On today's episode I'm gonna install this 12-volt Noctua fan in place
of the 24 volt stock fan on this Ender 3. Will it work?
Well let's find out, right here at Filament Friday. This week's episode of
Filament Friday is brought to you by these patreon supporters. This is the
Noctua fan I'm gonna use, it's a 12 volt 40 millimeter by 10 millimeter. I haven't
been able to find a 24 volt Noctua fan. The Ender 3 requires 24 volts so
it's going to require some modification. Now if you have a CR 10 or a CR 10 mini
those are 12 volt systems so you can install this fan with very little
modification. The fan actually has three wires and it comes with some cables and
some adapters but I'm gonna try and spin it with just the two wires; the black and
the red. The yellow wire I'll show you in a minute what that does. So I'm gonna
connect 12 volts to those two red and black wires and the fan starts to spin.
And I can feel it's blowing pretty good. So what is the yellow wire? The yellow
wire is for RPM. It's an open collector circuit inside this thing so I have to
put a resistor to power and then to that pin. If I connect a scope to it, you can
see I get a nice square wave out of that pin. So a microcontroller could read this
and determine its speed. If I lower the voltage to the fan you can see it starts
to spread out meaning the fan is slowing down so it's a great way to get feedback.
But we're not gonna use it, so we don't need that pin. The fan came
with this cable. It's called the low noise adapter and you just plug it in
series with the fan. When I cut it open I could see it just had a hundred ohm
resistor in series with the positive lead. So it just knocked the voltage down
to like nine volts which slows the fan down. My first thought was why can't I
just put a different resistor between the fan and the power to knock the 24
volts down to 12, but in order to do that I need to know how much current this
thing is drawing. So I plugged my ampmeter in between the power supply and the fan.
My meter says about 30 to 40 milliamps and now I can do some calculations and find
the effective resistance of this fan. I do that by taking the 12 volts of the
fan divided by this current and that'll give me the
resistance of 353 ohms. So if I put a series resistor of about 330 they'll be
about equal it should split the voltage in half. But what about the wattage,
across that 330? So 12 volts squared divided by 330 gives me the wattage or
0.436 watts which is about a half a watt. I didn't have a 330 ohm half a watt
but I had a bunch of 1k quarter watts. So if I put three of them in parallel I get
333 ohms which is close and the wattage is added so I get three-quarter watt,
which is perfect. So here's what I did. I took three 1k's twisted them together and
this will be my series resistor and that should match the resistance of the fan.
So if this works, here's the test. I have my meter connected across the fan. When I
power it up at 12 volts it tells me the fan is seeing 12 volts. But if I break
the circuit and put the resistor in series with the fan, which I'm gonna do
right here, this should divide the voltage in half so I should see about 6
on the resistor and 6 on the fan. When I put 12 on it and sure enough 6 volts
across the fan so now I can run this up to 24 volts and I should have about 12
volts on the resistor and 12 volts on the fan. And there you go 24 volts coming
in a little over 12 volts, 12 and a half volts on the fan so the resistors are
working. But there's one problem. The resistors are getting hot. I can feel
them getting warmer so I put a temp meter on it. 48 degrees C and they were still
climbing a little bit. I just wasn't comfortable with this solution so I
decided I'm gonna go with a different solution. And that's a switching power
supply. This is the one I chose and you can definitely go a lot cheaper than
this, but this one has a voltmeter on it plus it's got three modes. It will tell you
voltage in, voltage out and current draw. And it has an on/off switch so this
is the one I chose to use. And I'm gonna show you how I wire this up to the
Ender 3. The first thing I wanted to do is establish a baseline so I have this
app on my phone I put the microphone near the stock fan and I'm getting about
72 to 73 DB of sound coming out of his fan. I also wanted to know what the
temperature was at the center of the heatsink before I changed fans and this
is little apparatus I've used this in a
previous video. This little PTFE tube goes down in holding the temperature
sensor about midway into a heatsink. Then from the menu I adjusted the
temperature of the nozzle to 230 degrees and let it heat up. After it sat for a
while it was reading 43 degrees C at the center of the heat sink at 230 degrees.
So this is good and I have a baseline to work from. The first thing I need to do
is remove the old fan. There's two screws that hold the fan shroud in place. Once
you get those off you can get access to the fan. Once you've got access to the
fan, there's four screws that hold it in place. Remove those four screws and the
fan should lift right out and I'll save those screws because those same screws
will work with the Noctua fan. The next step was to disconnect the fan from
the motherboard. So I had to take the cover off get to the wires and remove
the two power and ground wires. Then I could pull the fan and its wires all the
way through the sheathing. Once I got that out, now I was ready to install the
Noctua fan. It's got these same holes that'll fit right over the post which is
really nice. So I just placed that inside the shroud and everything lined up. And it
kind of like snapped in place. I put the wire so it would come out the top of the
shroud and then I just used the same screws to hold it. So there they are
screwed in place. So now I can put the fan shroud back on and then use those
two screws to mount it just like I did before. Straight forward so far. The Noctua
fan comes with nice wiring that's all protected so all I did was just strap it
to the existing sheathing. I didn't go inside of it and here's my setup. I added
two red and black wires to the power supply and then the connector going to
the adapter that came with the Noctua fan. So where the two wires were before, I
tighten my wires in place and then just routed it all the way along this, making
sure was long enough to stretch and just tightened everything down. You can see I
extended wires from their coupling, came down to my power supply which is sitting
here at the back of the machine. And here's the test. I was seeing about 62
depending on where I put it. But somewhere between 5 to 7 dB lower. So
it's definitely quieter but it also runs hotter. 46 to 48 degrees C is what I saw.
When you compare it to before, it was about 43. So it's about 5 degrees
hotter inside the heat sink so it's not perfect but it is quieter. And here's a
3D print that I found on Thingiverse to hold my little board.
I want to redesign this so it'll slide into the rail and it's also got a cover,
but I ran out of time to do that so I just used some double-sided tape to hold
it. And then some double-sided tape on the back of the board to hold this in
place. So I can actually do some printing.
This board has three modes, it's got an on and off switch. When I turn it on it
tells me the output voltage 12 volts. I can click the mode button it'll tell
me the current that is drawing, which is zero right now, and then the input, which
is twenty four point two, point three volts. So I'll leave it in the 12 volt
output mode so I always know it's working.
Here's a quick test print to print a knob for my extruder and it worked fine.
So it raised the temperature at the heatsink worst case about four to five
degrees and lowered the sound about seven dB
Is it worth it? I'm not sure it really is. But if you're really into making your
machine quiet, I guess it's the right direction. I'm not sure I'll do this to
any other machines. I'm not really sold that it's that much quieter or worth all
the effort or the cost, but I know a lot of people were interested in this so I
had to try it. So there it is. This is just my experience. If you've got better
experience, let me know, in the comments below.
So if you like what I'm doing here maybe check out some of the other videos that
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Friday.