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-   -   Fans from the PCM? (http://www.chiefdelphi.com/forums/showthread.php?t=134422)

JamesCH95 13-02-2015 09:27
Re: Fans from the PCM?
 
Consider the intent of the 'motors must be connected through controllers' rule. It is there to stop mechanisms from moving when the robot is disabled. It is a safety concern and a game-play concern. Is it dangerous or unfair to allow a cooling fan to remain on when the robot is disabled? No, unless you jam your finger into one, then it stings like crazy. Fans used to cool motor controllers stay on when the robot is disabled, I see no intent in the rules that you prevent a fan from cooling a compressor from running while the robot is disabled.

FWIW we used a fan hard-wired to the PDB last year with no comments from any inspectors.

MrForbes 13-02-2015 09:42
Re: Fans from the PCM?
 
We did too. But I get to play inspector this year, too....so I'm looking at the rules a bit differently.

rich2202 13-02-2015 09:55
Re: Fans from the PCM?
 
Question submitted on directly connecting a fan to the PDB.

JamesCH95 13-02-2015 09:58
Re: Fans from the PCM?
 
Quote:
Originally Posted by rich2202 (Post 1443166)
Question submitted on directly connecting a fan to the PDB.
What number? Can you link please?

Hoover 13-02-2015 09:59
Re: Fans from the PCM?
 
Quote:
Originally Posted by JamesCH95 (Post 1443148)
Consider the intent of the 'motors must be connected through controllers' rule. It is there to stop mechanisms from moving when the robot is disabled. It is a safety concern and a game-play concern. Is it dangerous or unfair to allow a cooling fan to remain on when the robot is disabled? No, unless you jam your finger into one, then it stings like crazy. Fans used to cool motor controllers stay on when the robot is disabled, I see no intent in the rules that you prevent a fan from cooling a compressor from running while the robot is disabled.
I can agree with this first hand. That hand got into the fan and broke a blade off the fan. Miraculously my hand was fine, but stung a little. The new fan has heavy duty blades so we put hard nylon grill on both sides. Now it is noisy.

Quote:
FWIW we used a fan hard-wired to the PDB last year with no comments from any inspectors.
Good points above... yet this. Since the fan is noisy I think I will put it on a relay as I had planned. Whatever we do (or don't), we will get the inspector that makes us do it the opposite way we have done it. If yours is opposite us, and you get passed, we will not tell on you. This has been our way for the last few years (and it has indeed happened), we will be ****ed but stoic.

rich2202 13-02-2015 10:03
Re: Fans from the PCM?
 
Quote:
Originally Posted by JamesCH95 (Post 1443168)
What number? Can you link please?
Q367
https://frc-qa.usfirst.org/Question/...tor-controller

FYI: If you go to the Q&A, and hit Search (without changing any of the other fields), the questions will pop up in reverse order (newest questions first).

MrRoboSteve 13-02-2015 10:09
Re: Fans from the PCM?
 
Quote:
Originally Posted by Hoover (Post 1443169)
The new fan has heavy duty blades so we put hard nylon grill on both sides. Now it is noisy.
Is your fan one of the listed fans from R18?

Quote:
Hard drive motors or fans that are included in the 2015 Kickoff Kit, 2015 FIRST Choice, are a part of a legal motor controller (including manufacturer provided accessories), or COTS computing device

JamesCH95 13-02-2015 10:11
Re: Fans from the PCM?
 
Quote:
Originally Posted by rich2202 (Post 1443175)
Q367
https://frc-qa.usfirst.org/Question/...tor-controller

FYI: If you go to the Q&A, and hit Search (without changing any of the other fields), the questions will pop up in reverse order (newest questions first).
Indeed, it is just helpful to have the link to the Q&A in the thread. So, thanks!

MrRoboSteve 13-02-2015 10:20
Re: Fans from the PCM?
 
Also note Q368, which is a more general version of the same question.

Quote:
R18 lists the permitted motors and actuators, but does not prescribe how they are connected to robot's electrical system. R41 lists permitted power regulating devices for actuators (and motors, implied but not stated), but does not require their use. R42 lists permitted interconnections between loads (including actuators and motors) and the power regulating devices, but does not require their use. Under what circumstances are power regulating devices required to connect loads to the robot?

Hoover 13-02-2015 10:22
Re: Fans from the PCM?
 
Quote:
Originally Posted by MrRoboSteve (Post 1443182)
Is your fan one of the listed fans from R18?
We don't know where the 120mm fan came from but we've had it since at least 2012. Even if it isn't from FRC, it would be considered part of a "COTS computing device".

It is an available Commercial Off The Shelf item available to everyone. Similar to this one.

http://www.amazon.com/Cooler-Master-...ords=120mm+fan

I am a cynic so I expect grief for it nevertheless.

MrRoboSteve 13-02-2015 10:26
Re: Fans from the PCM?
 
You should read the answer to Q315 carefully.

MrForbes 13-02-2015 10:30
Re: Fans from the PCM?
 
If it's this one

http://firstchoicebyandymark.com/fc15-117


then it should be legal, since it is available from FIRST Choice 2015.


A fan removed from a COTS computing device is not legal, according to Q&A 315

Jon Stratis 13-02-2015 10:50
Re: Fans from the PCM?
 
Quote:
Originally Posted by Hoover (Post 1443196)
We don't know where the 120mm fan came from but we've had it since at least 2012. Even if it isn't from FRC, it would be considered part of a "COTS computing device".

It is an available Commercial Off The Shelf item available to everyone. Similar to this one.

http://www.amazon.com/Cooler-Master-...ords=120mm+fan

I am a cynic so I expect grief for it nevertheless.
Check page 11 of the 2012 KoP Checklist... Is it that fan? Being on a past year's KoP makes it a legal fan.

MrForbes 13-02-2015 10:54
Re: Fans from the PCM?
 
Quote:
Originally Posted by Jon Stratis (Post 1443228)
Being on a past year's KoP makes it a legal fan.
I don't think so...R18 specifically states it has to be from the 2015 KOP.

MrRoboSteve 13-02-2015 10:56
Re: Fans from the PCM?
 
The fan rules are surprisingly restrictive this year.


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