Additional field coils around motors

[ConKbot of Doom]

I know everyone always wants more power form their motors, and that we aren't supposed to open them up to mess with them, but if you were to wind additional coils around the motor, could you increase the field strength legally?

I was thinking something along the lines of a series wound or shunt wound coil at first, but those are for AC electric motors, and only go in one direction.

However, if you were to have the field coil on its own speed controller, you could vary the strength of the field for when you need it.

This would be considered a custom circuit, so reading R52 from 2005

Inputs to custom circuits may be connected to the following sources:
Branch Circuit breaker outputs
Speed Controller or Relay module outputs
PWM or Relay outputs on the Robot Controller
Switches, Potentiometers, the outputs from Accelerometers, Sensors, and other additional electronics allowed

So it would be legal to have the inputs of this circuit (the power inputs) connected to a Victor, at least as how I see it.
So it would be setup so that once you hit full power on the motors, you start powering up the field coils around the motor to increase the strength of the motors.

Granted it wouldn't be that easy to wind the coil so that it's field matched that of the CIM, and there already is so much power available, and current draw is allready pretty high. Would it be legal, and beneficial to make a setup like this? Maybe as a big red button for when your in a shoving match or something.

[sanddrag]

What about just putting a steel band around it like the fisher price motor has?

[gburlison]

Originally Posted by sanddrag

What about just putting a steel band around it like the fisher price motor has?

So, if we fabricated a motor mount out of a steel band that wrapped around the CIM, the motor might have a slightly higher power output?

[sanddrag]

Originally Posted by gburlison

So, if we fabricated a motor mount out of a steel band that wrapped around the CIM, the motor might have a slightly higher power output?

In a post I'm too lazy to search for right now Joe Johnson said something to the effect of "if you can pick up a large paperclip with a motor, chances are the motor could benefit from an external flux yoke" (I think that's what it is called) "Torque can be increased up to 20% in some cases"

And you'll notice the FP motor has one of these doo-dads and apparantly it serves a very important purpose.

So, I haven't tried it, and I haven't yet learned about magnetic flux and whatnot (I think about 3 weeks away from learning about that in Physics) but it sounds logical and I'd definitely be willing to try it. Does anyone know if you can pick up a paperclip with a CIM?

[KenWittlief]

the effect of increasing the strength of the field is twofold:

1. you will have more torque for a given voltage
2. your top speed will be lower

the reason for #2 is the stronger field will generate a larger counter-EMF, the back voltage that determines the motor top speed.

[Al Skierkiewicz]

Dave is the closest thus far, the motors already have a magnetic structure designed in. Trying to add to that will likely not result in an increase in performance. However, under another rule, solenoids are not allowed. See also the robot allowed parts flowchart.

[Jack Jones]

Originally Posted by Al Skierkiewicz

Dave is the closest thus far, the motors already have a magnetic structure designed in. Trying to add to that will likely not result in an increase in performance. However, under another rule, solenoids are not allowed. See also the robot allowed parts flowchart.

True. But it's not the result, but more the intent that bothers me.

[Al Skierkiewicz]

Originally Posted by Jack Jones

True. But it's not the result, but more the intent that bothers me.

??

[Tristan Lall]

Originally Posted by Al Skierkiewicz

??

I believe that Jack is concerned about the collective state of mind of a team that encourages them to bend the rule in this manner.

I'm not sure that it's unhealthy to try to push the limits, to exploit loopholes and to generally make life a mess for the inspectors and rule-makers. It's occasionally a little frustrating for those officials, but ultimately, it's mostly harmless. If the inspector or rule-maker says "no", it's final, no matter how much effort you put into it; by bending the rules, you take the risk you will find yourself in that situation. (Now, I should point out that decisions to live on the cutting edge should be undertaken with the consent of the team as a whole. If it's a small group within the team that risks the team's success on a dubiously legal enterprise, which is eventually rejected at a competition, all hell might rightly break loose in that team's pit; just leave the inspectors out of it.)

[Al Skierkiewicz]

I think that is important to note that winning teams have won without bending the rules. GP allows you to go ask, investigate and take pictures. Learn from others when you have the chance.

[Dave.Norton]

[quote=Tristan Lall]I'm not sure that it's unhealthy to try to push the limits, to exploit loopholes and to generally make life a mess for the inspectors and rule-makers.QUOTE]

Agreed. Limits are imposed by both man and nature. Understanding those limits and attempting to push past them is the basis of creativity. Railing against them is unproductive, which is to say lets have fun with the ideas.

[KenWittlief]

accepting the limits of nature? Im not too sure about this

many times it wasnt nature, it was our understanding that was flawed.

Several years ago 2.8k modems were the best you could get, because Nyquist said that is the fastest that data can be transmitted on a phoneline with a 3,000 Hz bandwidth

but now we have 56k modems, on those phonelines with the same 3kHz bandwidth

nature folded on that one and gave in. Sometimes it pays to keep railing :^)

also, sometimes when you sit and ponder ways to cheat, you come up with a good idea that is not cheating - unrestricted brainstorming!

[Jack Jones]

Take another look at <R31> - What part of "So that every robot’s maximum power level is the same," don't you understand?

[ConKbot of Doom]

Originally Posted by Jack Jones

Take another look at <R31> - What part of "So that every robot’s maximum power level is the same," don't you understand?

Yes it says that, but looking at it in context it says after that "the motors in the kit may not be modified except as follows" and the purpose of this would be to do that without modifying the motors.

Sanddrag- Yeah it would be pretty easy to do that, but whats the fun in doing something that you know is going to work allready I'm not going to be actually trying this on anything, just thinking about it.

[Mike Betts]

Jon,

I believe that any such an attempt would be violating the spirit and intent of the rules.

Years ago, Woodie and Dean asked us not to be lawyers. I would echo that sentiment.

Regards,

Mike