I purchased an ESC and a Speed 400 motor about 17 years ago with the intention of building my first electric powered model plane. Life took its various turns though and my time for R/C modelling dried up soon afterwards. Now that I have 3 boys who are all starting to show interest in the area, I've started to find the time to look at it all again... yay!

Part of the reason I never got to build that electric plane originally though was that I had no means of connecting the motor to the plug included on the ESC. I know I could just cut the plug and replace it, but I've been trying to identify the type of plug without success for a while now.

Can anybody tell me what the type of the red plug in the image below is?

enter image description here

As an aside, I'm a bit mystified by the battery connector, since it has 16 guage wires onto the ESC, but then connected to much smaller guage wires with a JST plug. I don't have any specs on the ESC itself unfortunately, so don't know what the rated current is and consequently whether or not I should be concerned about those wires!


2 Answers 2


That looks like a 4 pin Deans Micro Plug, which goes by WS Deans part number 1242.

Regarding your wire thickness, as you say it all depends on the expected current. If you can identify the current rating for the smallest wire in the circuit, you could add a similarly rated fuse and do some bench testing and current measurements - and if the fuse blows, then the wire probably would too and should be replaced.


I agree, it looks like a Micro Deans plug. They're good for about 10amps. A red JST plug is good for about 5amps. A speed 400 is pretty inefficient over about 5amps.

Personally I'd junk both the ESC and motor and go brushless. You'll save weight, gain efficiency, be able to use a bigger prop and it won't wear out. And that ESC probably doesn't have a lipo-friendly low voltage cut-off.

  • $\begingroup$ (@Kralc) Thanks to both of you for the answers there. Yes, I've been thinking it is likely not the most practical power solution at this point in time. Perhaps I'll relegate it to use as a powertrain for a Lego model for the boys or some such thing! $\endgroup$
    – John Rix
    Commented Jun 25, 2020 at 13:53
  • 1
    $\begingroup$ Old brushed ESCs are also useful as a switch for lights, or even just for the BEC. $\endgroup$ Commented Jun 26, 2020 at 7:18

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