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Phil
 Phil
(@phil-4)
Trusted Member
Power Supply Issue?

So, I know people have had power supply issues, but this is different. My supply seems to work fine and print fine, but I just started experiencing a weird issue and i'm not sure if its a problem or not.

Short version: When my bed is heating, my kitchen lights flicker. I just recently replaced my kitchen ceiling fan lights with new higher wattage LED bulbs. Now, when the print bed is actively heating, the kitchen lights flicker. I'm not sure if the new bulbs are just really sensitive to line noise, if my power supply is starting to go, or what. I will also say that it is winter here in Chicago, so we get little to no outside sunlight. I have a suspicion that maybe this has always been a problem but that we are just noticing it because the overhead lights are now our only source of illumination.

Any thoughts? Should I be concerned, or is this just a thing that happens? Let me tell you it took quite the troubleshooting process to connect my kitchen lights to the printer bed in my home office heating, but after several tests it is definitely accurate. If I am printing and go to the bed and lower the temp, the light are perfectly steady until the bed temperature drops to the point that it needs to engage the heater again.

Posted : 04/01/2019 1:22 am
Patrick McNamara
(@patrick-mcnamara)
Estimable Member
Re: Power Supply Issue?

See my post here: https://shop.prusa3d.com/forum/hardware-firmware-and-software-help-f64/power-supply-failure-t13443-s550.html#p110592

Others have seen this. My lights only flicker when dimmed -- not when running at 100% brightness. I noticed it because the default on setting is 50% brightness. I also see flickering in my lights when running my heat gun, which has a digitally controller variable output. For me, it seems to have as much to do with the dimmer as it does the lights.

Curious if your kitchen lights are on a dimmer as well.

Posted : 04/01/2019 6:42 pm
Phil
 Phil
(@phil-4)
Trusted Member
Topic starter answered:
Re: Power Supply Issue?

No dimmer involved. I took some time to read through your analysis on the other thread. Seems like this is an "annoyance" issue, but not something that needs immediate intervention unless the PSU actually dies.

Would you agree?

Posted : 04/01/2019 7:47 pm
Dewey79
(@dewey79)
Honorable Member
Re: Power Supply Issue?

With the power supply problems I read about before getting my printer I purchased a UPS. I've never had issues with power supplies and I even purchased a MeanWell as a standby just to be safe.

Posted : 04/01/2019 8:50 pm
Patrick McNamara
(@patrick-mcnamara)
Estimable Member
Re: Power Supply Issue?


No dimmer involved. I took some time to read through your analysis on the other thread. Seems like this is an "annoyance" issue, but not something that needs immediate intervention unless the PSU actually dies.

Would you agree?

Yes, I consider it an annoyance issue.

Posted : 04/01/2019 9:25 pm
lawrence.g2
(@lawrence-g2)
Active Member
Re: Power Supply Issue?

You appear to have the printer on the same household circuit {breaker} as your lights. Significantly increasing the load on a household circuit will cause the voltage to drop slightly. Significantly decreasing the load on a household circuit will cause the voltage to go back up to nominal. It doesn't matter if the load is a 3D printer, hair dryer, vacuum cleaner, toaster, or laser printer.

This effect is invisible/masked with incandescent and florescent lamps, albeit for different reasons. LED lamps do not mask the effect of voltage droop.

When you use a vacuum cleaner or other high current device on the same circuit as your LED lights, the LEDs will dim once when you turn it on, and brighten once when you turn it off. Our 3D printers use rapid pulses, perhaps several per second, to the high-current heating elements. As the load presented to the main circuit is changing rapidly, you will see the lights flicker at the same rate.

Builders/electricians put in dedicated circuits for high current devices like refrigerators, and most modern kitchens have more than one circuit. Depending on how your kitchen is wired, you may have a different circuit available that won't cause the lights to flicker with the rapidly changing load of the 3D printer.

Posted : 05/01/2019 9:13 pm
Patrick McNamara
(@patrick-mcnamara)
Estimable Member
Re: Power Supply Issue?


You appear to have the printer on the same household circuit {breaker} as your lights. Significantly increasing the load on a household circuit will cause the voltage to drop slightly. Significantly decreasing the load on a household circuit will cause the voltage to go back up to nominal. It doesn't matter if the load is a 3D printer, hair dryer, vacuum cleaner, toaster, or laser printer.

This effect is invisible/masked with incandescent and florescent lamps, albeit for different reasons. LED lamps do not mask the effect of voltage droop.

When you use a vacuum cleaner or other high current device on the same circuit as your LED lights, the LEDs will dim once when you turn it on, and brighten once when you turn it off. Our 3D printers use rapid pulses, perhaps several per second, to the high-current heating elements. As the load presented to the main circuit is changing rapidly, you will see the lights flicker at the same rate.

Builders/electricians put in dedicated circuits for high current devices like refrigerators, and most modern kitchens have more than one circuit. Depending on how your kitchen is wired, you may have a different circuit available that won't cause the lights to flicker with the rapidly changing load of the 3D printer.

Sorry to disagree on all points.

While significantly overloading a circuit can cause a voltage drop. A 20A circuit on #14 copper could drop 10V at full load, at the very end of the circuit. This assume 100 ft of wire from the breaker box to the end of the circuit where the load is. There isn't much that will be impacted by 110V rather than 120V at the wall. Certainly not an LED light. Very few LED lights are directly fed by the wall voltage, and none that are dimmable. Most LED bulbs have a driver circuit that is effectively a buck converter. So long as the input voltage is within the input range of the converter, the system will work as expected. The lower input range is usually 80V.

If you look at the scope waveforms in my linked post, you will note that the AC voltage level is constant, regardless of the load of the printer, both during initial heating and PWM temperature maintenance.

Now, all that said, it is obviously an interaction between the printer load and the LED drivers that is causing what we perceive as a flicker, so your recommendation to try a different plug is definitely valid.

--SS

Posted : 06/01/2019 4:13 am
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