Al's Annual Inspection Thread 2015

[JamesCH95]

Originally Posted by rich2202

I think "installed" is the key word. R65 says the original condition. "optional" parts are not part of the original condition.

Now, if it came with it installed, then the question is whether R65-C applies since you would be "disassembling" to remove the NPT fitting, and not "assembling".

Bingo.

[MrForbes]

Originally Posted by scca229

Just to verify:

PDB <-> 40A Breaker <-> 12AWG wire <-> Victor <-> 14AWG wire directly attached to CIM

Legal?

As I understand it, this is legal. You can also add a length of 12 AWG wire between the Victor and the 14 AWG wire.

[Al Skierkiewicz]

So let me cover both issues here, starting with the wire.
CIM motors have a slightly higher temperature insulation and in practice would be wired to a long length of wire. (They were originally designed for trailer tongue positioners as I remember.) In our application, you can run #10 to them if you so desire. The short length of higher temp wire still keeps them safe for our purposes.
The output port of the compressor is supplied with a check valve to prevent system pressure from bleeding through the compressor. I haven't examined one in a while so I don't remember if that fitting is part of the check valve. I will try and check tonight before we mount the compressor (maybe).

[JamesCH95]

Originally Posted by Al Skierkiewicz

So let me cover both issues here, starting with the wire.
CIM motors have a slightly higher temperature insulation and in practice would be wired to a long length of wire. (They were originally designed for trailer tongue positioners as I remember.) In our application, you can run #10 to them if you so desire. The short length of higher temp wire still keeps them safe for our purposes.
The output port of the compressor is supplied with a check valve to prevent system pressure from bleeding through the compressor. I haven't examined one in a while so I don't remember if that fitting is part of the check valve. I will try and check tonight before we mount the compressor (maybe).

Thanks!

[Jon Stratis]

I know one of their different compressors, the 250c IG variant utilizes a completely separate check valve that has to be installed to work.

[FrankJ]

Originally Posted by MrBasse

I might be missing something really simple, but I never understood this rule. If the device in question has 14 AWG wire standard, why do I have to feed it with 12 AWG? Are we trying to say that the manufacturer is not using the proper wire? A CIM on a 40 AMP breaker will draw a good amount of current if you tell it to, but why doesn't the CIM wiring dictate what wire is used between the breaker and the speed control?

How does it make sense that I would have to crimp 12 AWG wire to 14 AWG wire after the speed controller to be legal? How does that help?

Just be really happy First doesn't make you take apart the motor and solder 12 AWG wires to it. In the integral HP world, the feed wires are always bigger than the wires in the motor. The manufacturer can make an engineering judgment on how big the wires need to be based on more known factors than the general case of power distribution wiring.

[Mr V]

Circuit breakers are circuit protection devices, that means they exist to protect the wire. What they protect the wire from is the insulation getting so hot it melts. There are many types of insulation with many different melting points and the rating for the wire and insulation is dependent on the conditions it is used in. That means there is no universal rating for say a 12ga wire. The CIM wires enter the motor where the temps will be much higher than ambient. Because of that they use high temp insulation which means that particular 14ga wire can safely carry a 40a load.

It is not practical for all inspectors to be trained to identify all types of insulation, know their temp ratings and to have to check the type of insulation on a robot by robot basis. So FIRST makes the assumption that a motor MFG knows what they are doing when they selected the attached wire and that the average team will be using wire with low temp insulation and set the rules accordingly.

[Wayne Doenges]

Several other things that get missed when building our bots.
1) Please allow easy access to the 120 amp breaker. No one wants to see their bot burn because the ref couldn't find the breaker.
2) The same for the pneumatic vent. Don't hide it.
3) Sharp corners. I don't like to see blood, espaeiclly my own
4) If you are using pneumatics, please have the guages where we can see them.

[Al Skierkiewicz]

James,
I checked our ViAir last night and the check valve is mounted directly to the compressor. It has a nice arrow punched into the body. The additional fitting appears to the transition for supplied check valve. I did not pull ours apart to see what, or if, there is a threaded transition on the check valve. This is certainly a question for the Q&A I think. I like that there is some metal at that port to help cool off the output air. That little compressor does run hot if you run it often.

[Richard Wallace]

Originally Posted by Jon Stratis

I know one of their different compressors, the 250c IG variant utilizes a completely separate check valve that has to be installed to work.

I see that your team has asked the GDC (Q360) if the check valve supplied with Viair model 250C-IG compressor is legal.

If that check valve is considered a part of the compressor, then NOT using it would violate R65. If it is considered a separate part, then using it would violate R66.

Based on the GDC's response to 2014 Q325, I think the hose AND the check valve that come from the manufacturer should be considered parts of the compressor, and therefore required per R65. Of course my opinion is worthless at inspection.

Eagerly awaiting the GDC's word on 2015 Q360.

[Jon Stratis]

Originally Posted by Richard Wallace

I see that your team has asked the GDC (Q360) if the check valve supplied with Viair model 250C-IG compressor is legal.

If that check valve is considered a part of the compressor, then NOT using it would violate R65. If it is considered a separate part, then using it would violate R66.

Based on the GDC's response to 2014 Q325, I think the hose AND the check valve that come from the manufacturer should be considered parts of the compressor, and therefore required per R65. Of course my opinion is worthless at inspection.

Eagerly awaiting the GDC's word on 2015 Q360.

Yup, that was me asking... I saw them answer a question that check valves are illegal (which was expected), but wanted to make sure there was another answer directly applicable to the compressor we're using so an overzealous inspector didn't point to that Q&A and make our whole system worthless. I can't overturn inspectors when dealing with my own team

[FrankJ]

Originally Posted by Jon Stratis

I know one of their different compressors, the 250c IG variant utilizes a completely separate check valve that has to be installed to work.

All the First legal compressors have two check valves in them. One on the inlet, one on the outlet. Without them, the compressor essentially becomes a cylinder mounted to a motor.

[JamesCH95]

Originally Posted by Al Skierkiewicz

James,
I checked our ViAir last night and the check valve is mounted directly to the compressor. It has a nice arrow punched into the body. The additional fitting appears to the transition for supplied check valve. I did not pull ours apart to see what, or if, there is a threaded transition on the check valve. This is certainly a question for the Q&A I think. I like that there is some metal at that port to help cool off the output air. That little compressor does run hot if you run it often.

Thanks Al, will submit a Q&A.

FWIW we have mounted numerous 'hard' brass fittings to the compressor outlet to aid in cooling off the compressed air.

Edit: Q&A here - https://frc-qa.usfirst.org/Question/...fitting-remain

[Jon Stratis]

Originally Posted by FrankJ

All the First legal compressors have two check valves in them. One on the inlet, one on the outlet. Without them, the compressor essentially becomes a cylinder mounted to a motor.

Right, check valves are pretty necessary for a compressor, but most of them have it "built in". The 250C IG has it attached to the required leader hose, and it's real easy for it to be viewed by an inspector as a separate part.

[FrankJ]

Originally Posted by Jon Stratis

Right, check valves are pretty necessary for a compressor, but most of them have it "built in". The 250C IG has it attached to the required leader hose, and it's real easy for it to be viewed by an inspector as a separate part.

I understand.

From a functionality point of view he check valve needs to be attached directly to the compressor to keep the compression ratio as high as possible. The braided hose there to keep people from attaching plastic hose directly to the compressor which can be hot enough to cause the plastic hose to fail.