Unique 200A ESC cooling system

[Jeepers]

With all due respect to the OSE scientists, I think I'll just continue to run my equipment at or just below their specifications.

Last week I had to replace a 208v 3 phase 1 hp evaporator fan motor in a -20'F warehouse freezer. The stator was cooked.
I wonder how that happened at that temperature??

Doug

Thats because it was not cold enough you need to super cool it -40'F or colder and you need to run on Lipos and get rid of those Nimh's you have been using lately, the voltage sounds a little low you need to go to 440v 3phase!.

[Steven Vaccaro]

With all due respect to the OSE scientists, I think I'll just continue to run my equipment at or just below their specifications.

Last week I had to replace a 208v 3 phase 1 hp evaporator fan motor in a -20'F warehouse freezer. The stator was cooked.
I wonder how that happened at that temperature??

Doug

Doug I found something for you.

[Doug Smock]

Doug I found something for you.

Oh man!!!!!!
I didn't mean to sound grumpy, just trying to expose a bit larger picture.

I guess I should go take that nap.

Doug

[befu]

My take

I like this research becasue it gives me different options for the way I run.

I am not into real high power setups. 6s or less and under 90 amps. Hopefully well under 90 amps!

I pot the recievers (AM ones) in epoxy so they will not get wet. The other option is to put them in a radio box like the old days.

Do not worry about the motors getting wet, the ESC is potted in epoxy so it can get wet if it flips.

Servo, need to waterproof by coating the circuit board or using corrosion X. I will have to test my hobby king servos to see if they work under water with corrosion X.

Batteries: This is the last item of concern then. If they get wet, I let them dry out for a day or two before chargin them. I get around this and I will not have to tape a hatch ever again!

I look at this research so much because it helps to make a sport boat so much easier and funner to run.

Thank you and keep it up,

Brian

[questtek]

There is a difference between old servos and the newer servos. The feedback pot in the old servos had a much lower resistance than in the newer servos. Thus what works for an older servo will usually not work for a modern servo. The newer servos (using a lower pot current) can fail when wet by running to one end and burning out, while the older servos work fine. Also, salt water on a newer servo plug will stop operation after a minute or so as rapid battery-driven corrosion happens (much faster than normal water driven corrosion.) Of course, one logically uses an older (expendable) servo to test with. I am up to about a dozen burnt ESC's, so I like what you are trying to do.
Also, does the fan air get into the Tupperware (ie: could water get in?) or is there an undiscussed seal between the inside and outside. Thanks

In terms of the new vs old servos you are "SPOT ON". I went to the local hobby store and bought a brand new HiTec servo. The video below compares the two servos. The old Futabas may now increase in value!

http://www.youtube.com/watch?v=RhbU2E129zA&feature=youtube_gdata

In terms on the arrangement of my cooling, I attached a pic with all the parts. The tupperware top has an opening so the fan can cool the heat sink. The Delrin plate and long screws hold the arrangement together insuring the heat sink is in contact with the FETS. Pretty simple with plenty of room for improvement.

[questtek]

I like this research becasue it gives me different options for the way I run.

I am not into real high power setups. 6s or less and under 90 amps. Hopefully well under 90 amps!

I pot the recievers (AM ones) in epoxy so they will not get wet. The other option is to put them in a radio box like the old days.

Do not worry about the motors getting wet, the ESC is potted in epoxy so it can get wet if it flips.

Servo, need to waterproof by coating the circuit board or using corrosion X. I will have to test my hobby king servos to see if they work under water with corrosion X.

Batteries: This is the last item of concern then. If they get wet, I let them dry out for a day or two before chargin them. I get around this and I will not have to tape a hatch ever again!

I look at this research so much because it helps to make a sport boat so much easier and funner to run.

Thank you and keep it up,

Brian

Thanks and I really appreciate all the comments. You may want to see my video on old vs new servos submerged. Quite interesting results and somethink I did not expect. You may not have to test your Hobby King servos after all if they are the newer variety!

[Jeepers]

Ok I missed something what made that servo sluggish? It was slow on the bench before entering the water, did the Corrosion X do that?

just want to make sure I am on the same page here.

[questtek]

Ok I missed something what made that servo sluggish? It was slow on the bench before entering the water, did the Corrosion X do that?

just want to make sure I am on the same page here.

The new HiTec I purchased was fine and operated per normal until I saturated it with corrosion X. D. Smock was kind enough to PM me this insight and the reason for it being sluggish after the corrosion X treatment.

"I'm guessing that you saturated the commutator in the Hitec servo with corrosion X is the reason it was sluggish even before it was submerged.
IME brushed motors don't like corrosion X"

Looks like the recommended technique is to possibly conformal coat the circuit board and keep the servo as dry as possible. On the other hand, even after almost 10 hours of continued sumbersion in tap water the Futaba servo is doing fine with the same response it had just out of the box.

[Jeepers]

I was kinda of thinking that as well, considering that Corrision X is dielectric,but I kept wondering if I was missing something like if it had to do with your servo tester (never used one of those) or if it was the servo.

[questtek]

I was kinda of thinking that as well, considering that Corrision X is dielectric,but I kept wondering if I was missing something like if it had to do with your servo tester (never used one of those) or if it was the servo.

I used an E-Sky servo tester that could control two servos at one time. I had both the old Futaba and the new HiTec connected to it. It was not the servo tester since, if you see the video I posted, the Futaba acted normal but the HiTec moved very slow and slugish. I think the reason given in the previous post is probably accurate.

[Jeepers]

I used an E-Sky servo tester that could control two servos at one time. .

ahh I did miss something in the video, I thought you had 2 of those E-Sky testers I was to busy watching the servos.

I need to sleep more......... maybe I would catch stuff like that.

[old guy]

OK this my be stupid but I'm old and stupid so here goes. Way could I not just put all my Electronics in a radio box like I did with my nitro boats and fill it with oil and run some cooling tubs in to cool the oil. now every thing is water proof and the ESC would be cooler. is this to off the wall or what
Old Guy

[questtek]

OK this my be stupid but I'm old and stupid so here goes. Way could I not just put all my Electronics in a radio box like I did with my nitro boats and fill it with oil and run some cooling tubs in to cool the oil. now every thing is water proof and the ESC would be cooler. is this to off the wall or what
Old Guy

You are totally ON and NOT off the wall on your comments. For the past thirty plus years submersibles for ocean research have all been using oil filled motors and oil filled electronic housings. This includes the Russian Mir submersibles that made over 100 trips to the Titanic and the the US titanium hulled Alvin that is operated by Woods Hole.

My testing and experience with FE electronics is that this is perfectly feasible with some exceptions. Motors and ESC's have absolutely no problem. I keep them in a mineral (NOT motor) oil bath and run a cooling fan. You could also put them in a mineral oil bath and also run conventional tube cooling. I imagine many FE guys do not want the extra weight of oil and container, additional room they take and the mess is the oil spills. On the plus side, you never have to worry about shorting the ESC from water intrusion and the cooling is much better since 100% of the electronics are in contact with a thermally conductive fluid not just the top of the outer board of FETS. Like everything in life...it's a personal trade-off.

In recent tests I tried putting the ESC in tap water after treating with Corrosion X. Bad idea because the water did have ions which caused shorting and the ESC to burn up. This would NOT have happened if I stuck to the convential mineral oil bath I normally use.

I also treated an old Futaba servo with Corrosion X and totally sumberged it in tap water. It operated perfectly even after three full days of continued submersion in tap water. It was pointed out this will not work with newer servos. I tried it on a new HiTec and it does not. The Corrosion X slows down the servo motor. It still operates but now takes 6 seconds to travel 60 degrees. (Perfect for a slow moving video pan and tilt servo but that's about it!)

I have not tried receivers since I keep them in a rubber balloon for ease of changing the connectors but I see no reason why they could not be submerged in non electrical conducting mineral oil also. They do not over heat so the resason would be to prevent any type of water damage...but this can also bedone with conformal Silicon coating or Corrosion X.

I attached a pic of a 2000 foot depth rated submersible I operated with all motors and electronics in oil filled housings. Operating at 2000 foot depth in seawater is a bit more challenging that the electronics in a small FE surface boat but your idea is totally sound and feasible. The yellow sub has a depth rating of 1200 feet and we are currently operating this off Catalina island. Again, totally oil filled motors and electronics.

[rearwheelin]

Has there been a thread on a successful setup on here with testimony to esc gains?