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Power cable questions — Parallax Forums

Power cable questions

T ChapT Chap Posts: 4,198
edited 2019-10-27 15:19 in General Discussion
There are two electromagnetic devices 80' away from a controller. 24VDC. There is a controller board with 2 mosfets that are controlled separately by a propeller(off/on/50%duty). One device is full on for short while, but mostly 50% duty at 17K. The other will rarely turn on at all full, but if it does turn on it will be with the other device full on. The way the wiring is working out, its easier to buy a 3 conductor 16 stranded that a 4 conductor. The driver board that controls both devices has the 24V+ going out to each device straight from the PS, the 24- to the devices is switched to GND via the low level mosfets driven by the Prop. So what if I just send the 24VDC+ on 1 wire, and let the 2 returns be separate since they are being switched on/off/pwm, and save a bunch of wire since its 10 of these runs(10x80' = 800' 16Gauge savings.

Comments

  • kwinnkwinn Posts: 8,697
    Should work, but you may need to compensate for the coil inductance now that it is not a pure DC level. Test it well before installing it.
  • T ChapT Chap Posts: 4,198
    Sorry, nevermind. I just realized there is a separate shunt resister in series with each of the +24 leads for current sensing each device. So it has to be 4 wires.
  • TubularTubular Posts: 4,621
    Why not move the current measuring resistors to measure currents in the -24DC return?
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