Two of the new threads in this forum have prompted me to provide a few details on a technology I have been working on for the past several weeks. The threads involve:
1. The Inexpensive Mystery 200 Amp ESC
2. Cooling a motor via water injection
As an ocean engineer and chief scientist for the EXOMOS submersible factory in Dubai, I can tell you first hand that running both PM and brushless motors in a non-conductive oil is standard practice. All deep water submersibles use brushless motors in a non-conductive oil bath, either mineral oil or better, biodegradeable oil obtained from certain flowers.
I run inrunner and outrunner motors in non-conductive oil and even water all the time.
This thread will hopefully get some of the great minds on this forum thinking regarding my approach to making inexpensive speed controllers work: like the sub-$50 Mystery 200 Amp ESC.
I purchased 8 of these units for testing. I have 7 still fully operational and I believe the method I use to cool them has a lot to do with keeping them alive and kicking.
I have included pictures to show how this is done but quite simply here are the following steps:
1. Remove the shrink wrap from the Mystery 200 A ESC and soak in Corrosion X for several hours. Let it drip dry.
2. Build a non-conductive bottom plate and use small but long screws to bolt the esc to a fan sandwiched between the stock mystery heat sink and the lid from a small tupperware container as shown. This permits the heat sink to be firmly mated to the top of the FETS and pulls the fan directly onto the heat sink for optimum cooling
3. Punch, do not drill, holes in the tubberware container top for the motor, battery, control, and thermistor wiring as shown. (The units I use are 2 for $1 at the local 99 cent store)
4. Fill the bottom mating part of the small tupperware container with common mineral oil. It should be at the level of the bottom of the heat sink
5. Attach the top and mount into your FE. Note that I keep the gas engine mounting surfaces in the Mean Machine and design an adjustable motor mount around it. Some simple dremel tool machining provides a perfect fit for my tupperwate, oil-baithed Mystery el Cheapo.
One of the set ups I have been using is a 580 in a Mean Machine. I have made lots of runs on this thing pulling 170 plus amps with no problem.
Concept behind this Technique:
The non-conductive oil provides 100% cover for heat transfer.
The movement of the boat circulates this fluid and provides good heat transfer to the stock heat sink.
The fan pulls the heat out of the heat sink.
The fan is directly connected to the power input terminals of the ESC . ( A normal 12 vdc computer fan will work just fine on a 4-cell LiPo set up.) It continues to run and cool until the battery is disconnected.
I used this ESC cooling set up in the first test of the new Insane Hydro with Mark. Worked great, and the Eagle Tree showed cool temps. Downside was that this new boat cornered so well in the turns that centripital force caused some of the mineral oil to push out the punched holes in the lid for the wires so we had a tiny bit of mineral oil on the bottom inside of the hull. Good because this will prevent the fiberglass from rusting.
Hope you fine this useful and it stirs the imagination with guys like Jeff W. who had been playing with ESC cooling for a bit.
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