Motor Connector Rating



  • Hi,

    I'n looking into getting the DuetWifi controller for a custom build and a question popped into my head which I was hoping could be answered here.

    (Apologies in advance if this issue has been discussed before on this forum, but there were simply too many threads to go over and find out).

    My question refers to the motor power headers on the board and it's essentially this:

    The listing for the DuetWifi (https://www.duet3d.com/DuetWifi) states that:

    High Power rating: Each stepper driver is capable of 2.8A motor current, currently limited in software to 2.4A.

    However, looking at the actual connectors on the board itself, they seem like regular 4-pin fan headers.

    Admittedly, it's very hard - if not impossible - to get any reliable information regarding the power rating of this kind of headers, especially as there's no industry standard and potentially different brads will have different ratings.

    And yet, from what I remember, conventional wisdom typically puts the figure at around 1A max per header.

    If this is indeed the case (and, again I don't know so I'm asking here), isn't there a danger in using this kind of headers for this particular purpose?



  • They're Molex KK Wurth Elektronic WR-WTB series which are Molex-KK compatible connectors, good to 3A. Even if a Dupont connector was used, those are generally good to 3A.



  • The latching headers used on Duets are actually Wurth Elektronic WR-WTB series which are Molex-KK compatible, but only rated to 3A. However we have never had a report of one burning out in service.


  • administrators

    Last time I looked, the genuine Molex KK connectors were only rated to 3A too. That's why we don't use them to connect the extruder heaters.



  • 3A rating sounds good to me 🙂

    Thanks for all the comments and clarifications!



  • @Roland:

    The latching headers used on Duets are actually Wurth Elektronic WR-WTB series which are Molex-KK compatible, but only rated to 3A. However we have never had a report of one burning out in service.

    Nice catch, Roland! Sorry, was thinking of Molex MicroFit I think.


 

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