24V Hemera fan has two wires, stock fan has three wires--what do?
I've read that the 24V Hemera fan runs faster and has a higher static pressure which is needed for the extruder to work correctly. Specs for the included fan, found online:
Model XYJ24B4010M
Rated voltage (VDC) 24
Startup voltage (VDC) 12
Current (A) 0.06
Speed (RPM) 5500
Air flow (CFM) 4.82
Static pressure (mmH2O) 2.68
Noise level (dBA) 26
Weight (g) 14
The fan included with the Prusa MK3S kit is this one:
Model NF-A4x10 5V
Rotational speed (+/- 10%) 4500 RPM
Airflow 8,2 m³/h
Acoustical noise 17,9 dB(A)
Static pressure 1,78 mm H₂O
Max. input power 0,25 W
Max. input current 0,05 A
Operating voltage 5 V
MTTF > 150.000 h
I tried attaching the Hemera fan with the black wire attached to the left-most pin, as indicated in the Einsy Rambo schematic--the fan doesn't spin at all and I get an error message that the fan isn't working on the display when I try to do a preheat in order to do the hot-tightening step.
What can I do? Thank you for any suggestions or help you may have.
RE: 24V Hemera fan has two wires, stock fan has three wires--what do?
Oh man. You ever post something and then a few minutes later realize how stupid you are? No? Just me? Okay.
Anyway, obviously I need a 5V fan that matches or is similar to the 24V fan that came with the Hemera. 5 volts, because that's what the Einsy board puts out for the hot end fan. Duh.
I'll go search for one online and if I find one, I'll post it here.
RE: 24V Hemera fan has two wires, stock fan has three wires--what do?
This is the fan I decided to try
Sanyo-Denki 109P0405H901
It's a tad beefier than the Hemera stock fan, with slightly higher CFM and static pressure numbers. I expect it to sound like a 70's hair dryer.
RE: 24V Hemera fan has two wires, stock fan has three wires--what do?
Well you are trying to replace a 5 volt fan with a 24 volt fan. Your new one won't even start under 12 volts.
You could power it directly from the PSU, with maybe an inline switch.
RE: 24V Hemera fan has two wires, stock fan has three wires--what do?
Note that without that third wire from the fan there is no feedback to the Einsy about how fast (or even if) the fan is spinning. I'm not sure if the fan feedback is disableable in the Prusa firmware because it is considered a safety feature to make sure the extruder is being cooled properly.
If you know electronics, I suppose you could use the 5V fan output of the Einsy to switch a MOSFET that would control the 24V from the power supply to the fan. If you didn't understand that, than it is beyond your skills. I'm not sure how to simulate the tachometer feedback though.
See my (limited) designs on:
Printables - https://www.printables.com/@Sembazuru
Thingiverse - https://www.thingiverse.com/Sembazuru/designs
RE: 24V Hemera fan has two wires, stock fan has three wires--what do?
@robert-rmm200
Ok, live and learn. Thank you for the response.
I looked over the datasheet for the new motor, but I don't see how to tell that it won't start spinning with less than 12V. If I'm going to find the right fan, that's something I'll need to understand. How were you able to determine that?
RE: 24V Hemera fan has two wires, stock fan has three wires--what do?
The line:
Startup voltage (VDC) 12
RE: 24V Hemera fan has two wires, stock fan has three wires--what do?
I received the fan. It starts and runs as expected when connected directly to the Einsey board. Setup reports no errors.
I still need to finish setting up the Hemera before I can say if it works otherwise. So far, so good.
Thank you for your responses.
RE: 24V Hemera fan has two wires, stock fan has three wires--what do?
If you want to use the fan that came with the hemera use jumper cables to connect it.
+24V goes to the pin1 of J19 connector
Ground goes to left pin of the hotend fan connector
You will have to disable fan check (or something like that) in the menu otherwise you'll get error because fan has only one speed (full blast)
RE: 24V Hemera fan has two wires, stock fan has three wires--what do?
@darrin-brunner Are you still happy with the new fan? Any issues with it?