Guru
Joined: 21/06/2018
Location: AustraliaPosts: 1191
| Posted: 02:02pm 08 Jun 2024 |
Thanks for that Dex it is very revealing. It tells me the servo loop from the DC input through inverter transformers choke etc to Ac output& fed back around the loop to the voltage feedback is happy. I deduce this because the two modulation percentages are almost the same. If there were impedance problems anywhere the % would increase to make up the shortfall.
I suspect that if you measure with an AC RMS voltmeter at the two pins feeding back the AC output right at the Nano control board it will have exactly the same voltage reading of 230.5 give or take half a volt for the instance of no load and ~8A load.
It appears there is impedance between the 230V transformer output and your multi function meter. It can be roughly calculated by using the difference between the loaded and unloaded AC voltage which is ~ 16V and the current difference is ~ 7.8A that tells me there is a voltage drop between the AC output winding and when it finally is measured by the meter. The resistance you are looking for is ~16/7.8 or around 2 ohms.
Maybe you should grab a true RMS meter and start hunting. Hint, at 8A load, measure (ACV) between the same active wire immediately at the closest point to the toroidal with the other end of the meter to the active out of the multifunction meter, note it - then do the same at the other end of the 230V mains wiring (neutral?) from tranformer to meter neutral out. Add the two noted AC voltages together and I suspect the sum will be damn close to 16VAC. Good luck and be careful probing !! Note the AC output probably passes also through the Mains contactor/relay assuming you installed one, it obviously needs to be closed to measure the voltage drops. Welcome to ohms law. (I hope this is all correct I hate humble pie)
Do you have an AC line filter in the 230VAC circuit too?
Edited 2024-06-09 00:33 by wiseguy