Electrical solenoids

[Smaug]

are they permitted? if not does any one know why it is not permitted?

[Qbranch]

<R46> (page 18) (http://www.usfirst.org/uploadedFiles/Community/FRC/FRC_Documents_and_Updates/2007_assets/Manual/8-The_Robot,Rev%20G.pdf) Directly states no electrical solenoid actuators. If i had to guess, i'd say there is a danger of fire from misuse of intermittent-duty (or continuous duty) solenoids.

-q

[dtengineering]

To agree with Qbranch and expand, I think some rules that appear to be overly strict are there so that they are simple to enforce.

For instance by saying "No solenoids", a tech inspector does not have to be an expert on solenoids to determine whether or not they are being used safely. By limiting the pneumatics components, the tech inspectors can easily identify legal parts. They don't need to refer to a catalog to determine safe operating limits for a hundred different types of cylinder. By saying "No Tape", the tech inspector doesn't have to get into an argument over whether the tape is ugly, or unsafe, or poor practice... it's tape, it's gone.

You see this with the safety glasses rule at competitions... is it overkill? Darn straight, but it is pretty difficult to misinterpret it, isn't it? Simple is good, sometimes.

This is, I believe, similar reasoning to why you can't take nail clippers on an airplane... it seems a bit silly, but it saves the security guards from having to get into a discussion over what is and what isn't a "safe" nail clipper. Simple. Fast. Efficient. For the officials, if not for you.

Just my $.0208 CDN

Jason

($.0208 CDN = $.02 US... I'm hoping for parity before we have to pay the entry fees....)

[Otaku]

To agree with Qbranch and expand, I think some rules that appear to be overly strict are there so that they are simple to enforce.

For instance by saying "No solenoids", a tech inspector does not have to be an expert on solenoids to determine whether or not they are being used safely. By limiting the pneumatics components, the tech inspectors can easily identify legal parts. They don't need to refer to a catalog to determine safe operating limits for a hundred different types of cylinder. By saying "No Tape", the tech inspector doesn't have to get into an argument over whether the tape is ugly, or unsafe, or poor practice... it's tape, it's gone.

You see this with the safety glasses rule at competitions... is it overkill? Darn straight, but it is pretty difficult to misinterpret it, isn't it? Simple is good, sometimes.

This is, I believe, similar reasoning to why you can't take nail clippers on an airplane... it seems a bit silly, but it saves the security guards from having to get into a discussion over what is and what isn't a "safe" nail clipper. Simple. Fast. Efficient. For the officials, if not for you.

Just my $.0208 CDN

Jason

($.0208 CDN = $.02 US... I'm hoping for parity before we have to pay the entry fees....)


This is a logical post.

If I were an inspector I wouldn't want to memorize what types of things are alright and what aren't. I would want to know general stuff like the no tape rule.

[Al Skierkiewicz]

As Qbranch has pointed out. R46>"Items specifically PROHIBITED from use on the robot during competition matches include:
Electric solenoid actuators (note: electric solenoid actuators are NOT the same at pneumatic solenoid valves – the latter are permitted, the former are not)."


This is one of those rules that even I don't understand. I am hoping that one day we will be able to use solenoids. They (solenoids) would make it possible for teams that only want to shift their transmissions to do so without the need to add pnuematics to their robots. I would think that a little cooperation with AndyMark ought to allow an electrically shifted transmission. Eventually the use of a solenoid to lock a turret in place or some other function would be nice as well.

[Qbranch]

Actually... to agree and expand on both what DTengineering and Al have said... perhaps ther is a solution for future FIRST years to allow solenoids.

Solenoids arent dangerous really except for if they get hot and catch fire (as i said). So, maybe FIRST can require safety equipment be installed in/with each solenoid before it is used kind of like how FIRST requires fuses, or AllenBradley lights, or whatever.

What if FIRST just required that teams put a specifically specified Temperature acting snap action switch be put in series with the solenoid, and that it be attached to the solenoid in a specifically defined manner. (Like this one. (http://www.thermodisc.com/productdetail.asp?ProductID=2)). Or, maybe FIRST can have KOP solenoids made that incorporate a thermocouple or something like that switch i listed above.

Anyways, with heavy regulation on which solenoids can be used, or a special KOP solenoid with temperature sense (or just one of the bimetal overtemp switches) could make using solenoids safe.

Are there other safety risks i'm overlooking? Is this too complicated? Too hard to enforce? What are your thoughts? (bell rang, gotta go...)

-q

[Al Skierkiewicz]

Alex/Q,
There isn't a safety issue in my mind with solenoids. The wiring rules would still cover them, i.e. 20 amp breaker feeding the solenoid through a Spike fused at 20 amps. The danger of fire from misuse of a 12 volt solenoid during a two minute match is not an issue.

[Smaug]

yeah thank you every one for your input. the reason we wanted to use solenoids is it would make our ramp deploying mechanism very simple and efficient.

[Al Skierkiewicz]

yeah thank you every one for your input. the reason we wanted to use solenoids is it would make our ramp deploying mechanism very simple and efficient.

Smaug,
We didn't say they were legal just that we disagree with the rule. In some cases, a servo does an excellent job at imitating a solenoid.

[Otaku]

he didn't say we were going to use one. He was just asking because he wanted to.

[Smaug]

yeah what otaku said i guess i should be a little more specific with what i say

[Al Skierkiewicz]

That's OK. I do come across teams that hope to use some device or another and are expecting the answer to be yes. Just making sure is better than telling you to take it off during inspections.