Mains bed pwm frequency/flickering lights.

[T3P3Tony]

Might be worth setting them to bang bang mode in that case...

[droftarts]

@hackinistrator said in Mains bed pwm frequency/flickering lights.:

I'm not sure whats the minimum pwm freq , you can try Q value of 0.1 or lower

I did a quick test, as I'd suggested Q0.1 in a previous thread, but minimum PWM appears to be 1Hz:

M950 H0
Heater 0 pin bedheat frequency 250Hz, sensor 0
M950 H0 Q1
M950 H0
Heater 0 pin bedheat frequency 1Hz, sensor 0
M950 H0 Q0.1
M950 H0
Heater 0 pin bedheat frequency 1Hz, sensor 0
M950 H0 Q0
M950 H0
Heater 0 pin bedheat frequency 1Hz, sensor 0
M950 H0 Q10
M950 H0
Heater 0 pin bedheat frequency 10Hz, sensor 0

Ian

[mendenmh]

@Surgikill I should note that, in reply to people who think an 800 watt bed won't flicker your lights, the 200 watt bed on my printer was plenty.

Note that LED lighting is very sensitive to voltage, and I had somehow allowed the PWM to fall back to 10 Hz at some point. A 10 Hz modulation of light seems to be right at the very peak of my eye's sensitivity. It wasn't visible on incandescent lights or CFLs. It may be a consequence of my buying largely very cheap LED lights from Home Depot, too. My better-grade bulbs didn't flicker visibly.

I doubt my line voltage was changing by more than a fraction of a percent but it was terribly annoying. Moving the PWM back to 60 Hz fixed it. It had two effects: first, most of the modulated energy was then being provided by the filter capacitors on the power supply, so very little of the fluctuation was being sourced by the power lines; second, my eye isn't very sensitive to 60 Hz modulation in the first place.

FWIW

[fcwilt]

You've got a house wiring problem.

I see two solutions short of trying to get by with a DC powered bed heater.

• run another line from the load center to a dedicated outlet for your printer
• get a suitably rated dual-conversion UPS to power your printer

Frederick

[tenaja]

Don't forget ohms law...a couple guys have alluded to it, but you need to embrace it.

[jens55]

@fcwilt said in Mains bed pwm frequency/flickering lights.:

You've got a house wiring problem.

I see two solutions short of trying to get by with a DC powered bed heater.

• run another line from the load center to a dedicated outlet for your printer
• get a suitably rated dual-conversion UPS to power your printer

Frederick

Those are the two choices that make sense. Note the "dual-conversion" bit. A regular UPS is not likely to fix anything and if in fact it reacts to the brown outs, it will likely kill the UPS in no time flat (of course depending on the quality of the UPS)

[Surgikill]

@tenaja Ohm's law is what is killing me. That, and the idiots that wired this house.

[jens55]

While this may sound stupid, if you want to go cheap and cheerful, get a 12 ga extension cord (HD outdoor type used by contractors) and run it from the FIRST outlet on that circuit directly to the printer.
Might want to try the printer directly on that FIRST outlet to see if it makes sense buying a long extension cord.
That way you will bypass all the joints that are made with wiring nuts for each and every outlet that is wired in a long string.

[Surgikill]

@jens55 I can try that, but it's going to be going all the way down my hallway. I already have one extension cord in the hallway, and it's to feed my server from a different circuit. It's not too bad if I keep the overhead lights off.

[tekkydave]

What type of SSR are you using. Check if it is a "zero crossing" type which only turns on/off at the mains zero-crossing points. May make a difference?

Also a lot of the cheap ones are fakes and are lower rated devices in a fake enclosure. Could be worth trying a different device from a reputable supplier.

[zapta]

@tekkydave said in Mains bed pwm frequency/flickering lights.:

Check if it is a "zero crossing" type which only turns on/off at the mains zero-crossing points

What is a good way to check this? Will an AM radio pick more static?

[tekkydave]

@zapta is there a part number on the ssr?

[zapta]

@tekkydave, I don't know the SSR model, I was asking regarding your suggestion to @Surgikill. Is there a simple way to test if a SSR is zero crossng?

[tekkydave]

@zapta I don't think so apart from the manufacturer's spec.

[Surgikill]

@tekkydave This is the SSR I bought.

https://www.ebay.com/itm/25A-40A-SSR-25DA-SSR-40DA-250V-Solid-State-Relay-Module-Alloy-Heat-Sink/401478280169

Probably a fake. I paid 9 bucks for it back in 2019.

[Phaedrux]

Why buy a fake for 9 bucks when you can get a real one (25A) with certification for 9 bucks?

https://www.auberins.com/index.php?main_page=product_info&cPath=2_30&products_id=9

or the 40A for 17$

https://www.auberins.com/index.php?main_page=product_info&cPath=2_30&products_id=30

I have this one by the way.

[Surgikill]

@Phaedrux Probably because this is the first time I've heard of fakes, and every time I looked up genuine ones they were 35 bucks.

[Phaedrux]

It was really bad a few years ago.

https://www.instructables.com/The-inner-workings-of-Counterfeit-FOTEK-SSRs/

[Surgikill]

@Phaedrux Great. I have like 4 of these SSR's in various projects, some using 220V and high current. Can't wait to see if any of them explode.

[tekkydave]

I discovered I had a fake Fotek SSR on my 750W 220V heatpad. It looks genuine but I only paid a few quid for it on ebay. To be fair it was doing its job but I didn't want to take the risk.

I replaced it with this one from a reputable supplier (RS in the UK).