Duet 3 6HC & Mini 5+ & 2x part fans only one starts reliably

[blt3dp]

Hi, I've got 2 setups.

One is a Mini 5+ with 2 fans connected to either OUT5 or OUT6 a special made 300mm cable that's split off at the end to both fans. The fans are these https://kb-3d.com/store/fans/3-3010-ball-bearing-blower-fan-24v.html

The other is a 6HC with a Smart Effector, a 600mm cable from the board to the Smart Effector, then a splitter plugged into that and running to each fan. They're the same fans.

The problem that I'm having in both cases is that if the machines have been inactive and powered off, the first print I run, when the cooling fans are to turn on, only one of them does. All it takes is a small touch to get the other one going.

On the Smart Effector setup, I could potentially see it being the magball arms interfering. But it acts the same on the other setup which is a Voron 0.1, there's no interference there.

I've tried increasing the blip time as well as lowering the frequency from the default 500 to 100

Any ideas?

[Phaedrux]

How much blip time did you give it?

Have you tried a higher frequency?

And just to confirm, these are wired in parallel?

[blt3dp]

@phaedrux

These are wired in parallel.

I just actually had the thought to try a higher frequency, I remember the thread about the e3d hotend cooling fan needing that kind of adjustment. I’ll try something like 5000-10000?

For blip time, I believe I tried doubling it from what I understand is default 0.1 (100 ms) to 0.2 (200 ms)

[Phaedrux]

Yes 5000 to 10000 sounds like a good range to start with. You can go higher still.

For blip time, try a full second and see if it helps.

[blt3dp]

@phaedrux said in Duet 3 6HC & Mini 5+ & 2x part fans only one starts reliably:

Yes 5000 to 10000 sounds like a good range to start with. You can go higher still.

For blip time, try a full second and see if it helps.

On my Delta, I tried the whole frequency range in the Q parameter of my M905 command, I tried all the way from Q1 to Q65000 and none were able to affect the issue other than at one point both fans wouldn't start at all.

I also tried different blip times in my M106 all the way from 0.1 (100ms) to 2.0 (2sec) and it also did not affect the issue.

Happen to have other ideas?

[Phaedrux]

?Do the fans work better individually when not wired in parallel?

[blt3dp]

@phaedrux They do work better individually. Now that I think about it though, I was previously running 12v fans. When I switched over to these 24v fans, I know I set the jumper on the Smart Effector. But now I'm not sure if I actually set the jumper over to VIN for OUT 7-9 where I have the fans on OUT 7. I'll double check that and make sure 24v is actually getting to the fans.

I do also have a concern these little fans are really affected by the magnets in the arms. Though it does act the same on the Voron where no magnets are near the fans.

[Phaedrux]

With small fans like that it could come down to luck of the draw.

[blt3dp]

@Phaedrux

I just did some testing on the Voron 0.1 and it acts the same way still. Definitely no magnets interfering. I wouldn't think these fans would be the spec'd fans there if they wouldn't work. The only real difference in my setup there is that instead of their recommended control board, it's the Duet.

I also went back to my Delta, and moved the fans from Out 7 to Out 4 and it seemed to work. Though, it may be because I had been messing with them for a while. I'm going to power it off for a the night and see how it acts in the morning.

Any ideas why that would work, if it weren't just lucky timing with me playing around with them?

Edit: Just tried to start them again and one wouldn't start, bumped the frequency up to 15000 and they wouldn't start. Dropped it down to 10000 and they started. I'll power it off and try in the morning to see.

Edit Again: Just tried again and one wont start.

[dc42]

@blt3dp if you are using the facility to provide a full power blip to start the fans, and the blip is long enough to start the fans, then the frequency is not relevant to whether they will start or not.

[blt3dp]

@dc42 I just woke up and powered it on and tried to start the fans with M106 S255 and nothing, you can see them move slightly but it's like it's not enough to overcome friction to get them started. I tried boosting the blip up to 5.0 and still no go.

[infiniteloop]

@blt3dp said in Duet 3 6HC & Mini 5+ & 2x part fans only one starts reliably:

tried to start the fans with M106 S255

Using a multimeter, what voltage do you get after calling M106 S255? The reading should be near 24V.

[blt3dp]

@infiniteloop it measures at 24.2V

[infiniteloop]

@blt3dp said in Duet 3 6HC & Mini 5+ & 2x part fans only one starts reliably:

it measures at 24.2V

That's fine. So, either you wired the two fans in series, or the one which doesn't start is defective. At a PWM of 255 (S parameter of M106), the pin is constantly powered.

EDIT: There's another possibility: do you control the fans thermostatically? How are they set up (maybe with a thermistor) in your config.g?

[blt3dp]

@infiniteloop they’re definitely wired in parallel. I measured the voltage on both “legs” of the splitter. 24v definitely getting to both fans.

I don’t do any thermostatic control of those fans, they’re gcode controlled part cooling fans.

They’re both good, it’s random which one will start while the other doesn’t. Sometimes it flips between.

And if I give the non starter an manual push it kicks up and moves just fine.

[infiniteloop]

@blt3dp

They’re both good, it’s random which one will start while the other doesn’t. Sometimes it flips between. And if I give the non starter an manual push it kicks up and moves just fine.

Every fan I know turns happily by itself if fed with its nominal voltage. You can test that when you attach both fans (wired in parallel) to the PSU directly. If one of them still needs a push or starts slowly, there’s something wrong with the fans - else, they don’t get enough current from the board. In the latter case, I would appreciate a photo of the board with connector so I can see which wires go to what pins.

[blt3dp]

Just coming back around to this, I've found it's the fans spec'd for the v0, which are gdstime 3010. They're known to die after being exposed to the heat from the chamber % hotend.

https://github.com/VoronDesign/Voron-0/issues/121

I've swapped them out the the Winsinn fans suggested and they seem to be fine now.

bmgoncu created this issue in VoronDesign/Voron-0

open 30mm blower fans sensitive to the hotend heat and stops working #121