We seem to have made a serious error in refitting our boat and purchased a 240v AC induction stove (we are in Canada and everything runs on 120v AC). The manufacturer told us we could use an autotransformer connected to our quattro to step up to 240, but this seriously complicates the downstream AC on the boat electrical panel and given space limitations would have AC running back and forth across the boat at different voltages in an alarming way. Does anyone know if I can run a 120v line from a 15 or 30 amp breaker on our breaker panel to the transformer and then connect this directly to the stove (and how to ground it properly)? The amps would be limited, but we could manage this. We would alternate between using the inverter and a 30amp 120v shore power connection, depending on where we were.
Iâm thinking it will not be a good experience for you to do what you suggest because I think you will overload the AT and it will shut down due to heat. The AT 100A does not mean it can provide a 100A 240V circuit from a 120V input or vice versa. It can pass-thru 100A, but can only transform a maximum of 28A for a short period of time. I think it would work to run one or maybe two âburnersâ for a short duration, but it wonât run the electric oven.
I have two suggestions:
- Replace the 240V induction range or cooktop with a two-burner 120V counter-top induction cooktop. I use one inside my RV and a single burner model for cooking outside.
- Add a second, identical Quattro along with an AT to your existing system. The AT will balance 120V loads across the two inverters, which is what it was primarily designed for. Your 240V appliance will run directly from the two Quattros and youâll likely have enough power to bake a cake in the oven
Even if you have a 240V/120V system inside the boat and just a 120V 30A shore power connection, you will still be able to charge batteries from one of the Quattros.
That is how you would do it assuming the AT limitations above can power the induction stove.
The autotransformer neutral can do 28A continuously as long as it doesnât overheat.
You are in a step-up configuration, so you will get a maximum of 14A continuously at 240V (minus some for losses). It can do higher current for short amounts of time. The trip mechanism is purely thermal, unless you exceed the breaker rating. Therefore, the 32A version of the autotransformer is probably a better fit for this application.
This is 3360W maximum. If your induction stove needs more than that continuously, it isnât going to work. I wouldnât even want to get close to that. I would also be concerned about induction cookers switching off and on causing annoyance trips if you are close to the edge.
The largest single pole 120V breaker you should run is probably a 30A. If they make 25A breakers, that might be better. You would feed it into the one of the autotransformer lines and neutral. An L2 will be created that you can feed into the oven along with L1 (and Neutral, if required). No ground relay needed here.
Ed has also provided great advice above.
See Autotransformer Manual: 2. Introduction
Section 2.3.2 Stepping up voltage
not sure on Canada electrical code, but autotransfomers are not legal (NEC) in the USA, I would highly advise against using one.
buy a new cook top, but if you have to use this one you want a step up isolation transformer, hire a local electrician they can size and install it properly for you.
end of day best solution is new 120v cook top
Thanks all. We were leaning heavily towards just eating the cost and getting a small induction range instead, so this was a good âgut checkâ. I can mess around with gimbals and clamps without worrying about zapping my family working with too many voltages.