โMar-22-2019 07:20 PM
โMar-25-2019 11:26 AM
DrewE wrote:pianotuna wrote:
Hi,
Except that every hybrid inverter/charger (those with load assist) has an autoformer inside.DrewE wrote:
This makes good sense; if an autotransformer were used in a converter, you'd end up with a neutral/ground fault by design in the RV, and also significantly increase the risk of a hot skin condition. on the RV.
Are you sure about that? The manual for the Magnum hybrid inverter/charger states that "The AC output neutral conductor and the DC negative conductors are not connected (bonded) to the inverter chassis. Both the input and output conductors are isolated from the enclosure and each other." If there is an autotransformer in the circuit, it is not bridging the AC and the DC sides (i.e. there's some other means of providing isolation). I would guess it's instead a normal transformer with separate windings, but I really don't know anything of the details of their circuit topology.
It's entirely possible to make a voltage boosting transformer that is not an autotransformer; it just typically requires more copper or whatever metal is used for the windings and generally a larger core and so is bigger, heavier, and more expensive.
โMar-25-2019 10:25 AM
Dutch_12078 wrote:time2roll wrote:Dutch_12078 wrote:Still the system probably meets code as it was never anticipated how RVs would become such power hogs even having power management systems to keep that 30 amp outlet at the very max for extended periods if not 24/7.
If a park is seeing a significant voltage drop when full then the park infrastructure is substandard.
The park may have met code when it was built, but current code sets the minimum required percentage of 50 amp versus 30 amp sites, along with other changes over the years designed to support newer RV's with high power requirements. A standard 30 amp breaker only supports a sustained 80% load (24 amps). A well designed park electrical system should also support a sustained 80% load. The problem isn't RV's with higher power requirements, it's parks that haven't kept up with the RV market changes.
โMar-25-2019 10:05 AM
pianotuna wrote:
Hi,
Except that every hybrid inverter/charger (those with load assist) has an autoformer inside.DrewE wrote:
This makes good sense; if an autotransformer were used in a converter, you'd end up with a neutral/ground fault by design in the RV, and also significantly increase the risk of a hot skin condition. on the RV.
โMar-25-2019 09:59 AM
Dutch_12078 wrote:westernrvparkowner wrote:
You can look up the proposed NEC changes for yourself. The NEC isn't some proxy for irate park owners. It carries the weight of law across the country since every jurisdiction I know of requires compliance to the NEC.
NEC Article 551.20(E) "Autotransformers. Autotransformers shall not be used."
That's been in the NEC since at least the early 80's. I haven't looked back any farther than that...
โMar-25-2019 08:48 AM
DrewE wrote:
This makes good sense; if an autotransformer were used in a converter, you'd end up with a neutral/ground fault by design in the RV, and also significantly increase the risk of a hot skin condition. on the RV.
โMar-25-2019 08:27 AM
โMar-25-2019 08:14 AM
Dutch_12078 wrote:westernrvparkowner wrote:
You can look up the proposed NEC changes for yourself. The NEC isn't some proxy for irate park owners. It carries the weight of law across the country since every jurisdiction I know of requires compliance to the NEC.
NEC Article 551.20(E) "Autotransformers. Autotransformers shall not be used."
That's been in the NEC since at least the early 80's. I haven't looked back any farther than that...
โMar-25-2019 03:42 AM
Dutch_12078 wrote:
NEC Article 551.20(E) "Autotransformers. Autotransformers shall not be used."
That's been in the NEC since at least the early 80's. I haven't looked back any farther than that...
โMar-24-2019 08:58 PM
โMar-24-2019 08:41 PM
โMar-24-2019 08:27 PM
time2roll wrote:Dutch_12078 wrote:Still the system probably meets code as it was never anticipated how RVs would become such power hogs even having power management systems to keep that 30 amp outlet at the very max for extended periods if not 24/7.
If a park is seeing a significant voltage drop when full then the park infrastructure is substandard.
โMar-24-2019 07:48 PM
Dutch_12078 wrote:Still the system probably meets code as it was never anticipated how RVs would become such power hogs even having power management systems to keep that 30 amp outlet at the very max for extended periods if not 24/7.
If a park is seeing a significant voltage drop when full then the park infrastructure is substandard.
โMar-24-2019 06:52 PM
wnjj wrote:Dutch_12078 wrote:
Those "50 ampers" cannot pull more than 30 amps through the 30 amp breaker, and 15 or 20 amps using a separate cord plugged into the breaker protected GFCI utility outlet. None of the 'Y' adapters, whether commercial or homemade, will work with an NEC compliant park panel.
The larger RVโs are more likely to max out the 30A and also may want to use the 20A at the same time. Many have load shedding systems and/or inverters that can max out draw. A smaller 30A rig may not even have the means to even pull 30.
โMar-24-2019 06:25 PM
pnichols wrote:3 tons wrote:pnichols wrote:
I guess that this discussion thread points out a disadvantage of staying in hookup campsites.
We drycamp a lot in as much as possible campgrounds with good spacing between the sites and often when it's hot - so we can just use the generator to provide full power at full voltage to our RV. ๐
If a hughes autoformer is positioned between the genny and the air conditioner, I would think that it would help guard against voltage sag upon compressor start...
You hint at a very good point!
Instead of a Hughes autoformer, maybe the ultimate for us drycampers would be to install one of these in our coach air conditioner just to be on the safe side: https://www.microair.net/collections/easystart-soft-starters/products/easystart-364-3-ton-single-pha...