# Improving DMOC445 cooling



## CKidder (Dec 12, 2009)

I've actually added liquid cooling to a DMOC445 because the motor does like to overheat even in mild climates. It's such a weak motor that I got the inclination to try to push it a bit too hard and that made it overheat.

Anyway, what I did was buy little shapeable metal tubing and run it in the fins of the motor back and forth (that isn't easy to do without kinking the tube but it's possible). The tubes were glued in place with thermally conductive epoxy. This was done in quadrants so that there were four runs of tube. I ran coolant through all these tubes and back to a small radiator with a fan on it. This whole thing did help with heat. But, it's a lot of work.


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## halestorm (Apr 28, 2009)

Sounds like you are cooling the motor, not the controller, but that sounds like a good idea, too. I could perhaps do something similar for he DMOC, drill holes to run cooling lines through the base of the fins. What I said seemed too extensive/risky was getting to the plate beneath the fins, where it matters most. Cooling lines in the heat sink fins would be less effective but may still work.

Now back to the motor...do you have any pictures of what you did? Also what is your liquid heat exchanger, a radiator, reservoir and a pump? Any pictures of that?

While I agree that additional cooling of the motor is good, it's the DMOC I believe that is getting too hot in my case.


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## hmincr (Jan 20, 2012)

Have you ever heard of 5200 3M marine sealant? If not get a tube and smear a little anywhere water MIGHT seep inside the controller. Once dry, 24-48 hours, I guarantee water will not get inside that controller. It could be submerged, if sealed properly. 

Might be a bit of work to remove, if the controller ever needs worked on, though. It's a rubbery type sealant, and can be cut with a very sharp knife.


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## coleasterling (Feb 29, 2012)

Can you post some pictures of what the DMOC looks like? Is it possible to drill/machine some cavities in the heat sink base if you had access to a mill?


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## halestorm (Apr 28, 2009)

Here are some pictures of the DMOC445 that I pulled from Google images.

Here is the DMOC user manual, which shows some drawings.

This one shows both the air- and water-cooled models:









Here is a closer look at the air-cooled model I have:









Let me describe it a little. Inside that box in front of the heat sink are the two DC input connections and the three motor output connections. These connections pass through the top plate. The heat sink fins are part of the top plate (I.E. not screwed in, but integrated, one-piece). The IGBTs are attached to the back side of this plate.

I don't think I need the 3M marine sealant; I'm not too worried about water getting in, as all of the connectors are hermetic, and there is an O-ring around the plate where it attaches to the controller body. Although, I could use some sealant just to be safe. Probably the least-protected item would be the fans (although I think even the fan power connectors are hermetic).

I am a little concerned about operating the controller with the fins upside-down.


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## Tesseract (Sep 27, 2008)

halestorm said:


> ...I am a little concerned about operating the controller with the fins upside-down.


Heatsink fin orientation is irrelevant when using forced convection (ie - air forcibly blown across the fins). That said, the water-tightness of the AzD enclosure depends to some extent on gravity (ie - water should not be allowed to pool up around seal interfaces).


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## halestorm (Apr 28, 2009)

Tesseract said:


> Heatsink fin orientation is irrelevant when using forced convection


Ok good, that's what I was thinking but wasn't sure. It will be protected from water above, because it will be mounted directly under a battery box. It will only see road splash from below, and of course road debris, and grime. I can protect against debris with a sheet of perforated steel. I think I'm going to do this (change the mounting location, that is).


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