Safety device on each chanel ?

  • There are solutions with fuses on all outputs and even telemetry warnings to report a short per output :) I use them also, but they only work up to 5A servo loads. This is enough for many planes, but not the really big planes or gas 3D planes. Double the fuses and you have a 10A system, which should be perfect for almost any RC plane.

    So Richard, why should a 10A fuse not work? It would work for ALL planes, but you can make a model with fuses for the users who want them? Size does not increase (much, if any). When a servo shorts i have seen cables melt and burn resulting in a total system shutdown (other cables tied to faulty wire melted also). I understand that providing power is very important in a very high load setup but there should be other options. Yes the smaller servo's and wires do not pull enough current to trip the fuse maybe but then the issue is less important.

    We can also add fuses to the servo cables in extensions, but i would like to see it in a powerbox directly. Then the powerbox can report faulty servo's.

  • Hello,

    because this Polyfuses are not very reliable and they have huge tolerances in cut off current. They also have a large voltage dropout in high currents. The fuse technology is based on warming a silicon which turns off when it get´s too hot, for this of course it must have a certain loss!

    Also for 15-26 servo outputs the space demand would be enoumous!

    I know a lot of failures from receivers from other manufacturers which have this fuses inside. I don´t want to tell the customers: Sorry your plane crashed because the fuse had an failure - but you are lucky: your servowire didn´t burn ;-)

    I know for a non electronics this fuses sounds like the absolute perfect and easy solution: but believe me: they are not!

  • But the Jeti Central Box has fuses.... is that such a bad product? It does not look that big :) Yes i understand the issue of the fuses and the resistance. But they are usable in many planes. Normally there should be a big difference in power consumption between a good and shorted servo. With very high powered servo's there is not and then the fuses are a big problem. Normally my servo's need to be strong but the average load is very low so the fuse has enough time to dissipate the energy. For my flaps i know they have a very high constant load so fuses on those channels is a bad idea. For other servo's, mainly gear doors and nose steering servo's, i would REALLY like the fuse option. So a Mercury with 8 fused and 8 non fused output would be awesome i think :)

    But you keep saying space is an issue.... a 5A poly fuse is a small SMD part that dissipates the heat using the PCB. In all my tests they don't get warm until you really load them (and then they should fail).

    But i think i see the biggest issue: Users. They expect every to work every time. If they have to think about fuses or not it is one more thing to not understand and do wrong.....

  • Hello Tadango,

    I don´t use names but boxes with fuses fail more than known - often strange crashes with only one function not working. The problem is you cannot guarantee this fuses working in series! They are fine in the factory and fail after some time. Also what this fuses absolutely don´t like is peak power... take one and make it between a PWM regulator and a DC motor. A 7A Polyfuse on a 1A Motor will fail after some hours!

    We tested all this things and this fuses are a security risk in that application!