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-   -   compressor is heating up to the point it blows hose (http://www.chiefdelphi.com/forums/showthread.php?t=136117)

MrForbes 26-03-2015 00:13

Re: compressor is heating up to the point it blows hose
 
Mount one of the little kop fans on a bracket on the robot , so it blows on the compressor fins . Do not mount it to the compressor. Power the fan with a 20 amp breaker from the PDP. this is all you need to do to keep the compressor cool.

benherms 26-03-2015 10:43

Re: compressor is heating up to the point it blows hose
 
If you plan to use the standard ~9% Duty Cycle compressor, use one of the previous-gen Victor fans as we (Team 195) did this year, or any standard electronics cooling fan. Point it directly at the heatsync but do not mount it to the compressor for fear of violating "No-modification" rules.

Ether 26-03-2015 10:51

Re: compressor is heating up to the point it blows hose
 
Quote:

Originally Posted by benherms (Post 1462371)
or any standard electronics cooling fan

? Legal



JamesCH95 26-03-2015 11:09

Re: compressor is heating up to the point it blows hose
 
Quote:

Originally Posted by MrForbes (Post 1462308)
Mount one of the little kop fans on a bracket on the robot , so it blows on the compressor fins . Do not mount it to the compressor. Power the fan with a 20 amp breaker from the PDP. this is all you need to do to keep the compressor cool.

x2

This has worked very well for us for several years, especially when combined with mounting all of the metal fittings directly to the compressor.

Nate Laverdure 26-03-2015 11:13

Re: compressor is heating up to the point it blows hose
 
Quote:

Originally Posted by Ether (Post 1462375)
Quote:

Originally Posted by benherms (Post 1462371)
or any standard electronics cooling fan

? Legal

I am guessing that Ether wants us to remember that <R18> limits us to fans that were included in the 2015 KOP or FIRST Choice.

I am convinced that using a 40mm fan to blow air across the head of a VIAIR 90C is the best configuration for 99% of all FRC applications. Just amazing performance.

vhcook 26-03-2015 13:01

Re: compressor is heating up to the point it blows hose
 
Quote:

Originally Posted by tickspe15 (Post 1462235)
We use a different type of tube coming off the compressor that is rated for higher temperature operation. I believe the tube we use is rated for 200+ degrees Fahrenheit compared to the KOP tubing which is rated for 120ish degrees. We have also experimented with a metal sheathed tube coming off the compressor but higher rated tube seems to work just as well and be much lighter.

Could you provide a part number/source for this high-temperature-rated tube?

Mschmeh144 26-03-2015 13:56

Re: compressor is heating up to the point it blows hose
 
the fan idea works great. our 2013 bot has the compressor overheating problem, but after my overhaul on all the bots, I added a small fan mounted above it blowing down on it and it keeps it very cool. haven't had a air leak since.

ArtemusMaximus 26-03-2015 15:03

Re: compressor is heating up to the point it blows hose
 
Quote:

Originally Posted by Dunngeon (Post 1462233)
Are you running the VIAIR 90 C? We too had this issue, for the practice bot we switched the compressor to a Thomas 215 which is rated for 100% duty. We retained the 90C for the competition bot because it only needs to run in short bursts.

Correction: Thomas 215 may be better in some regards but it definitely is not rated 100%, it's actually rated only @10%/100psi (Link)

Check this last year thread
http://www.chiefdelphi.com/forums/sh...d.php?t=129321

To my knowledge only these 3 compressors are 100% duty and FRC legal (at least according to 2014 rules)
  • Thomas 405ADC38/12
  • Thomas 415CDC30/12
  • Viair 250C-IG

See comparison list I compiled last year http://www.chiefdelphi.com/forums/at...1&d=1399302557

rich2202 26-03-2015 15:27

Re: compressor is heating up to the point it blows hose
 
When they say "10% Duty Cycle", over what period of time is the 10%? 2.5 minutes on (for a match), and 22 minutes off?

Jaxom 26-03-2015 15:45

Re: compressor is heating up to the point it blows hose
 
Quote:

Originally Posted by tickspe15 (Post 1462235)
We use a different type of tube coming off the compressor that is rated for higher temperature operation. I believe the tube we use is rated for 200+ degrees Fahrenheit compared to the KOP tubing which is rated for 120ish degrees. We have also experimented with a metal sheathed tube coming off the compressor but higher rated tube seems to work just as well and be much lighter.

Don't forget that the pressure relief valve (calibrated to 125 psi or lower) must be connected to the compressor via hard fittings (R67.B, R76). If your compressor only has one port you're going to have at least one tee on it; might as well make it brass and get some heat sink value.

ArtemusMaximus 26-03-2015 15:48

Re: compressor is heating up to the point it blows hose
 
Quote:

Originally Posted by rich2202 (Post 1462425)
When they say "10% Duty Cycle", over what period of time is the 10%? 2.5 minutes on (for a match), and 22 minutes off?

Compressor doesn't just work 2.5 minutes on the field. I don't know any team that would let their bot to go on the field with empty stomach .. uh .... I mean empty air tanks. Then it has to work during match. Times between matches are sometimes less than 20-30 minutes. Some of the times is used to adjust bot system and running tests, meaning more compressor usage. No wonder that number of teams have compressor overheating issues.

You cannot call it 100% duty cycle. Besides being incorrect, it is very misleading.

Comparing apples to apples, Viair 90C is 9% Duty cycle, just 1% less than Thomas 215. Which means that difference is marginal.

Having even small fan cooling off compressor will make more impact than switching from Viair 90C to Thomas 215. Especially considering that Thomas 215 is 3 times more expensive that Viair 90C. If you can spare 4 pounds on you robot Viair 250C-IG is much better choice for less money.

AdamHeard 26-03-2015 16:01

Re: compressor is heating up to the point it blows hose
 
Quote:

Originally Posted by ArtemusMaximus (Post 1462431)
Compressor doesn't just work 2.5 minutes on the field. I don't know any team that would let their bot to go on the field with empty stomach .. uh .... I mean empty air tanks. Then it has to work during match. Times between matches are sometimes less than 20-30 minutes. Some of the times is used to adjust bot system and running tests, meaning more compressor usage. No wonder that number of teams have compressor overheating issues.

You cannot call it 100% duty cycle. Besides being incorrect, it is very misleading.

Comparing apples to apples, Viair 90C is 9% Duty cycle, just 1% less than Thomas 215. Which means that difference is marginal.

Having even small fan cooling off compressor will make more impact than switching from Viair 90C to Thomas 215. Especially considering that Thomas 215 is 3 times more expensive that Viair 90C. If you can spare 4 pounds on you robot Viair 250C-IG is much better choice for less money.

Eh, I'm not sure I trust Vair specs NEARLY as much as Thomas specs.

Mr V 26-03-2015 16:31

Re: compressor is heating up to the point it blows hose
 
Quote:

Originally Posted by rich2202 (Post 1462425)
When they say "10% Duty Cycle", over what period of time is the 10%? 2.5 minutes on (for a match), and 22 minutes off?

I don't know what the maximum on time is for the Thomas but somewhere I saw that the Viar was rated for a max on time of 3min. So a ~30 sec initial charge time, a few minutes of rest, 2.5 minutes of cycling on and off during the match and ~30 minutes between matches puts it in its intended duty cycle.

Quote:

Originally Posted by AdamHeard (Post 1462432)
Eh, I'm not sure I trust Vair specs NEARLY as much as Thomas specs.

Personally the fact that Viair rates theirs at 9% makes me trust their specs more and the fact that Thomas rates theirs at 10% makes me suspicious of their specs. Fact is that real world numbers rarely come out so nice so Viair advertising 9% makes me think it is based on actual data determined by real world testing w/o rounding it up to 10% which would look better on the data sheet.

Team3844 26-03-2015 21:28

Re: compressor is heating up to the point it blows hose
 
Moved all of our metal fittings down to the compressor for the heat sink value today. It fixed the problem with the added help of throwing more ballast to the back of the robot.
We did discover one trick that we did last year without knowing how it helped.
We used a plastic elbow push fitting as the first non metal fitting last year. The extra heavier thermoset housing helped isolate some of the heat before it got to the tubing.

Team3844 26-03-2015 21:29

Re: compressor is heating up to the point it blows hose
 
Thanks for all the replys. We learned a lot from going through them with the team.


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