Is it possible to safely connect European made (for European market) Bosch Induction 2 burner cooktop, 3700w, 220-240v, 50/60Hz in the USA? Cooktop connection diagram comes in 3 wires: brown, blue and green/yellow. Is it safe to connect brown (EU) to black (US), blue (EU) to red (US) and green/yellow (EU) to green (US) or is there a better/safer way to wire it?
Wiring – How to safely connect EU (220-240v) induction cooktop in the USA
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If your wiring analysis is correct and the neutral is fused, this is most certainly atypical. The hot is fused to prevent a ground short from burning out the appliance and is the reason that a grounded neutral or reverse-polarized electrical plug can be dangerous. Fusing the neutral would not prevent this, which is exactly why the breaker tripped instead of the fuse blowing.
As for why it was done this way? Beats me, unless it is an error. Have you considered contacting the manufacturer? It may simply be an oversight in the U.S. wired models.
With another clockwise fan from the same maker, I was able to reverse the direction by interchanging the yellow and black wires as some answers here indicated. The explanation as I understood is that the rewiring changes the winding with which the capacitor is in series and hence the starting direction is inverted.
In 3-phase motors, each of the three stator windings carry a current out of phase with others and the phase difference generates the rotating magnetic field required to cause the motion. With single-phase ones, a phase difference is engineered by splitting the single phase current into two stator windings and putting a capacitor in series with one of the windings so that there's a 90° phase difference between the currents in the two windings. This page on electric motors explains the concept with illuminating animations.
The following figure shows my guess, based on the above information, at the internal wiring of the clockwise spinning fan whose image is posted in the question, for clockwise and anti-clockwise rotations.
A point to note here is that single-phase AC itself produces a changing magnetic field - though a pulsating one, not a rotating one. But this pulsating field can be resolved, as per the double field revolving theory (the link has an excellent video of the workings by the way), into two revolving fields rotating in opposite direction to each other. These two fields produce an equal but opposite torque. On a static rotor, they'll cancel each other out. But an initial rotation makes torque in one direction greater than the other and starts up the fan.
This is what, I believe, happened when the OP switched red and yellow wires on his fan. The result was that the capacitor was in series with both windings => there was no phase difference in the currents in the windings. When he added a slight initial rotation, the fan continued spinning in the nudged direction.
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Best Answer
First, the US, most countries, and now all countries worldwide have harmonized on safety ground being bare, green, or yellow w/ green stripe. So that's easy. Done.
You will need a letter from Bosch either indicating approval by UL (or some other NRTL) or saying something that will satisfy your AHJ (Authority Having Jurisdiction). This will be required for your permitted work to pass inspection. If you do the work unpermitted, then you are likely to have problems at sale time when the buyer's home inspector spots the alien range and asks questions. It will also be needed to defend your fire insurance should an incident arise which seems related. Consequences for unpermitted work can be severe and have been known to blindside DIYers.
I know the paperwork seems like a lot of nonsense, but state law (NEC) and UL are surrogates for the interests of the fire insurer and mortgage lender. It is, after all, called "Underwriters' Laboratories". However your interests are served also by defining a "bright line" standard for which appliances and work are approved. Convoluted, dragged out, subjective lawsuits are expensive for both sides!
The upshot is that shipping electrical appliances across an ocean (unless it's the Indian Ocean) is usually a bad idea.
As far as the cabling, what's in your walls is a correct and modern 10/3 w/ground intended for a high-end home with a 30A circuit for a cooktop OR oven. (it can't power a combo range-oven typically 40-50A). Ovens need neutral for the oven light. Ranges generally don't need it. Euro ranges definitely don't need it. Simply cap it off and leave it for future use.
However I see a 12/2 NM-B "Romex" cable being used as an extension cord. That's right out. a) it's too small for a 30A circuit, b) it's not cordage (which needs to flex, so must be fine stranded wire), and c) the white wire is not marked to indicate its use as a hot. That marking is especially important around novices, because wouldn't it make sense to attach white to white? If you use black-white-green cordage mark the white wire with red phase tape. Boom, it all makes sense!