3D printer power factor/efficiency

[meilon]

Hello there!

 

I couldn't find anything on the interwebs discussing this, so I hope I find some other people in these here forum to provide some answers:

 

What is the efficiency of your 3D printer at which mains voltage and frequency for your prints?

 

For this purpose I made a Google Form: [deleted because not relevant]

The answers will be collected here: [deleted because not relevant]

 

I'm tracking my Bambu Labs X1CC with a Tasmota enabled plug in Home Assistant and found out that while the general print is running, the power factor is reported at just below 0.5 on average. I find that way to low! I already opened a case with Bambu Labs and am waiting on a replay, but I'd like to know if this is absolutely normal. If you have a 3D printer and a way to measure the power efficiency at the power plug I would be happy if you would fill out the form or provide an answer in this thread. Sadly, most smart plugs don't. I attached a graph of a full print with PLA on the heat bed enabled PEI plate. 

 

Are your printers about the same? Is this normal?

 

Edited August 4, 2023 by meilon
Removed links to Google Docs because not needed and I deleted them

[Senzelian]

How exactly does this meter measure power efficiency?

[Electronics Wizardy]

Generally for residential settings, power factor doesn't matter for you. It isn't a measure of efficiency of a device either. You pay for Watts, not VA normally, so your device can use as much VA as you want and it won't affect your power bill. 

 

The PSU probalby don't have apfc. If its a low power device thats normal, but how much power is this pulling?

[meilon]

Thank you both for your reply. I can see that the Tasmota enabled smart plug seems to use a CSE7766 as per its config, I don't know what chip is used in the other one because its BLE only.

 

While its true I'm only paying for the active power, from an environmental standpoint I think most devices should be as efficient as they can be. The energy has to come from somewhere, doesn't it?

 

Most of the time my meters measured about 110W after the first layer, with a few spikes to 200W. But when that happened the power factor went up as well, so the apparent power is pretty constant at 240 to 260 VA

[Kilrah]

19 minutes ago, meilon said:

The energy has to come from somewhere, doesn't it?

Reactive power is not consumed power, the energy temporarily gets to the device before flying straight back out to the grid, hence the "not being a measure of efficiency".

Yes the higher current causes a little extra transmission loss which is why high power devices and installations use means to reduce it, but it's negligible for a 100W device so just about anything in this range won't care.

[meilon]

So why do we strive for 80+ Titanium and even the base tier Cybernetics Bronze requires a PF of above 0.91 @ 230V (forget that, thats at 100% load) if it doesn't matter? Only because they could consume upwards of 500W?

[Kilrah]

1 hour ago, meilon said:

80+ Titanium

That's about efficiency, again PF has nothing to do with efficiency.

PC power supplies have pretty strict regulatory requirements about not causing harmonic distorsion on the mains supply, and active PFC is how you keep that in check. Above a certain power they pretty much can't satisfy the requirements without it.

[ImorallySourcedElectrons]

On 7/18/2023 at 8:55 PM, Kilrah said:

Reactive power is not consumed power, the energy temporarily gets to the device before flying straight back out to the grid, hence the "not being a measure of efficiency".

Yes the higher current causes a little extra transmission loss which is why high power devices and installations use means to reduce it, but it's negligible for a 100W device so just about anything in this range won't care.

Sort of, except if it's in a specific category (and I don't think 3D printers are), anything above 75W has to include some degree of PFC if it has EC labelling.

[meilon]

You are right, as far as I could research there are rules for devices between 75W and 600W, contained in the standard IEC 61000-3-2, which got adopted by the EU as EN 61000-3-2, which is required for CE certification, which the X1 Carbon apparently conforms to: https://public-cdn.bambulab.com/portal/euro-compliance/X1-Carbon_2305311613.pdf

 

The problem is: The standard is actually for "Limits for harmonic current emissions", which is, from what I understand, what the power factor describes or at least relates to. And because standard costs money and are in this case to technically for me anyways, I have no idea if my X1 Carbon complies with this standard.

[ImorallySourcedElectrons]

On 7/24/2023 at 5:21 PM, meilon said:

You are right, as far as I could research there are rules for devices between 75W and 600W, contained in the standard IEC 61000-3-2, which got adopted by the EU as EN 61000-3-2, which is required for CE certification, which the X1 Carbon apparently conforms to: https://public-cdn.bambulab.com/portal/euro-compliance/X1-Carbon_2305311613.pdf

 

The problem is: The standard is actually for "Limits for harmonic current emissions", which is, from what I understand, what the power factor describes or at least relates to. And because standard costs money and are in this case to technically for me anyways, I have no idea if my X1 Carbon complies with this standard.

No one sane designs their own PSU, most 3D printers include a black box PSU that's been separately certified, though some of them simply use a known-good reference design.

[MG2R]

Don’t worry about it. The only one caring about PFC are the utility companies as they lose out on money if your power factor is too low. Hence, you only have a problem if your avg power factor of the entire house drops below a certain number (e.g. 90) as the utility will add a surcharge. 
 

As said by others, power factor is NOT efficiency. Power factor describes the relation between voltage and current phases in an AC system. Efficiency is a measure of useful work that is done for every amount of energy consumed.

 

Adding power factor correction to a circuit actually makes it ever so slightly less efficient as you’re essentially adding a big capacitor or inductor. While in theory that only changes the PF, in practice every electrical component has a certain amount of resistive losses.

[ImorallySourcedElectrons]

On 8/1/2023 at 9:12 AM, MG2R said:

Don’t worry about it. The only one caring about PFC are the utility companies as they lose out on money if your power factor is too low. Hence, you only have a problem if your avg power factor of the entire house drops below a certain number (e.g. 90) as the utility will add a surcharge. 
 

As said by others, power factor is NOT efficiency. Power factor describes the relation between voltage and current phases in an AC system. Efficiency is a measure of useful work that is done for every amount of energy consumed.

 

Adding power factor correction to a circuit actually makes it ever so slightly less efficient as you’re essentially adding a big capacitor or inductor. While in theory that only changes the PF, in practice every electrical component has a certain amount of resistive losses.

I must say this is a really bad take on the subject, you're not considering grid losses in this assessment, and those very much get billed to you as well. Always try to aim for a good power factor, if no one is a douchebag we all pay less overall.

[MG2R]

24 minutes ago, ImorallySourcedElectrons said:

I must say this is a really bad take on the subject, 

It’s an accurate take. 
 

PF is monitored by the utilities because otherwise people would be douches and install large capacitor or coil banks to lower their power factor to near zero. If yours is too low the utility company will see to it that you know. 

OP is worrying about a single device with a bad power factor in their house. The device is relatively low

power and does not run nearly 24/7. Overall impact will be really low. 
 

as long as the house PF stays within the limit set by the law… why worry? 

[ImorallySourcedElectrons]

1 minute ago, MG2R said:

It’s an accurate take. 
 

PF is monitored by the utilities because otherwise people would be douches and install large capacitor or coil banks to lower their power factor to near zero. If yours is too low the utility company will see to it that you know. 

OP is worrying about a single device with a bad power factor in their house. The device is relatively low

power and does not run nearly 24/7. Overall impact will be really low. 
 

as long as the house PF stays within the limit set by the law… why worry? 

Yes and no, one device with a bad PFC won't make a huge difference, but this is a death by a thousand cuts scenario from the grid operator's point of view. You see it as one device, but now imagine each household has a couple of those, it quickly adds up and does reduce the overall infrastructure efficiency by quite a bit. Adding PFC is a relatively cheap thing to do as designer, and even the little efforts do add up when you're talking about millions of households. This is literally why the EU pretty much made PFC mandatory. So while I wouldn't worry about it in the case of a single printer that only sees occasional use, I've seen plenty of folks advice someone intentionally ruins the power factor of their entire house to try and dodge the meter based on the same mindset.

[MG2R]

Oh hey, I’m all for mandated PFC in manufactured goods. 
 

OP was worrying about their device. I said they should not worry about it and gave an explanation why for their specific scenario I wouldn’t do anything to change it. 
 

That’s the only thing I said here. If OP was a manufacturer asking whether or not they should be adding PFC to this 3D printer before putting it to market, that’s an entirely different story. 

[ImorallySourcedElectrons]

On 8/7/2023 at 11:16 PM, MG2R said:

Oh hey, I’m all for mandated PFC in manufactured goods. 
 

OP was worrying about their device. I said they should not worry about it and gave an explanation why for their specific scenario I wouldn’t do anything to change it. 
 

That’s the only thing I said here. If OP was a manufacturer asking whether or not they should be adding PFC to this 3D printer before putting it to market, that’s an entirely different story. 

Yeah, for one device it's not an issue. The real issue at this point is that a lot of companies import crappy power bricks with fake certification and then flood the market with really cheap ones, pushing the good suppliers that do put in the time out of the market very quickly