VIAIR 250C-IG Compressor

[ArtemusMaximus]

We found this compressor that by the looks of it meets requirement of FRC rule book for 2014 season.
http://www.viaircorp.com/250C-IG.html
I wanted to hear your guys input especially if I missed something in the rules.
Because it looks like far superior compressor comparing to VIAIR 90C while still under FRC's 1.05 CFM limitation.

[Mk.32]

Yep it's legal (the 12v version), we used it and loved it! It is heavyyyy so we can it off board.

[ArtemusMaximus]

Thanks Mk.32 for quick reply. It's good to have a confirmation.
Before we found it, I started to work on a heat sink design for 90C cause it was getting very hot even with small fan. I probably better finish design, share it and may be someone would benefit from it.

[theawesome1730]

It is a fantastic piece of hardware. Never even got too hot to touch. It's hefty, but if you need the air, it's worth it. We were asked by probably 10 teams about it and many seem very interested. If you can afford the weight costs, by all means get it. We won't be using the others ever again unless we are too close on weight or don't have many pneumatics. We were a little worried about current draw, but it's no worse than the 90c. Be aware that Q&A said that it is required to use the stainless steel braid leader line and you need to design for that since it is heavy and cumbersome.

[ArtemusMaximus]

Thanks, good to know.
Q&A you are referring to, is it Q325?

[theawesome1730]

Originally Posted by ArtemusMaximus

Q&A you are referring to, is it Q325?

Yes, that's the one, bit of a bummer since it weighs so much and is hard to deal with

[ArtemusMaximus]

I compiled comparison table of compressors I found meet the FRC requirements. I hope it may help someone

[ArtemusMaximus]

And here is heat sink design I was working on.

[Nick1912]

I believe his is another FIRST approved compressor which I was told 254 used this year and with 17 pistons it probably got a good workout (someone may want to check me on both of those). It is only a little heavier than the KOP compressor too http://www.gd-thomas.com/product.aspx?id=12622&tp=p

[wilsonmw04]

Originally Posted by Nick1912

I believe his is another FIRST approved compressor which I was told 254 used this year and with 17 pistons it probably got a good workout (someone may want to check me on both of those). It is only a little heavier than the KOP compressor too http://www.gd-thomas.com/product.aspx?id=12622&tp=p

we used this to good use.

[ArtemusMaximus]

Originally Posted by Nick1912

I believe his is another FIRST approved compressor which I was told 254 used this year and with 17 pistons it probably got a good workout (someone may want to check me on both of those). It is only a little heavier than the KOP compressor too http://www.gd-thomas.com/product.aspx?id=12622&tp=p

Oh yes, thank you.
I saw that one but was too lazy to add it to the list. It seemed not much better, yet quite a bit more money.
On the other hand it still viable option and will add to the list.

[kmusa]

Originally Posted by ArtemusMaximus

And here is heat sink design I was working on. ...

Mounting fins to the motor case may work, but most of the heat is being generated in the cylinder, and not in the motor (Viair, for instance, specifically mentions not mounting the compressor upside down, because they find that more heat transfers from the cylinder to the motor.)

What we found is that just having a fan blow on the cylinder head kept the compressor temperature reasonable.

-Karlis

[ArtemusMaximus]

Originally Posted by kmusa

Mounting fins to the motor case may work, but most of the heat is being generated in the cylinder, and not in the motor (Viair, for instance, specifically mentions not mounting the compressor upside down, because they find that more heat transfers from the cylinder to the motor.)

What we found is that just having a fan blow on the cylinder head kept the compressor temperature reasonable.

-Karlis

We also had fan blowing at the cylinder head. However we also found that our compressor was so overworked that motor was very hot as well. May be not hot enough to cause 1st degree burns, but I wasn't dumb enough to test that .
One of the reason for extra working time probably due to a minor pressure loss that we were unable to locate. I soped the heck out of it and didn't see any bubbles

As I looked at the design I posted it occurred to me that it is perhaps an overkill. I will put more thought to it and if I can make it simpler while still effective.

[cbale2000]

While we're on the topic of compressor cooling, here's a chart I made a few years back detailing the temperature difference a cooling fan makes on a VIAIR 90C air compressor...

https://docs.google.com/spreadsheet/ccc?key=0AqQx991m_YKGdEc3OV9NbG10YmluNjM2UFRhYV9Gb lE&usp=sharing

Hopefully someone finds this useful.

[yash101]

Originally Posted by ArtemusMaximus

And here is heat sink design I was working on.

It is not the motor of the compressor that gets way too hot. The pump portion of the compressor is where the heat actually is generated, because you are concentrating the kinetic energy of air into a much smaller volume when you compress it. This causes a ton of heat to be expelled. To make the heat sink design more efficient, it would be wise to focus it's efforts on the small appendage that sticks out the end of the motor.

The reason why it seems as the motor gets quite hot is because the entire body is metal, so it conducts heat well. A ton of heat is generated at the actual compressor, making it extremely concentrated. Entropy finds conduction as one of the easiest way to spread out the heat, so it heats up the motor, which runs quite cool at that load.

If you were to build that heat sink, it would add more weight than benefit. The compressors shouldn't create so much heat within the two minutes of the game, that you would need to cool them with more than a small fan, even under a ~100% duty cycle!