Power Supply Upgrades
Yesterday before I got started on a long 30+ hr print, I hooked up the unit to my P3 International Power strip in the link below. Printing with PETG with an exruder temp of 240 C and a bed temp of 90 C I average around 160 watts with minimum of 105 and a max power of 225 watts. What interested me the most on the power strip was the low PF (power factor) that I was getting. I averaged 50% with a minimum of 45% and a max of 55%. This is pretty low and I know part of it has to do with the numerous motors on the unit which aren't in their efficient range. I wonder how much a better/higher quality PSU would increase the PF %. Being that I have a bunch of PSU's that are gold rated and are anywhere from 850-1250w rated, I'd like to see how much more efficient this would be. Even though theses PSU's won't be operating in their sweet spot (50% Load or so), I think a good quality PSU might save you 20% on your watts. If you plan to print year long this can amount to a decent chunk of change. Before I do this, I'd figure I'd see if anyone here has done any tests on this. If I go through with this I'll just plan to cut the PSU power wires under the print bed and either use XT60 connectors or anderson power pole connectors which I have a bunch of from my RC stuff. I'll make a female PCI-express adapters to whatever connector I decide on.
Math Part
If the unit pulls on average 160 watts an hour *24 hours this gives you 3840 watts a day or 3.84 kWh. In the states most peoples energy falls in between $0.10-$0.30 a kWh. Lets assume $0.20 a kWh then you'd use $0.77 a day. In a year you'd use $281.05. Now if you save 20% in power your bill would only be $224.84 and you'd save $56.21 yearly.
Power Meter
http://www.p3international.com/products/p4330.html
Re: Power Supply Upgrades
Jeff
That's interesting. I doubt the motors would have such a huge effect on the power factor. My guess would be that the heated bed - the largest current draw - is probably very inductive, and being driven by a PWM supply is a major reason for the power factor issue.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Power Supply Upgrades
> That's interesting. I doubt the motors would have such a huge effect on the power factor. My guess would be that the heated bed - the largest current draw - is probably very inductive, and being driven by a PWM supply is a major reason for the power factor issue.
The bed may be inductive, but the PWM is so slow that it hardly matters.
Re: Power Supply Upgrades
I think the power factor depends on quality and efficiency of used switching power supply, am I right?
Re: Power Supply Upgrades
The bed may be inductive, but the PWM is so slow that it hardly matters.
Rise and fall times in the region of 60ns (not particularly slow). I would think that, coupled with square wave output may cause some inductive characteristics.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Power Supply Upgrades
I was going to work on the project today until my solder iron on my hot air rework station didn't work. I have a replacement solder iron coming in this week so I'll update later this week once it comes in and I can get to work.
Re: Power Supply Upgrades
Power factor is purely imaginary ignore it. I induce the people to do this with the Genuine Prusa I3 MK2. Too small to worry if you can afford the filament for this wonderful hobby. Otherwise try to reduce your worry in a switchmode power supply after it passes into the DC. Like all modern day AC to DC electronics ie HD LCD , OLED and 4K TV's Which most people use most, their TV and by family if your have one, if not the worry about Power Factor can make you Billy no mates 🙂
Nigel
Life is keeping interested and excited by knowledge and new things.
Re: Power Supply Upgrades
Too small to worry if you can afford the filament for this wonderful hobby.
These words should be carved in marble. 😎