KeepIS said  

  Surprised that I got the three Toroids done a lot faster then I remembered taking the last time, then I recalled that I had carefully unwound the 230v AC windings back then, in this strip down, I cut the windings off as I had no use for them  

Gulp What!!!  You just cut it off  ... that's terrible.  

I know it's quicker but I couldn't do that, I'd feel too guilty.  

Anyway, what were these toroids from in their previous life. And what diameter is that wire?

And when you fit them together, do you put anything in between to protect the windings from each other  ...  especially where there are high spots pressing together.

Best to use some high temp epoxy potting compound to keep them from vibrating too much and causing a short.
I use high temp pvc with adhesive to wrap up the secondary winding. Works really well. Some people call it high temp mylar wrap.
Edited 2024-07-20 14:57 by Cpoc

Yes, loved every second of it  

Not in the slightest  

2.56mm on the dig caliper.

Yes, two thick compressible circular separating sheets, thick insulator on the base.

Center open, convection and forced air cooling when/if needed. On both Toroid stacks, 6 toroids in all    

I love wrapping secondary toroids as much as having my teeth pulled.

I love wrapping secondary toroids as much as having my teeth pulled.

  Cpoc said  

Best to use some high temp epoxy potting compound to keep them from vibrating too much and causing a short.

The existing three don't vibrate, quite as a church mouse except for the very occasional heatgun, or my Wife uses a hair straightener, both caused from a Diode in series with AC on LOW. Yes, I've read about micro vibrations, but that is a whole other discussion when you look into it.
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Edited 2024-07-20 15:07 by KeepIS

I can see you used some high heat tape. It should not be problem.

BTW: They will be partly wrapped with fiberglass tape when stacked 3 high.
.

That Toroid wrapping looks good. I am not looking forward to wrapping mine with AWG 9 gauge which is 2.9mm thick. Not looking forward at all. At least it’s only one layer and I did not have to wrap 2 layers each for 6 Toroids

BTW in case it's not obvious, I did not wind these, they are the existing windings,  93VAC and wound first on the Core in these Toroids.

  Cpoc said  

That Toroid wrapping looks good. I am not looking forward to wrapping mine with AWG 9 gauge which is 2.9mm thick. Not looking forward at all. At least it’s only one layer and I did not have to wrap 2 layers each for 6 Toroids

Se my last post, and I would seriously not want to wind these and especially your cores, you have my sympathy, but some people love doing that  

  KeepIS said  

BTW in case it's not obvious, I did not wind these, they are the existing windings,  93VAC and wound first on the Core in these Toroids.

You cheated!  

       

I hate winding secondary cores…it hurts my hand how could some people enjoy this. I know some people do enjoy it but not me.

Test setup ready for a 14 turn primary which I pick up in the morning, basically a 200mm X 200mm round lump of copper and steel, a bit taller when the primary is fitted.

I'll check the output against the existing toroid stack, if it's in the ball park and other tests pass, I'll do the final assembly of the transformer.

Next is building the 5 inverter housings. Two separate housings allow each toriod 3 stack transformers to be lifted on and off separately, a 3rd housing for the two power boards, the 4th housing for the Nano controller, input switching, DC current sensors, LCD and other monitoring hardware. The 5th housing is for the AC HI/LO combiner, AC filtering, separate AC monitoring and AC circuit breakers.

This will make it easier for a repair or modifications to be carried out, otherwise I would need a block and tackle, as others have had to employ, if this inverter was constructed as a single housing assembly.  


Edited 2024-07-21 07:17 by KeepIS

Very happy, the 2nd 3 stack transformer with 14 turn primary has exactly the same AC input to output voltage and power reading on the Variac.

Found some different low cost toriods for the chokes. A larger hole and similar size, they needed an extra turn for the same inductance, I still have to test saturation current to be sure they will do the job, I can always use an extra core if needed at the price.

Picked up the cable for the chokes this morning as well as the Primary winding for the 3 stack transformer, it took just under 8 meters of cable for 14 tight turns.

EDIT: Now running in the test inverter, and with incorrect lower value chokes it's idling at 23 watts @ 241vac, hopefully I'll get the chokes tested and running tomorrow before a forced lay off, and hopefully only for a few days
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Edited 2024-07-21 16:34 by KeepIS

This 2AWG 35mm2 cable is rated at 188A continuous. The Weld Flex rated at 220A is a bit thicker and did not feel as flexible in cold weather, decided to go with first cable.

Each toriod will only be required to handle around 3kw continuous, and that would be for around 1 hour a day worst case, so a total of 6kW continuous for 1 hour, the current single 3 stack inverter can do that, and start huge Induction motor loads.

A lot of 2AWG cable from typical electronic and electrical outlets appears to have a very thick but still flexible covering, however some of it is only rated to 150A with no indication of duty cycle.

That 150A tinned copper cable (I know tinned is dearer) is currently almost twice the price that I payed for the 188A cable, and 15 months ago the 150A cable was 30% cheaper, even then it was still a lot dearer than this higher rated.

2 B&S (35mm2) 188 amp Copper Cable Single Core Australian Made
Nom Area: 32.07mm2
Rated to 188 amps Continuous Use
Applications: Battery and Starter Cable, Inverter, Dc-Dc Systems
Conductor: OXYGEN FREE Plain Copper Wire to AS/NZS 1125
Insulation: V90 PVC to AS/NZS 3808
Australian Made
UV Stable
5V90 PVC Cable

As with the first 3 stack toriod, a heat gun on low heat is used to warm the cable on each pass through the toroid, especially each bend, it sure makes it easy to pull straight and get tight curves around the toroids, and shortly after removing heat, the cable holds shape and does not try to unravel.
 
I will also seal the crimp connectors when final lenght has been determined.




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Edited 2024-07-22 11:20 by KeepIS

Looking really good. Everything is getting very expensive everywhere. Our dollars and euros have no more value. Food was really cheap in Portugal not anymore.

Double Post
Edited 2024-07-24 13:04 by Cpoc

Haven't been able to do much with my hand for past few days or the next few days    

This gave me time to ponder and look at various low battery voltage and restart voltage conditions in the Inverter. I ended up adding one more setting to the firmware, this will allow the inverter to restart with a degree of battery charge when high to medium rate of charge is being employed, and it is adjustable.

In the mean time I'm gathering the the cabinet material, hopefully I'll get into that soon.