[Solved] e3d heatsink fan turns off during heat up



  • Hello everyone,

    I have migrated my Anycubic i3 Mega to the duet wifi board over the weekend and I must say I'm very impressed with the quality of the hardware and the firmware. It's worlds better than the original board.

    I have noticed that e3d heat sink cooling fan turns off while the nozzle heats up. Once the nozzle reaches the desired temperature, the fan starts spinning again but it has a "hum" to it. The fan is connected to the pwm fan1 output.

    I have tried plugging it to an always on fan socket but it does the same thing, except the humming.

    The fan is 40mm 12V pwm computer fan (3 wires) but I only use 2 wires.

    I would like to have the fan on whenever the hot end exceeds 45C but have no clue how to do it and could not find the answer here. I am using firmware v2.02 RC2 and here is the fan config section

    ; Fans
    M106 P0 S0 I0 F50 H-1                             ; Set fan 0 value, PWM signal inversion and frequency. Thermostatic control is turned off
    M106 P1 S1 I0 F50 B1 L1 H1 T45                          ; Set fan 1 value, PWM signal inversion and frequency. Thermostatic control is turned on
    M106 P2 S1 I0 F500 H1 T45                          ; Set fan 2 value, PWM signal inversion and frequency. Thermostatic control is turned on
    
    ; Tools
    M563 P0 D0 H1                                      ; Define tool 0
    G10 P0 X0 Y0 Z0 U0                                 ; Set tool 0 axis offsets
    G10 P0 R0 S0                                       ; Set initial tool 0 active and standby temperatures to 0C
    

    Any help is greatly appreciated.

    Cheers!



  • Are you sure that the fan is PWM? PWM fan should have 4 wires.



  • You are right. It's not a PWM fan. It's just a normal 3-wire computer fan.



  • You have connected 2 wires and third is unconnected? Fan voltage? Jumper setting for FAN_VIN?



  • @briskspirit Yes. The fan is a 12V fan. I connected fan VIN (the red wire) to FAN1 V_FAN and fan ground wire to FAN1- . There is no jumper on FAN_VIN.

    Hmm... This jumper selects the input voltage according to the schematic. It's not quite clear to me why my fans work, even though I have no jumper at all.

    I will test it out this evening. I think you might have fixed the problem.

    Thanks for your help.


  • administrators

    It sounds to me that your fan is wired incorrectly. Does the machine use a common +12V or +24V wire to both the hot end heater and the heatsink cooling fan? If so then swapping over the 2 wires that connect to the E0 Heater terminal block on the Duet should fix it.



  • @dc42 I unplugged all the fans and motors and I did some testing after connecting the fan VIN jumper and confirmed 12V on the fan pins.

    • Tested the heaters => all OK
    • Connected one fan via the anycubic harness and undervoltage/temperature exceeded errors started popping up for all the drivers. This behavior was absent when the fan VIN jumper was absent. There was something which was shorting VIN to GND. I could hear the power supply clicking as it was protecting from a short.
    • Connected a fan directly to the fan pins (no harness) and things were working as expected

    I think that you are correct because Anycubic uses a wire harness and a PCB to distribute V+ (which arrives though multiple parallel, thin wires) among the fans and the heater block. The GND path is individual for each fan.

    So, yes, I think reversing the heater wires would have worked too but of course that's not what I did because I just saw your message 🙂

    In order to fix the issue, I added an additional wire directly from one of the 12V fan pins all the way to the two fans.

    Am I correct to assume that the 12V fan pin can handle the current from both fans simultaneously?


  • administrators

    @llamazen said in [Solved] e3d heatsink fan turns off during heat up:

    Am I correct to assume that the 12V fan pin can handle the current from both fans simultaneously?

    Yes. The fan outputs can handle up to at least 2A, although if you go above 1A then you should replace the 1A blade fuse by a 2A or 3A one. 12V brushless DC fans used in 3D printer typically draw no more than 250mA.



  • @dc42 Cool thanks!


 

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