Is the CIM COOLER Good for use?

[Gadeer Zbedat]

what is the pros and cons for using the cim cooler?\
please reply me !

[yash101]

Well, it is forced-air-cooling and the fan won't stall when the motor stalls, so it seems to be quite genius of a design. However, I haven't tested it.

The only problem I see is that since it enclosed the CIM, I think it may block off the radiation waves (don't be scared of that :D), to cool down. I think that might make it less effective in cooling itself down.

CIM's don't necessarily run too hot. Our drive motors don't have heat sinks. I haven't seen a single one overheating. However, that could be because we are using mecanum so the motors keep moving even if the robot is stalled, another pro for mecanum! :D

[MrBasse]

Well, it is forced-air-cooling and the fan won't stall when the motor stalls, so it seems to be quite genius of a design. However, I haven't tested it.

The only problem I see is that since it enclosed the CIM, I think it may block off the radiation waves (don't be scared of that :D), to cool down. I think that might make it less effective in cooling itself down.

CIM's don't necessarily run too hot. Our drive motors don't have heat sinks. I haven't seen a single one overheating. However, that could be because we are using mecanum so the motors keep moving even if the robot is stalled, another pro for mecanum! :D

I think you are thinking of the "Ice Box" for 775 style motors. That is a powered fan and full enclosure for the motor.

The CIM cooler is just an aluminum heat sink that attaches on to the outside of a CIM motor. It will definitely make it easier to remove some heat by adding surface area, but it also takes up some space and weight. We have never needed to cool our drive motors and have never noticed a loss of power from not doing so. However, there could be some advantage to it if you were dependent on consistency in drive (i.e. moving forward for a set time in autonomous rather than using encoders). That being said, our CIMs get hot to the touch and taking some heat off of them is on our list for this year, just not very high on that list.

Honestly we might just use a few of the fans out of our pile of collected fans if we have time.

[apalrd]

There were two coolers in the kit:
-The 'ice chiller' blue 550/775 cooler, which is a great looking design as the motor is open, allowing air to pass through the motor and cool the hot parts (esp. the armature).

-The CIM heat sink, which looks like a piece of extruded aluminum.

The CIM heat sink will do relatively little to cool the CIM as there is almost nothing in the CIM to transfer the heat from the armature (which spins) and the case (which does not spin). I like to look at This Data (http://www.chiefdelphi.com/forums/showthread.php?p=1215913#post1215913) for an example of how different the internal temperature is. As you can see in the first PDF the brush guide temperature (green) is way hotter than the case temperature (orange) over the period of a match, and stays hotter for almost 20 minutes of heat soak.

That said, I have seen benefit to fan cooling CIM motors for longer periods of time on practice robots. Some teams that I know build a simple fan holder that sits somewhere on their robot (they hang it from the bumper with the robot tipped on it's side) to cool the CIMs when the robot is not on the field.

It's not that the CIM does not run hot, it's that you can't feel it on the outside.

[Tungrus]

For effective heat transfer between CIM (or heat source) and the heat sink, both should have max contact area possible. The heat sink in the kit does not contour to CIM curvature (at least the one I saw), reducing effective heat transfer, which is in addition to paint on the CIM. To maximize the heat transfer there are compounds, a paste that goes between the heat source and sink. Not sure if using heat compound will be considered as tampering, in my opinion it should not, thats for Q&A.

Having said that using this heat sink with some contact will result in better cooling than no heat sink. The fins provide larger surface area of heat dissipation.

[MichaelBick]

It's not that the CIM does not run hot, it's that you can't feel it on the outside.

Based on our experience, we've had CIMs run really hot during practice. Our conditions were a bit more extreme than most. We were geared for 18fps, and after about 15 - 20 minutes of practice the CIMs would get really toasty, noticeably affecting performance. Fans really helped us in this situation.

[Doc Wu]

In a 2-3 minute match, the CIM motors don't have time to get very hot. What we've noticed is that the worst conditions for them are during practice and demos when they are driving for longer periods of time, especially as they get used under low battery conditions.

As another poster said, the source of the heat is deep in the windings inside the motor and it takes quite a while for it to migrate to the outside of the case.

That doesn't mean that it's not of some benefit to remove any heat you can from them, but it's probably too little, too late for typical match use.

If I were going to install them on a CIM motor, I would use a heat sink compound, much like the heat sink on a CPU or transistor. The paint on the case would be a consideration as well, but with the narrow views of what is considered a "modification" in the rules, I'd be afraid removing paint might be a problem. Even the silicone compound might get questioned.

I'd save them for the practice robot.

[nuggetsyl]

Cims do get hot and we have made heat sinks for team 25 and use them on the cims. Imo 80% of the teams do not understand how this game will played. This is not 2012 there is no safe zone. Imo this is the second coming of 2003. If you are a defensive robot and have the weight get some heat sinks.

[yash101]

They aren't too heavy either. I beclieve they are under a pound, so just use them on some high-strain parts, like the drivetrain.

[Gadeer Zbedat]

I'm really thankful for youre replies guys :)
Good luck in competition and have great building season \
Team 1946

[Vaude]

The coach of my team actually owns Next Gen Robots, the company that owns the CIM coolers, which came in the KOP.

To demonstrate, he did a 3 minute test of CIMs under no load, and you can see they make a huge difference. once you think about what kind of load your teams may be putting on these motors, you'll see they are well worth the additional weight.

www.youtube.com/watch?v=O-A6PXVUmW0

I can direct questions you may have to him, when my team meets tomorrow.

[RobotDoktor]

It can depend on your usage. Drive motors may not necessarily need it except during extended use or very high load. Our team's 2013 bot used a CIM to power a flywheel based shooter, which did get so hot in a demonstration/practice period we had to stop using it to avoid damage (oh, by the way, burning CIM is a bad smell). Any CIM that is under near constant use, especially on a PID, can definitely benefit from this. As to the overall effectiveness, it may not be as good as active cooling, but is simpler. The shell of the CIM is aluminum, so when the motor is hot enough it will conduct heat. Without some sort of thermal paste to aid the conduction between the CIM and the heatsink may not be totally efficient.

[roystur44]

The Banebot motors in a start stop high load conditions can get smoking hot. I've seen the power wires get red hot and melt the covering off. Wonder if there will be any heat sinks made for them???

[Vaude]

In continuation with my previous reply, my coach put the data from the video, which proves the effectiveness of the CIM coolers Here (www.youtube.com/watch?v=O-A6PXVUmW0)

After many requests, he also made a chart which lays out the temperatures Here (http://store.nextgenrobots.com/product/active-cooler-fan-shroud) (Select the second image, linking to the image itself resulted in a rather small image).

I am currently at my team meeting, so let me know if you have any questions!

[NextGenRobots]

Here's a snapshot of FRC TEAM 4283 with triple motor Gearboxes and Full 360 CIM COOLER configuration!

https://scontent-b-iad.xx.fbcdn.net/hphotos-ash3/t31/q72/s720x720/1911196_747197228626821_704511354_o.jpg

More shots of their build and Week 0 competition can be found at https://www.facebook.com/GranvilleRobotics. Thank you TEAM 1038 Lakota Robotics for hosting this past weekend in Cincinnati.

-Dan

[ausinhanks]

we are looking for more of these sim coolers and i was wondering if anyone knew where to buy them thanks

[Robo Hamsters]

we are looking for more of these sim coolers and i was wondering if anyone knew where to buy them thanks

http://store.nextgenrobots.com/product/cim-cooler-360

[MrForbes]

We switched to the little Viair compressor this year, and like many other teams added a big fan to keep it cool. Since the compressor is in the middle of our robot, between the drive motors, it also happens to keep the outside of the drive motors cool. No heat sink required.

Your mileage may vary.

[Jarren Harkema]

We switched to the little Viair compressor this year, and like many other teams added a big fan to keep it cool. Since the compressor is in the middle of our robot, between the drive motors, it also happens to keep the outside of the drive motors cool. No heat sink required.

Your mileage may vary.

Same sort of set up for us as well. We are using a server fan which blow air across the compressor and cims on the left side. This worked so well we mounted a second fan on the the other side to keep the right coms cool.

[Mason987]

If I were going to install them on a CIM motor, I would use a heat sink compound, much like the heat sink on a CPU or transistor. The paint on the case would be a consideration as well, but with the narrow views of what is considered a "modification" in the rules, I'd be afraid removing paint might be a problem. Even the silicone compound might get questioned.


I'm not 100%, but i was looking at the bag those heat sinks come in and they suggest using a compound themselves. We aren't using them so we won't run into this problem but I would imagine some thermal paste on them would be acceptable. Without the paste, the aluminum isn't transferring the heat as well, obviously enough. I'd imagine driving around and letting the air do the cooling might even be more beneficial than a heat sink without the thermal paste.

I could be wrong though. :p

[Nathan Streeter]

As has been mentioned by Andrew Palardy and others, a heat sink will probably have relatively little impact on the motor winding temperature over the course of a 2-3 minute match... See Richard Wallace's data for evidence regarding that (note how, during the test, the motor case temp only rises by about 5-10degC).

Where I do think a heat sink would make a difference - and I think it would - is when you put the usage in the context of practice, elim matches, or short match-turn-around (i.e. districts or off-season), etc. The internals of the motor can't be cooled below the CIM case temperature... so as the external motor housing climbs to higher temperatures, so also do the minimum and working internal temps (since under same power output conditions, the same deltaT will be maintained from motor windings to CIM case).*

So, I definitely recommend that teams consider how to cool their CIMs! I know I'd like to work out a way to put a heat sink solution on our robot!

I haven't used the CIM COOLERS but they look like a neat solution... I do have a few comments about them though:

-The linked video test is neat, but running at free speed is fairly low heat output (32W)... At max power they dissipate 477W, and at stall they dissipate a mind-blowing 1596W**! At only 32W, simply adding aluminum to the case to hold more heat for a given temp increase would have a beneficial impact.

-Heat sinks rely on air taking the heat away... hence the fins. Without a fan (forced convection), it relies simply on the air moving around... which is driven by the fact that air becomes lighter when it gets hotter. In the test the fins are vertical (ideal), while on almost all robots they are at all angles (vertical, horizontal, upside-down)... this means its effectiveness will be significantly lower when mounted horizontally, particularly in a cramped robot.

- If teams use the heat sinks, they should definitely apply thermal paste (I've had experience with silicone grease and other gap fillers... i.e. http://www.bergquistcompany.com/thermal_materials/gap_filler/gap-filler-3500S35_properties.htm). Interfaces are tremendous thermal insulators... applying a little thermal paste and then bolting the heat sinks together firmly enough so that paste squeezes out will help tremendously. With many Watts being dumped through that interface, you could have a huge thermal rise just in the interface (let alone the motor internals). I wouldn't be surprised if using the CIM COOLER with no thermal compound gives little or no benefit. If you do use a thermal paste, I highly recommend the blue stuff from Bergquist... compared to grease it's extremely easy to cleanup!


So, I would recommend investigating a CIM-cooling solution... but putting some big muffin fans on there to run while the robot's on or off may go about as far (note, the robot's usually on the cart far more than it is powered on). You'll likely want fans somewhere to force the air around, rather than relying on free convection.

*If you're interested in a tidbit about heat transfer... it works the same way electricity does. In electricity, a Voltage drop (i.e. deltaV between two battery terminals) drives/pushes electrical current (I) to move against electrical resistance (R). Similarly, a Temperature drop (i.e. deltaT between CIM internal and CIM case, then between CIM case and ambient) drives heat to move against thermal resistance.

** Note, 1596W is nearly as much as an oven puts out, and well over that of a microwave! Now that certainly motivates me to cool my CIMs and avoid stalling them!