Modifying 40 Amp maxi fuse block

[kborer22]

i was looking at some threads from last yr and from what they said you could use the Big Cim on a 30A if you wanted. And in the wiring diagram they have the FP motors going to the 20/30 A panel. But regardless....we would rather use the 40A...does anyone know the rule about modifying the maxi block?

[chris31]

Originally Posted by kborer22

i was looking at some threads from last yr and from what they said you could use the Big Cim on a 30A if you wanted. And in the wiring diagram they have the FP motors going to the 20/30 A panel. But regardless....we would rather use the 40A...does anyone know the rule about modifying the maxi block?

By "modifying", do you mean something like "cutting in half"?

Ill have to check but I dont think you can modify any of the electronics.

[kborer22]

if yoru farmilar with the block.....one end is solid and the other ends and individual clips, we removed the big block and now have 2 individual clips....

[Kevin Sevcik]

I'll go ahead and guarantee you that this will be illegal, even if it doesn't appear to be now. The breaker panel is designed to be safe in its original configuration. cutting it in half will be viewed as rendering it unsafe, and the part will be declared illegal. FIRST is pretty serious about keeping teams from accidentally attempting arc welding with a poorly wired robot.

[Price Vetter]

Even though it is a FP motor it is also concidered a CIM motor and therefore must use a 40AMP breaker.
Although there may be no rule specifying that you can't modify the breakers it's more than likely illegal.

[Kevin Sevcik]

Adam and Price,

A. He's asking if he can modify the Maxi panel, not if he can protect a Bike Motor with a 30 A.

B. You're wrong. You can protect a speed controller with whatever breaker you like, and you can then use that speed controller to power whatever motor you want.

<R97> Speed controllers may be protected by 20A, 30A, or 40A circuit breakers. Speed controllers may power motors or devices of any size.

Doesn't get any clearer than that.

[Richard Wallace]

Thanks, Kevin; I agree that is perfectly clear.

Back to the original question:

<R46> prohibits "Fuse panels different from those provided in the Kit Of Parts." Modifying the maxi block would render it different, so you can't do that.

[Price Vetter]

B. You're wrong. You can protect a speed controller with whatever breaker you like, and you can then use that speed controller to power whatever motor you want.

Right...but you still cannot power any CIM motor through any thing less than a 40A Breaker...correct?

[Kevin Sevcik]

Originally Posted by Price Vetter

Right...but you still cannot power any CIM motor through any thing less than a 40A Breaker...correct?

Read <R97> again. You can protect a speed controller with any breaker. Say 20A. You can then hook up whatever motor you like to this speed controller that's protected with a 20A breaker. Even a CIM. This may not be intelligent in any given situation, but I've seen a lot of legal, unintelligent things on robots.

Richard,

Thanks, I figured there was a rule that applied directly, but couldn't pick the right one out of so many options.

[steveg]

kb isn't really clearly describing what's being proposed.

If you look at the Maxi panel, the big brass pieces are attached to the plastic with little screws. We're wondering if it would be legal to remove the unused brass, not cut, nodify or otherwise destroy the breaker panel. No parts will be damaged, and everything on there will be original, it would just be without a few pieces of brass. There's no inherent reason why doing this would be unsafe, and we're not doing anything that anyone with a phillips head screwdriver couldn't do.

[Kevin Sevcik]

If it came with the brass, and you have you unscrew things to remove it, you're modifying the part and it's not the original anymore. I completely sympathize with the notion, and 57 is looking at powering some FP motors with 30A breakers just to avoid this same problem. It just doesn't look legal from reading the rules this year and experience from years past. You're more than welcome to ask on the Q&A, however.

[Rosiebotboss]

Originally Posted by steveg

kb isn't really clearly describing what's being proposed.

If you look at the Maxi panel, the big brass pieces are attached to the plastic with little screws. We're wondering if it would be legal to remove the unused brass, not cut, nodify or otherwise destroy the breaker panel. No parts will be damaged, and everything on there will be original, it would just be without a few pieces of brass. There's no inherent reason why doing this would be unsafe, and we're not doing anything that anyone with a phillips head screwdriver couldn't do.

Steve,

If I were your Robot Inspector, and I may be, I would render the modified Maxi block illegal. You may appeal my decision to the Lead Inspector, to FIRST, to the Supreme Court, but why take a chance. Make your weight savings in some other area.

[kborer22]

yea we have not cut anything, merely reconfigured they set up that it was originally in. On one side there is a single input to come from the new dist block they gave us(the one that slides along that track), and on the other side there are 4 individual clips to hold the other end of the 40A breaker with 4 single outputs to go to each victor. We simply took off the single input block(which shorts together all 4 of the breakers) and using all the original hardware moved another single out put to the input side....


btw....you are allowed to use 30A on cims but depending using a smaller breaker will decrease the amount of torque you get out of motor.

[Al Skierkiewicz]

Steven,
It was legal in the past to remove the unused portions of the Maxi Fuse block to save weight. This question has not been asked or answered this year to my knowledge. Keep checking the Q&A or make sure you post this question. In any case, the block must be protected with the clear plastic cover that shiped with the block for insulation purposes.

As many have pointed out, it is within the rules to use smaller breakers and smaller guage wire if a team chooses. The breakers are sized to appropriately protect the wire guage as specified. (for those of you who will look this up and find discrepancies, remember you can derate the safety margins since the wiring is in the open air and you only have a few minutes of "ON" time) So you can make the changes but WHY??? By moving to #12 wire from #10 and downsizing the breaker you provide a 50% increase in series resistance and further limit the power of the motor. By moving down to a 20 amp breaker and #14, you may have a hard time starting a motor under load. The FP and CIM motors are capable of 100 amp stall currents, all you will be doing is tripping the breakers which make them hot and cause them to trip more often. I can hear some of you saying 'but I am designing the system to not stall the motors'. The definition of a stalled motor is one which is not turning, therefore every motor is in stall when it starts.
The buzzing you here is the breakers rapidly tripping and resetting.

[kborer22]

yes thats exactly what we did was just remove the extra stuff were not using....thanks