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For example the daisy chain is set up such as output of master is connected to input of slave. The slave can be programmed with always on for power share mode or standby mode. When the master needs help it’s calls upon the slave to help power load share.
My question is what happens hen you connect grid power or generator power to the input of master. Normally it goes either into charge mode and/or pass through mode but what happens to the slave. Does the master send a signal off command to the slave or can the slave work using battery power in power load share mode.
This was going to be a serious issue with the previous method I was attempting to use for parallel/daisy control. That previous method was grid-tie frequency shift, where a positive frequency shift--going from 60Hz to 62Hz--from the master would shut down the slave. Worked alright with long cabling between the inverters (not at all with direct cabling though!)--but this would cause a serious issue with a generator/grid input at the nominal 60Hz meaning "full power ahead" from the slave unit.
I am currently working on revising it to a frequency droop method--so under load, the "master" inverter's frequency actually FALLS (i.e. no load = 60Hz, full load = 58Hz, kinda like an overloaded generator 😉); when the slave inverter recognizes this frequency droop, it proportionally throttles up power output based on its wattage capacity (i.e. 58Hz = 100% capacity). This means that if a nominal 60Hz input is applied via "input" from the master inverter, the slave inverter(s) will be in idle/off state. Unless that little camper generator overloads and starts to load down--then the slave will auto kick in to offset the load with power from the batteries.
That makes sense but please have this option for 50HZ as well. I am planning on using 230v 50HZ with custom hand wound transformers. This is for my future new boat project.
Another questing that is not related to this. I am planning to build 2 new transformers hand wound and want to know if these cores would be enough. I will double stack them but I am not sure if the magnetic flux in the cores can handle the 12kw load. I would build the larger core the smaller one I have build already and I gave away.
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That makes sense but please have this option for 50HZ as well.
You betcha 😉 . Mathematics work just as well on either frequency option. It's a calculated difference between "system nominal frequency" and "measured input frequency" that makes the difference to the "slave" inverters. Or a calculated offset between "system nominal frequency" and "output frequency" for the master.
Another questing that is not related to this. I am planning to build 2 new transformers hand wound and want to know if these cores would be enough. I will double stack them but I am not sure if the magnetic flux in the cores can handle the 12kw load. I would build the larger core the smaller one I have build already and I gave away.
More of a question for @ben. I personally don't know too much about the nitty-gritty mathematics of transformer cores...my motto at least for now more or less is, "if you can't get enough wire around the core to carry the desired wattage, it's too small!" Determining the tesla value of course is highly important, as that determines how many turns are required to reach the desired voltages on each coil--and of course, directly affects how much wire is needed for the desired output.
The Tesla value now that is where I get confused. I read up on that and still don’t understand it. As for wiring up the core should not be a problem with the larger core with 14 gauge wire for the secondary and 11 gauge wire for the primary. I just wanted to know if the double stacked cores would be enough to handle the 12kw load. As for the second inverter well let’s just say that 99% of the time is will be on standby. It’s more of a fail safe if sometime happens to the master well then the slave can become the new master. This is insurance when I am off grid and crossing the Atlantic. It’s better to have something that you will not use then need something you don’t have.
This is insurance when I am off grid and crossing the Atlantic. It’s better to have something that you will not use then need something you don’t have.
I sure agree! No parts stores 'round the corner out there, that's for sure!
As for wiring up the core should not be a problem with the larger core with 14 gauge wire for the secondary and 11 gauge wire for the primary
Multiple strands of each I presume...
The Tesla value now that is where I get confused. I read up on that and still don’t understand it.
Most of us mere mortals without 5 inches of mathematical calculations (and careful analysis of the ore that the core came from)...find this by trial and error. If you're winding your own trannies, you're probably quite familiar with the process. I'd say...if you can get enough wire around the core, you'll probably be just fine.
Yes multiple strands and multiple layers. With Mylar tape in between each layer as well. I know how to wind it up I just don’t know how to select the right core size. I know the double stack smaller core was overkill for the ozinverter. Even at full 6k it did even get warm. So I believe the larger core double stack should be enough for a 12k load. Again I am not an engineer and I don’t know how to do those calculations.
Me neither. I'd say...if the core is a good material, you'll be more than set, no problem. @ben had a bit of an issue with a smaller PJ core (had "hot spots" where parts of the core got hot, and others didn't), but other than that, no issues. Seems in my experience--with stock PJ trannies anyway--that at least 90% of the heat generated is from inadequately sized wires...the cores are good.
The ore is the proper one. I have found the correct supplier in China that makes the right cores and they have both those sizes in stock. All I do is double stack them for more magnetic flux and less wire turns needed due to the stacked core hight. Since I hand wind them the double stacked cores come in handy. But I will not do them for others. My first core was a learning experience and hand winding cores are not fun.
My first core was a learning experience and hand winding cores are not fun.
I've sorta rewound one smaller tranny...and decided right then and there that I wasn't going to do it again 😉. Hat's off to those of you who willingly do it over and over again...
As for me I make sure the wires are calculated correct. For the primary winding I use the mm2 chart for 210 amps for 6k and 420 amps for the 12k
Hand winding 1 or 2 cores ok but he’ll I would not wind any more than that. You need a really machine to do any type of production runs.
also Interested in 50hz version 220~250v range for use in Australia
all of the HF inverters ~ 30kw I have tried just keep popping running my Aquaponic setup ~15kw , wanting to go to LF inverters
any data logging available to see loads of each inverter ?
also Interested in 50hz version 220~250v range for use in Australia
LCD setting: you can select between 50/60Hz ...OR...trim the frequency between 40-70Hz in ~0.25Hz increments.
Output voltage can be adjusted as you see fit, 180-270v for a 240v spec should be quite doable; keep in mind, though, that the higher the output voltage, the higher the input voltage needs to be, or it'll start to flatten out a bit (lack of headroom).
any data logging available to see loads of each inverter ?
At present, data can be pulled from each inverter via the MQTT broker. I plan to get an isolated RS-485 / RS-232 port on the inverters as well (at some point!) for direct data readout. Probably before that, I'll be implementing a "local server" on the WiFi board, which can connect to a local WiFi network, and be accessed/queried via mDNS. Read a "stats.json" file for all the current stats, access each inverter by it's ID number, etc.
There is presently no internal time-based data logging on the inverters, though that technically is possible--to some extent, as there is no RTC (real-time-clock) in the inverter...