coulomb wrote:Reading that gave me a thought. Inverters require an inductor between the inverter output and the mains to be able to send power into of out of the inverter's "output". The phase difference between the inverter's output and the mains determines the magnitude and direction of power flow. So there will be significant (~ 6% of 240 V = 14 V) of 50 Hz in that inductor.
You're thinking of the kind of inverter that can smoothly go from taking power out of the mains to putting power into the mains. But the PIP never puts power into the mains. So it has no need for, and does not have, a 50 Hz inductor.
Which inductor would that be? It has to be the large toroidal one that is connected to the inverter's output.
That inductor is for blocking high frequency PWM. I expect it is designed to be as close to a short-circuit as is practical, for 50 Hz.
The one Weber noticed gets really hot, and tried to re-wind with litz wire. (See the index for the whole interesting saga, in case you missed it.)
I not only tried, I succeeded. And the inductor did run cooler.
viewtopic.php?title=pip4048ms-inverter& ... 332#p63996
The disappointment was that it didn't reduce the no-load power consumption.
It seems to me that this inductor's core isn't designed for low frequency, and it already gets quite hot (some 100°C). So maybe when the inverter is inverted (so it becomes a battery charger) and there is significant 50 Hz in that inductor, it gets really hot. There are three temperature sensors in the inverter, one of them may sense the temperature of this inductor, or perhaps they infer it from its resistance somehow. The firmware may be forced to cut back the power to the mains battery charger when this inverter gets really hot.
I happen to have a PIP apart at the moment, so I checked. There is no temperature sensor anywhere near that inductor. And I severely doubt that they would have added the PWM-filtering circuitry required to measure its 50 Hz resistance, when adding a single thermistor near it (as they have done with the HF transformer) would be so much simpler.
I don't have time right now, but perhaps someone could carefully and safely measure the temperature of that inductor when mains battery charging? Even watching the temperatures from a Q1 command (see index) might be interesting.
I hope it is clear now, that measuring the inductor temperature would be a waste of time.
One of the fathers of MeXy the electric MX-5, along with Coulomb and Newton (Jeff Owen).