[InFlight]

Originally Posted by jvriezen

There is a safety concern in using two connectors. In normal motor circuits, if a wire comes lose, current stops flowing (until the loose wire shorts to the other side of the circuit and trips the breaker). If a connection breaks loose to one of the slip ring connectors, you now have 40A going through the 30A remaining ring -- and things start to heat up -- the slip ring conductor is your breaker, and not a very good one

I'd think that overloading a circuit due to losing half the conductor might have more danger than the lower risk of suddenly shorting something and blowing a breaker immediately.

Disclaimer: I am not an electrical engineer nor an electrician. I occasionally play one on CD. And when inspecting robots, sort of...

The specified current carrying capability of wires is highly derated vs. their actual capability at room temperature conditions. (Likely 2x or more). The National Electric Code is very conservative, and it permits parallel power feeds.

The CIM motor is wound with magnet wire that is a very small fraction of the circular mills of either a 30 or 40 amp wire. The internal brush connections are not that large either. If you provided a constant 40+ amp load to a CIM motor with 30 amp wiring, the CIM motor would in all likelihood be the first source of failure. It simply can't reject the heat fast enough.