3520B owners - electrical question

[Jeff Nicol]

This brings up another question. Isn't there a reset/breaker on the inverter/motor/lathe that is supposed to do the same thing? I have tripped the reset button on the PM a number of times, and on the Robust a few times. Mostly from high speed shut offs with high loads/mass, and a few times from just trying to take off too much.
robo hippy

Reed, When all the failsafes fail the next thing is the lathe! Just because the guy did not die when he jumped over niagra falls are you going to do it too? There is always the correct way to do things and the way that works until the house burns down! I chose to be as safe as possible, but that was not always the case. But after a few minor mishaps I have learned my lessons.

IMHO

Jeff

[Richard Madison]

The logic of saying that an "oversize" breaker and appropriate wire size is dangerous is somewhat flawed. If it were true, then all of our typical 15 and 20 amp household circuits that usually run no more than 4 or 5 amps load (couple of light bulbs or a tv set) should be reduced to 10 amp circuits.

[Scott Conners]

The breaker's purpose it to protect the wire itself and any terminations such as receptacles etc. The load should (and in most cases is required by UL/NEC) have it's own overload/overtemp protection. Older equipment many not have it, but modern stuff should.

Running a lower load on a higher power circuit is not any more dangerous. If the equipment requires protection, it should be via an inline fuse or breaker designed for equipment protection at the load itself. There are many factors to be taken into consideration in choosing the type and sizing of a load protection device, and just guessing at what the proper reduced size breaker is may provide a false sense of security. Motors, for example, may have surge currents at startup that are double or even triple (or more) their rated load, depending on type and what they are driving. A breaker sized at the nameplate load may false trip and/or weaken over time from the repeated overloads. A properly sized slow-blow fuse is simpler and more reliable protection than a typical household magnetic breaker for that situation.

It is completely safe to run a smaller breaker on heavier wire, however it is not correct to say that a properly sized breaker is more dangerous.