Neo 550 Wiring

I noticed today that the NEO 550 has 16 AWG wiring coming out of it (see NEO 550 Brushless Motor - REV Robotics ). I also noticed that rule R622 seems to say that if you are using 16 AWG wiring, you must use at most a 20 amp breaker.

I don’t think there is any reasonable or legal way to replace that wiring, and even if you extended the wires with something thicker, presumably the rule is referring to the thinnest part of the wire. So all of this seems to suggest that the biggest breaker you can use on a NEO 550 is 20 amp.

I think there’s a decent chance that we inadvertently broke this rule in 2020, and I wouldn’t be surprised if others did as well.

Am I thinking about this correctly?

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R622 also includes the statement: “Wires that are recommended by the device manufacturer or originally attached to legal devices are considered part of the device and by default legal. Such wires are exempt from this rule.” If you are extending these wires, you might want to stick to the listed sizes however. I don’t think like-extensions would necessarily fall under the same exemption, at least with the current wording.

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As you’ve noted, R622 makes these wires explicitly legal because they are attached to the device by default. Use a larger wire for the extensions (according to the minimum size for the breaker).

The wires are legal as they are part of a legal device. It is important to note the NEO 550 must be controlled by a spark max controller and the wires from the power distribution to the motor controller must follow the breaker rules. The motor phase wires are also not receiving current the same way as the spark max (trapezoidal commutation) so it’s not as easy to compare.

I will say however that a 40A breaker is surely overkill for a NEO 550 as the motor will most likely burn up before a 40A breaker pops. (We always try to stick with 20A current limit on our 550s so they can stall indefinitely* without burning up)

*In a match amount of time

Thanks. Your point about the motor burning up before the breaker pops is generally true, but not in all circumstances. Consider a use case where you only need to run the motor for a few seconds, but at 60 amps. According to this, the motor will run fine for 6 seconds before it starts to fail:

https://www.revrobotics.com/neo-550-brushless-motor-locked-rotor-testing/

But, looking at the breaker data sheets, a 20 amp breaker could trip in as quickly as 1 second at 60 amps:

Whereas a 40 amp breaker wouldn’t trip until at least 15 seconds.

So, if your use case is that you want to run the motor for an amount of time between 1 and 6 seconds, at 60A (which happens to be what our use case is), being able to use a 40 amp breaker makes it a lot more feasible than a 20 amp breaker.

Also, thank you to everyone for pointing out the text in this rule which explicitly allows this. I can’t believe that I missed that!

Per Q and A question 91:

Use of a particular wire gauge in a device is considered a recommendation to use that gauge wire when connecting the device to a circuit

Interesting that it is being ruled legal. Makes sense though. I’ll repost my answer here because I think that it is still a best practice (for motors or any other high-draw devices).

“Use a larger wire for the extensions (according to the minimum size for the breaker).”

We are planning to use 15amp fuses for our NEO 550’s, being that we are going with lower draw can 2 of these be run off the Rev Mini Power Module? I don’t see any rules on this in the 2023 Game Manual.

No, as per R621 you can only have one motor controller plugged into each slot on the PDH/PDB.

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Yeah, if you run them via the mini power module they are still each on their own fuse.

No, they aren’t. Where is the Mini Power Module getting its power?

Right. One slot of the PDP/PDH. By rule, you can only have one motor per breaker on said PDP/PDH.

They’re all on one slot, you end up rewiring at competition. Unless the Q&A someone submitted asking the same question ends up causing a rule change.

I appreciate all of the quick replies and I like the suggestion to submit the question. I will let you know when I get a response!

Same answer that was already given, just official this time.

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