to be suggesting cannot be labelled "uninterruptible"...

Peter

Re: Uninterruptible power supply

Again, there are several factors that play into making this statement either true or false. Not all UPSs are made the same. Some are switching like this yes, but not all of them.
Lets make terms clear.
I call UPS (Uninterruptible power source) a device, which either runs on inverter permanently (expensive ones) or switches to battery power within 20ms of power outage. All other devices I call "Backup Power Source".

This thread is about UPS.

3D priter will be happy with any type of UPS designed for protecting IT equipment.

Re: Uninterruptible power supply

Thanks Richard.I yes I did know the scale of things.
And that the UK fits inside your state with room to spare. However in the scale of things England has more tornadoes per sq mile than any other country in the world.
However we built well and when looking at you network it seems poorly built.

I worked for Texas Utilities here in the UK (TXU) after they took over the Power Distribution company I worked for. They did not last long, they pulled out and ran away after a few years, allegedly due to a bad energy trade. They did not have a clue about running a utility in another country.

https://www.theguardian.com/business/2002/nov/20/utilities

20 ms is a long time. The power supply is interrupted even for a few milliseconds. Who can afford and need to run a 3D printer on a full time battery inverted supply? And can afford the maintenance ie the need for replacement batteries and reduction in inverter efficiency over time, and when the caps blow.

Re: Uninterruptible power supply

Well, depending of the UPS type (online, offline, inline, naming may vary) you can have a switch time. 20 ms seems a realistic value. Different types of UPS have different recommended usages, depending of the capacity of powered device to hold this switch time.

However, a full online UPS is not that expensive, I still have my good old APC RS1000 for more than 10 years, and only changed the battery once, and my home server and Synology NAS have never had any problem with it during main power loss.

Regarding the printer, I'm pretty curious if the PSU of the mk2 can hold the power during the switch time of an offline UPS, and honestly, seeing his time of reaction after unplugging it, I'm convinced it can.

Re: Uninterruptible power supply

I have of course tested if the UPS that I use will continue to power the i3 MK2 when power fails. It does.

And I run the whole lot through an isolating transformer first, just because I have a few and might as well use them.

Re: Uninterruptible power supply

20 ms is a long time. The power supply is interrupted even for a few milliseconds.
Are you sure? Switching power supply of my MK2 is able to feed the printer for at least 100ms of outage, tested. It even survives when I switch it rapidly off-on by hand on mains switch during printing. Maybe I got PSU with some hell of strong capacitors? Who knows... 😉
It works with absolutely no problem with my UPS, which is NOT online, it's only line-interactive (whatever they imagine it is, it is definitely not online).

Re: Uninterruptible power supply

With a UPS just ask why you need one. Are your 3D printing needs essential for a 24 hour electricity supply? Also when you buy one, do you pay for maintenance? The caps are the first to fail with a switching UPS. As regards full inverting battery UPS the cost is high compared to the I3 Mk2 Prusa built as a kit or ready built.

20ms is a long time and lets not forget about why the mains supply failed and the transients that can get through to the printer and crash it. Mains supply faults can be dirty. The Electricity Utility suppliers do not gaurantee the waveform as totally sinusoidal and transients often exceed the RMS value of the supply. And can pass through to the printers CPU and crash it. As radiated. It happend to me many years ago following a lightning strike nearby, that got through my LV cable supply and into my telecom cable from the Secondary Substation and back from the Primary Substation via 11KV cable. The Primary Substation was fed by a dual circuit 33KV Overhead line, with a third switched via SCADA alternative. It blew my ISDN connection modem and my satellite modem. I was on a UPS at the time < job/work related. The breaker tripped at the Primary Substation.

When I say blew, they gave out the magic smoke Dave Jones talks about on his EEVBLOG Youtube channel. It cost money to replace the equipment.

The lightning strike was not direct. I know that, as I was in charge or lightining monitoring at the Power Companys I worked for over many years. We had a lightning monitoring system. As well as my real job as a Network Control Engineer.

Re: Uninterruptible power supply

I never considered UPS as a surge protection. I use it only for purpose of covering utility power outage and it works quite well. In my area there is about 1-2 power outages per month, usually lasting a few minutes. The same UPS protects all my computers and both of my 3D printers for about 6 years with no issues at all (well, MK2 only few months). I only changed UPS batteries last year since they started to be a bit weak.

Re: Uninterruptible power supply

I guess I have been very "lucky" with my UPS.

Mine was purchased in September 2010 and has been running perfectly without any maintenance ever since, except for one time in November 2013 when it stopped working and was replaced FOC (including all shipping costs). Every 6 months, I do remove all the accumulated dust (or as much as I can get to) and that is all.

It successfully protects my two servers, workstation, monitors, switch, router, modem, AP, various printers and phone system, plus 2 Prusa 3D printers. None of my equipment has ever suffered in any way whilst being protected.

And I consider a £500 outlay (including shipping from Ireland) a very small amount to pay for all that protection over (at least) 6 years. And £500 is less than the cost of one single 3D printer.

Peter.

Re: Uninterruptible power supply

Every 6 months, I do remove all the accumulated dust (or as much as I can get to) and that is all.

And, if it is not a SMF (Sealed and Maintenance Free) battery; i.e., it is a wet cell, top it off with distilled water.

Re: Uninterruptible power supply

Every 6 months, I do remove all the accumulated dust (or as much as I can get to) and that is all.

And, if it is not a SMF (Sealed and Maintenance Free) battery; i.e., it is a wet cell, top it off with distilled water.

APC are maintenance free batteries.

Peter

Re: Uninterruptible power supply

My company used to insist that we topped batteries with tap water... really irritated me. As did replacing batteries with regular monotony

Re: Uninterruptible power supply

Joan tap water and not de-inonised water? Recipe for failure if so. Yes in my day lead acid batteries. I understand todays UPS are different, however they still need monitoring and maintenance. Electrolytic caps are the main failure point with inverters still. As regards transients, they can hurt a lot from the grid.

Re: Uninterruptible power supply

If I put a solid state relay on the wires going to the heater bed and then power the heater bed with a power supply not on the UPS, would that let me get away with a much small UPS that is economical since it only powering the Rambo and the hot end?

I am only concerned when the power flickers from 1 to 3 seconds.

Also, what if I add two solid state relays and power both the hot end and bed plate from the power supply not on the UPS?

RE: Uninterruptible power supply

@joantabb

Only an idiot would suggest tap water for topping up batteries!  Distilled water is the one to use and usually not that easy to find, yes, it does cost a couple of bucks, but a far cry from replacing your batteries a lot sooner!

RE: Uninterruptible power supply

I live in Canada and use an MK3S Prusa 3d printer.  It has the power panic feature, which works, but isn't perfect.  With some frequency, there are minor power interruptions which are often just short enough to shut everything off then on again.  I was 5 and a half days into a 22 day print and this happened and when the printer resumed, there was a noticeable 1 mm layer shift.  This was probably caused by the power outage and then the printer missing a step when the print resumed.

I am looking to invest in an economical UPS to at least address short power outage issues.  Do these really work or kick in fast enough to avoid any interruption in power for the printer.  Any suggestions of what I would buy?

RE: Uninterruptible power supply

The MK3s is designed to detect very short outages (glitches) to safe it's state during print and (try to) resume afterwards. Therefore, any switch that switchs from a straight-thru mains to printer to the battery, would trigger this safe/resume feature.

Therefore you should buy a (more expensive) "online" UPS, which has no switch but powers the printer permanently from a DC bus which means that you can think of running permanently from batteries being charged as long as mains is there.

What I will be trying next, is
  1. removing the power-failure-wire from the PSU to the  Einsy
  2. using a 24V battery to directly (via fuse and power switch) power the Einsy power input.
  3. Charging is done either (depending on the exact voltages) from the prusa PSU or a special charger as long as there is mains supply.

just my 2 cents.

RE: Uninterruptible power supply

Today we had a power outage that lasted about 10 seconds, briefly restored and immediately failed again for a further ten or so, seconds... 

Of course, my Mk3S with MMU2 was printing at the time... 

I now have to reset my clocks in various equipment, and alarm clocks... etc. 

My laptop ignored the inconvenience, as did My UPS, and the Mk3 Carried on regardless...    (My Power panic line is still connected...) 

this saved the print, where as if I had not had the UPS, the print would probably have been trashed, power panic has never recovered from a double hit power outage, for me!

Glad I wasn't using my old Laptop, it has no battery...  

Joan

RE: Uninterruptible power supply

@joantabb

The uninterruptible power supplies work pretty good.  About a week ago, there was a power outage that lasted about 8 minutes.  Both of my mk3s printers and my computer were running at that time..all connected to the UPS.  Everything else in the house went offline, including my wife's two workstations she uses for her job, but my UPS saved the day as neither the computer or printers were interrupted at all.  Had the power outage lasted 15 minutes longer, that probably wouldn't have been the case.  Basically, the more you pay for them, the longer battery life you get as well as allowable wattage for having equipment connected to them.  Mine is a 1500 AVR and was a good choice for about $200 Canadian.