I ordered an adapter to provide 120 VAC power to a NEMA 14-50, dual-voltage, EVSE and got this mistake: Both NEMA 14-50 socket receivers go to just one NEMA 5-15 pin ... NO POWER Center NEMA 14-50 socket receiver, current return, goes to the other NEMA 5-15 pin Mechanically a good part but electrically, a disaster! Bob Wilson
I think that's what they'd have to do. You can only get 120 VAC from the 5-15. The 14-50 would ordinarily show you 120 VAC from either leg to neutral, and 240 VAC from one leg to the other. Clearly that's not an option here; the 240 VAC just isn't available. But they can make 120 VAC available between neutral and each leg ... it just happens to be the same 120 VAC on each leg ... and nowhere near 50 amps of it.
A NEMA 14-50 normally has two hots on the opposite, flat insertion sockets with 240 VAC. This is how I've found portable EVSEs configured to use, not the 'current return' and one of the two hot socket slots. So lets look at the different EVSE design options: HOT1 and CURRENT RETURN 120 VAC Works if the adapter and the EVSE use the same two pins. But there is another HOT socket insertion slot. Worse, it puts the load on one side of the house split phase input. HOT2 and CURRENT RETURN 120 VAC Works if the adapter and the EVSE use the same two pins. But there is another HOT socket insertion slot. Worse, it puts the load on one side of the house split phase input. HOT1 and HOT2 120 VAC The EVSE can use the same socket pins and the dual voltage electronics works on either 240 VAC or 120 VAC. It also balances the house split phase input. Bob Wilson
Both NEMA 14-50 socket receivers go to just one NEMA 5-15 pin ... NO POWER Center NEMA 14-50 socket receiver, current return, goes to the other NEMA 5-15 pin Mechanically a good part but electrically, a disaster! I'm confused. Bear with me while I write this out to keep it straight in my head. There's a 5-15 standard household power outlet. One ground (D shaped), one grounded neutral (long flat) and one hot (short flat). 120vac available between the Grounded Neutral and Hot flats Then a 14-50, which has a ground (D shaped), a grounded neutral (center flat) and two hots (outer flats). Normally connected to both sides of a household breaker box so it uses both 120vac sources, 180 out of phase to provide "240" v power, which is actually just 120vac power between each hot and the grounded neutral, but 240 between the hots due to being opposite phase. Adapting a 5-15 to the 14-50 can't be done any other way. The hot goes to the hot(s) The grounded neutral goes to the grounded neutral. The ground goes to the ground. There's 120vac available between the 'hot' flats and the grounded neutral, but 0vac between the hots since they are in-phase. Am I missing something? Should only one hot prong (or socket I guess) have the 120? And how does any adapter, sourcing from a single 120v outlet balance anything between both sides of a household distribution panel? And why would it matter? It's not like running 15a worth of fans in one bedroom is going to smoke my electrical system because it unbalances my distribution box.
How is plugging any 14-50 device into a 5-15 outlet safe? Barring some type of setting on the device itself to alter what it draws, it will try to draw that 14-50 amount. Tesla mobile EVSE has switchable plugs available for different outlets. Having a certain plug attached likely makes that switch to the EVSE on what electricity amount it can draw.
But I don't know of any houses built with a 120 V / 60 V split-phase input (or 120Y/69 three-phase input). I think a dual-voltage EVSE would be more useful if, when set for 120, it expects to find the 120 from a single leg of its input to neutral.
Can you induce phase difference by making one of the wires x amount longer than the other? (Didn’t learn much AC in school)…
The usual way would be to use a center-tapped transformer, like the ones that come with the PlugOut Power inverters and weigh 30 pounds or so. Actually delaying one wave by making the wire longer is an interesting idea. To invert the phase of 60 cycle-per-second AC, it would have to be long enough to add a 1/120 second delay. Most communication cables I've seen that specify a propagation rate seem to list something around 0.8 of the speed of light. So a wire about 2000 km long on one side of the adapter ought to do it. A loop from Hunstville to Oklahoma City and back, say. To keep the resistance down, that would have to be very heavy wire. You might avoid laying it out to OKC by coiling it up more, but then there would be induction effects to take into account. Probably why more people seem to use a transformer.
