Big OzInverter, torroids question?

[ClockmanFrance]

PJ safety fan connections.....

[frackers]

The PJ safety fan was 12v. Their is a socket on the control board that gives 12v and it runs my 'OzCooling' circuit with 2 off 12v 120mm fans.

Thanks for that - I'll look for a PC chassis fan...

Just been putting the epoxy onto the first winding layer - what a disaster! I'll know next time to just do the top (i.e. mix up not very much!!) and when its gone off turn over and do the other end.

I had to scrap the half hardened resin off where it had formed a rim round the base that was sitting on a plastic sheet. I'm using R180 resin (if that means anything to anyone) which has the constancy of water after its mixed with the hardener. At least I sensibly choose the slow harder so I had time to rectify most of my mistake of just a bit too much resin.

Problem now is that it is so thin a resin that it hasn't really stuck anything to anything else  Not sure if I'll bother with the next 3 layers.

To add insult to injury, when I was trying to recover things one glove got a hole in it so I had resin all over my fingers and I was busting to go to the loo!!

Sticky moments 


I think I'll sit and look at it for a day or two and may very well strip it and start again...

[ClockmanFrance]

With most resins you can use chalk powder as a thickener, mix it well with the epoxy first before adding the hardener.

Try a little test batch with a little epoxy and see how you get on, chalk also slows down the hardening process.

Quantity of epoxy I used each secondary was about 20 to 25ml.

[frackers]

Having found a crossed over wire, I'm going to strip back to bare metal and try the flap wheel to radius the edges. The gluing problem is mostly down to the corners being raised by the half-round of thin pipe I used to protect the wire from the edges and hence lifting the wire from the core.

[frackers]

Done!!

60 grit flap wheel (which I found in the toolbox) certainly did the job of rounding off the corners and I have the first layer of mylar on it.

Hopefully tomorrow night I'll get back to where I was - but better

[frackers]

It has taken nearly a week but the first layer is now on and the "colloidal silicate adhesive filler" mixed into the epoxy has done a great job locking it all together (well one end anyway - got to turn it over and complete it tonight!!)

Question - is it recommended that the layers all start and stop at the same place or should there be a bit of offset to allow the tails to emerge from the bottom layer(s). Not looked at any photos closely enough to see but not sure it would be obvious even if I did!!

[oztules]

i use same place...

[ClockmanFrance]

I start each time at the top.

Right angle then adhesive mylar tape the copper, then its up and over and down the hole.

I finish each time at the bottom, then more adhesive tape.

You can see the epoxy in the photo, but this is the second to last secondary, the 3rd.

[ClockmanFrance]

The Big....

Just the cores is 35kgs.

[frackers]

Thought it might be interesting to demonstrate my bicycle rim toroid winding technique. The clip starts off with showing the size of the rim (400mm).
Note the red tape marker so I can count how many turns of material I load onto the rim. The mylar needs 22 turns and the wire (for 96 turns on the toroid) is 36 turns.

The winding of wire I'll capture later in the week - basically the same but a bit of tape to stop all the wire falling off the rim.

https://www.youtube.com/watch?v=RbuXQ005wE8

Enjoy

[bj]

   Now that is absolutely brilliant.
   Thanks for the share

[frackers]

   Now that is absolutely brilliant.
   Thanks for the share

Thanks for the complement bj

This next clip is the rather messy wire winding - the result is OK and it means no joins in the winding but it is time consuming and takes a fair bit of work to get a tidy result.

https://www.youtube.com/watch?v=kYtudDVucUo

It has worked 3 times as that is how many layers I have now!

I was hoping to get a fourth layer on but a trial run with the primary makes me think it won't fit. It weighs in at 31kg now so assuming the mylar and epoxy doesn't amount to much that is at least 5kg of copper on it.



Does the primary need to be all nice and tidy or is it just a matter of getting the wire through the hole? The 3 secondaries are 1.8 mm diameter wire (2.5 sq mm cross section), is that likely to be OK up to 6kw (25amps) or would I be pushing my luck

I have removed the outer (orange) insulation layer from the 50 sq mm welding cable and if I can find some heat shrink then I could go thinner by stripping the white layer but I doubt I would gain a lot for the amount of effort involved.

And just to make my day the LCD on the turbine controller died - random dots flashing all over. I think the 34C outside temperature cooked the battery shed (was over 40C inside) so I've had to hack the code to use an I2C connected display that I had to hand.

Ho hum...

[ClockmanFrance]

Interesting winding technique frackers......

As Oz has said, just get the primary through the hole in a tidy fashion.

I ended up with one 50mm/2 primary overlapping.

[frwainscott]

 I guess im going to get in on the FUN attempting A BIG OZ Inverter. I have ordered boards for 48 volt Input ,220 Volt Output ,Split Phase...............  Should be interesting! They were out of 15KW sets and don't know when they will have any so im going to get the 10 KW set. Think I might order A 24 volt set also to start with.Build my system up slowly. Anyone needing the three wire fan it is a cpu cooling fan for intel processor, or amd processor.

Im having A hard time finding toroids around here. But think I have found 2 - 2.5 KW toroids.

Also need any advice on cleaning the boards, from what ive seen they come with all sorts of crap on them....... Frank   :-)

[frackers]

The hunt for the ferrite 'E' cores started in earnest last night - and this turned up



Using 2 of the 'C' core sets I can make an 'E' core!!. Not sure if it will work though



I could double up the thickness and there is certainly room for the 3-4 turns of 50 sqmm wire but inductors are a bit of a mystery to me!!

Should I test a few turns and see what inductance I get? (I have a cheap LCR-T5 meter)