Converting 12v to 24v

[Al Skierkiewicz]

Alan,
A speaker is a solenoid and often it is referred to as such in technical literature. In relation to a what we normally think of as a solenoid, the coil moves in a speaker instead of remaining stationary as in a common solenoid.
As I stated much earlier, a solenoid by definition moves something when an electric current flows. The bell does exactly that.

[FrankJ]

I looked at a few definitions of "solenoid" just now, and the common feature was ..., or moved a coil between permanent magnets.

Sounds like a speaker to me. But speakers would be prohibited under the no noise maker rule?

Read 2012 rule 48. If clutch is operated by a magnetic coil, you should be arguing that it is a solenoid otherwise you cannot use it unless it is powered by an allowed servo or motor.

While I generally do like stretching definitions, what GDC it trying to do is fairly clear. They trying to allow small magnetic actuators and at the same time keep the rules short.

[Johnny_5]

And the GDC has it!

I just got a response from the official Q&A System.

Q. We want to use an electromagnetic clutch on our robot. The clutch is a 24v component. 1)Is it legal to have a power converter to convert 12v to 24v 2) Are electromagnetic clutches a legal component since they use no actuator?
A. 1) Yes, provided all other Robot Rules are met. 2) There are no Rules specifically prohibiting the use of clutch mechanisms on the Robot. However, these devices may not be used if they contain electric motors and/or servos different from, or in addition to, those permitted in the Robot Rules. Simply put: if the device utilizes an electric solenoid to provide mechanical motion for the device, that solenoid must meet the requirements of Rule [R48-J].

The only problem I see is that in order to use a smaller electromagnetic clutch it must be 24v. There is nothing against having a 12v to 24v converter as long as it follows all other robot rules. But R48-J states that solenoid must 10 watts continuous duty at 12v.

[Tristan Lall]

Originally Posted by Al Skierkiewicz

You are going way out on a limb here.
"If the bell or clutch was not a solenoid or motor, then it would not have been prohibited in 2010." The bell is a solenoid and so is the clutch you show. I have worked on a couple of hundred of these air conditioning clutches over the years. The clutch plate is pulled by the magnetic field set up by the electric current. The pull mates a frictional plate with a metallic plate to lock the pulley to the drive shaft of the compressor. If you stick your finger between the plates when you energize the coil it will get pinched.

I don't dispute that it moves as you describe. We only really differ on the definition of a solenoid (and solenoid actuator).

I'm saying that we need to be discerning about what is a solenoid, lest low-quality solenoids like loops of wire be dragged into the discussion (an outcome nobody wants or believes should exist). I'm presuming that the uniformity of the magnetic field within the core is the distinguishing characteristic of a solenoid. Additionally, even in the presence of a pretty good solenoid, I'm asserting that it's not a solenoid actuator unless the device is using the characteristics of a solenoid (rather than an electromagnet in general) to do its work.

That leads to the distinction I described between solenoid actuators, and electromagnetic actuators (a broad class of devices that includes solenoid actuators and motors).

Originally Posted by Al Skierkiewicz

"This is exclusive with respect to motors and solenoid actuators, but not exclusive with respect to actuators that are neither motors nor solenoids." What actuator is neither a solenoid or a motor or a pneumatic part?

According to my contention, the bell, and maybe the clutch.

If you really want to get creative, I guess an electric actuator that is none of those things might take the form of a bimetal strip combined with a resistive heating element. When you raise its temperature, it bends to a specified position.

Actually, as we discussed earlier, [R48] certainly applies to (at least some kinds of) electromagnetic acutators, and certainly does not apply to pneumatic actuators (because if it did, all pneumatics would be illegal, for lack of mention in [R48]). But does it apply to electroresistive actuators? (Or piezoelectric actuators, or static electric actuators, if such things even exist?)

Also, we can't just apply [R48] to all actuators not explicitly permitted elsewhere (like we might be tempted to do, to get around the pneumatic actuator problem). Then purely mechanical actuators (like a flyball governor) would be prohibited. Nobody wants that—and more importantly, it would be a non-obvious and perhaps even unfair restriction to enforce at inspection.

Originally Posted by Al Skierkiewicz

"Though admittedly the rules aren't clear about this, for 2012 there isn't really any reason why any motor couldn't be considered a custom circuit...there's no significant discrepancy between the motor requirements and custom circuit requirements. I doubt this is necessarily what FIRST intended, but at least it doesn't conflict." How can you draw this conclusion from both the motor list that you state is an exclusive list (excludes all motors not on the list) and from the custom circuit rules which prevent any custom circuit from direct control of a motor?

[R47]
Custom circuits shall not directly alter the power pathways between the battery, PD Board, speed controllers, relays, motors, or other elements of the Robot control system (including the power pathways to other sensors or circuits).

So what exactly are you thinking could appear on an FRC robot that is neither a solenoid nor a motor nor a pneumatic part, that would be in your mind, a legal actuator?

That's the rule I had in mind—you can't alter the power pathway between the device and the power source, but you can alter the pathway inside the device.

If "between" was meant to include the device itself, it would be impossible to make custom circuits that draw power from the robot. Normally it's moot, because you can't really alter motors legally.

But there's no actual conflict between the motor/actuator and custom circuit rules that prevents a device from simultaneously satisfying the requirements for both.

I say there's confusion, only because I don't think that's what the GDC intended, and it may be worth asking them "if a device is (or contains) a motor or other electric actuator, does that exclude it from being a custom circuit".