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Users Projects / Re: y Philippines Retirement Solar Off Grid System
« Last post by lighthunter on Yesterday at 07:46:34 am »
The circuit above is simply a capacitor charge pump driving a rectifier bridge supplying power to a 24v relay coil. (The 250 ohm represents the coil resistance) when the sources are in sync, the relay has no power and drops out giving your transfer circuit the safe to switch signal.
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Users Projects / Re: y Philippines Retirement Solar Off Grid System
« Last post by lighthunter on Yesterday at 07:18:17 am »
Hi S/N,   

I agree with Ross post.
I hear your concern about the transfer hiccup. Though i never had a fiber modem to worry about, A loaded refrigerant compressor will make a unfriendly noise with a huge surge if the transfer isnt done correctly.

Doing the math with 50 hz and one full cycle of time is 20 milliseconds. This is the minimum delay that should be used. Theoretically 1/2 cycle would be enough but to be on safe side... 20ms or greater.  This is similar to a double pole relay. Most ATS specs are around 50 ms.

20-50 ms shouldnt bother most equipment.

If you want to make it even smoother add a permission input to your arduino. Then connect it to the contacts of a phase align detector. (Below) Its really crude but works beautifully. The relay drops to deenergized state when there is no danger of misalignment.

The final step i would do is place a low wattage filament light bulb in series with each source (inverter and grid) in this case.
And connect your new modified ssr ATS up to each bulb source and connect a third bulb as the load. Initiate many transfers and watch the bulbs each transition for flickers or brightness changes. If all goes well you wont even loose a light bulb, if you do, at least its not your inverter :) By doing this you could tune your settings for best performance. Whatever you find as a lowest time delay, i would double it at least to give margin for unknowns like temp change behavior.

I never went that far, i got excellent performance with A JQX-62F 80A relay and the sync circuit so never went further. One more thing to consider when comparing an ssr to a relay...  A transfer switch has a terrible life. It has to bear the abuse of every possible scennario such as a 2HP water pump on startup if the transfer happens during such an event then surge current could easily exceed 100 amps. Physical contacts are better suited for these unknown extremes than an SSR. Even if subjected to this abuse they wont usually fail immediately and if sized appropriately they can be inspected with magnifier and changed before an inverter gets hurt. Just 2 cents. The SSR scheme can work i think ive just never done it and am thinking sizing is critical. Ive friends whove physically dismantled dragon brand ssrs to find components less than half the rated values so be careful of that as well. The failure mode of a mechanical relay is usually welded contacts which prevents switching but doesnt have to ruin inverter. If ANY breakdown of an SSR happens it will almost surely leave debris for the partner device to trip over kind of like an H bridge failure in your inverter, all it takes is one to fail and usually wipes out every one.
Im sure it can be done succesfully just have to design for the worst case.



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Users Projects / Re: y Philippines Retirement Solar Off Grid System
« Last post by rossw on Yesterday at 05:48:09 am »
There’s absolutely no delay between relays switching.

Triacs and SCRs will typically stay turned on until their A1/A2 (or A/K) current falls to zero.
So if a triac is triggered at say, 10 degrees, it will stay on until 180 degrees.
If you turn on the OTHER SSR at 12 degrees (after "removing the trigger source) of the first one, you'll have almost a complete half cycle with both devices on.

Quote
If a triac has a voltage/current on both legs nothing on the gate, will they interact?

Most triacs can also be triggered with a high dV/dt on A1/A2.

Quote
There’s a circuit called “zero cross” ties to the gate and one leg of the triac.

Zero-crossing is a technique used to try to reduce RFI/EMI and overall stress. By triggering the device at "close to" the point the waveform crosses zero,
there is minimum current, so minimum switching noise.

Again, the warning about "trigger at some point, and the device remains "on" until current reaches zero (typically the next zero-crossing)
Triggering on zero, and off at zero means your devices are always on for multiples of half-cycles.
You REALLY need to watch your triggering to keep the magic smoke inside the packages.
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Users Projects / Re: y Philippines Retirement Solar Off Grid System
« Last post by solarnewbee on September 23, 2021, 08:44:12 pm »
Maybe I should post my code. There’s absolutely no delay between relays switching. Of course the goal was to get rid of the long delay that was shutting down TVs, fridge, modem on a daily basis. Son in law works as a call center operator for T-Mobile here  and when the modem drops out he loses calls. Fiber modem takes 3-4 minutes to acquire which is weird. Something else I failed to incorporate was a battery backup for the Arduino that’s powered from the grid. If the grid does something flaky and the Arduino becomes unstable then rapid switching may occur. At the very least the inverter will get hit with a sudden rapid on/off load. Somewhere I have a MeanWell psu din rail mount that has a battery input and supplies 5&12v.




    if  digitalRead(inverteron_pin4 == HIGH);
         digitalWrite inverterssr_pin5 HIGH;   Looking now maybe this line should be second
         digitalWrite meralcossr_pin6 LOW; this line first maybe a delay 50?
     else
         digitalWrite meralcossr_pin6 HIGH

If a triac has a voltage/current on both legs nothing on the gate, will they interact? Is there a device to put in between the 2 sets of SSRs that will divide the 2? Diodes won’t do it. 🤔

There’s a circuit called “zero cross” ties to the gate and one leg of the triac. Can’t find an explanation for what this does but assumption says it prevents what happened to me with the house circuit paralleled to both sets of SSRs. My other thought was that inverter was out of phase with the grid. Never have check to see if we have a mains neutral. I will now tho.
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Users Projects / Re: y Philippines Retirement Solar Off Grid System
« Last post by lighthunter on September 23, 2021, 08:13:27 am »
Wow youve got a lot in that last post.

1/4 watt R will work fine.
Regarding ATS, ive had plenty of woes with contacts, sacrificed plenty FETs. Now its a large long throw 80Amp dual pole with a phase sync detector and havent lost a FET since. Not sure why youd want SSR type....
The switch sequence you describe sounds like a problem but maybe im misunderstanding. 

"
I took220v from the inverter to a relay, relay contacts close on 5v to pin4 to pull-up to bring pin 5 high activating the inverter SSRs. Then pin 6 goes low deactivating grid SSRs. Vice versa for switch to grid.   "

This to me reads like you are doing make before break with ssrs, unless your two sources are synced and at same voltage, fuses and every other weak point will clear.
I must be misunderstanding.

Your mechanical ATS would have the load on the pole and inverter on one throw while grid on other throw. This allows a brief moment where neither source is connected to load making it impossible for the two sources to fight.  The ssr needs similar scheme where the one in use deenergizes first then short pause before the other energizes.

Sounds like you got the repair going the right direction!

All the best!
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Users Projects / Re: y Philippines Retirement Solar Off Grid System
« Last post by solarnewbee on September 23, 2021, 03:00:56 am »
Only wish I could recreate the setup the 10 minutes prior to the blow up to see if there some bleed over. Looks like I’m going back to mechanical ATS. The switch over was so smooth and quiet. I took220v from the inverter to a relay, relay contacts close on 5v to pin4 to pull-up to bring pin 5 high activating the inverter SSRs. Then pin 6 goes low deactivating grid SSRs. Vice versa for switch to grid.

Checked for voltage leak across the SSRs and get just .34v. Of course thing maybe be different when you have voltage coming from both directions. Could be all coincidence and something else has occurred. The top is always off for cooling the transformer so I or someone else could have dropped something in there or the transformer has shorted. In that case I have a spare, nope, it’s 24v Damn!
What’s normal readings for a 48v transformer?

Replaced a popped transistor on the LF board. Could just make out it was a 2A and found one on a 8kw board. It’s now a donor board. I have a drawer full of irf1405 fets. By the data sheet they beefier that the ones in there and gate voltage range is the same.

I have a dandy little smd multimeter I picked up on aliexpress and it’s really nice. All the 47r were blasted leading up to the fet  gates. Everything else is within range.

Put LF board back in and it fired up and acted normally as in tried to run but got no feedback so shutdown driver and whatever other circuit on the board lights up. Flashed a few times like it was hunting driver was solid on. Of course with no fet boards in those first few rows nothing happens.

Powerjack got out of the grid tie and battery charging business. All the tracings are on the boards but the components are missing.

I could order new smd resistors (16) and wait another week or solder in some 1/4 watt. Any thoughts?

Next?
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Users Projects / Re: y Philippines Retirement Solar Off Grid System
« Last post by Pete on September 22, 2021, 05:32:26 pm »
Hi Solar, the inverters that have blown up on me, Powerjacks 8kw. Have taken out the mosfets, the driver transistors and also some of the resistors on the Mosfet boards.
I repaired some of the mosfet boards as spares, I ended up replacing the mosfets and some LED indicators on them plus most of the resistors. I did repair one driver board, but they are not easy to work on, being so small.
I just replaced all the driver transistors on it.
My powerjack has blown up twice using my power saw. I think it is the starting current that pulled the battery voltage down too low and caused the mosfets to blow.
I have since added a 500 Farad capacitor bank in parallel with my VRLA batteries and have not had a blow up since. My tools and air compressor start much easier too.
From what I have read Lithium batteries have a lower internal resistance and should be able to supply starting currents easily.
I did read some old stuff on this site about Oztools blowing up powerjacks when the grid failed. I think it was when he was using them as chargers and the grid failed that they blew up.
Have fun
pete
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Users Projects / Re: y Philippines Retirement Solar Off Grid System
« Last post by solarnewbee on September 21, 2021, 10:18:03 pm »
Those are some good thoughts. Will give it a try. The controller is an Arduino 2560 in a din rail. The code is pretty simple using if and else statements.

Looking at a triac I wouldn’t think it would allow any voltage across without an input at the gate. I was looking at a chart for SSRs and features included and crosscut was something that caught my eye. I do have the Chinese versions at $6 each. I’m sure all extra features have been left out. How I miss digi-key.com.
(Just thought of this)
The leds on power board and the cooling fans were still working with the battery breakers turned off. I could turn off the pv breakers and see if the batteries charge. Of course it’s not supposed to be a charging inverter. Worth a try I guess.

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Users Projects / Re: y Philippines Retirement Solar Off Grid System
« Last post by dochubert on September 21, 2021, 03:05:31 pm »

Been trying to think how to test for the 'bleed thru' of the ssr's. (Without blowing up your inverter again!)  With grid powering your house, how about unhook your inverter from the inverter ssr's and instead connect some load.  Maybe a heater.  Then use a clampon ammeter to see if there is current flow to it?

The other thought that I had was are the ssr's reliable enough to not be dropping out and re-connecting, or possibly the ats controller is doing some (very!) rapid switching back and forth.  Automatic transfer switches generally have some reliable "locking in" ability in each position to prevent erronious switching.

My limited experience with ssr's is with cheap chinese models.  I've learned to always fan cool them as they tend to fail and literally melt from overheating.  This while well within their rated loads.  More expensive models probably do better.  Don't know what you have.
Again I'm far from an expert, just throwing out some thoughts.
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Users Projects / Re: y Philippines Retirement Solar Off Grid System
« Last post by solarnewbee on September 21, 2021, 11:41:57 am »
Doc it ran good for about 20 minutes. I will have to repair the lf board. They won’t ship parts here.
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