Author Topic: Another PJ journey  (Read 2393 times)

0 Members and 1 Guest are viewing this topic.

Offline frackers

  • Full Member
  • ***
  • Posts: 214
  • Karma: +9/-0
  • If it moves - computerise it!
Another PJ journey
« on: September 09, 2015, 05:54:08 AM »
I started on the Power Jack journey some months ago and have been gathering parts and assistance from a mate down the road

One thing we couldn't find here in NZ was decent torroids - no redundant grid ties here unfortunately. What we did find was some old heavy duty current transformers that maybe could be re-purposed in a different way and a couple of rolls of 1.8mm enameled copper wire.

These are the raw materials

ila_rendered

Here I'm getting down to the sailcloth and shellac!

ila_rendered

Not much wire on them and what there is is not very thick

ila_rendered

And here is what I was stripping them down for - a pile of toroids that could be rewould

ila_rendered

Having stripped 2 transformers, we have enough of the 1" thick cores to make one PJ core

ila_rendered

Part 2 will show the winder (wish I had a lathe or knew someone with one big enough!)
Robin Down Under (or are you Up Over!)

Offline frackers

  • Full Member
  • ***
  • Posts: 214
  • Karma: +9/-0
  • If it moves - computerise it!
Re: Another PJ journey
« Reply #1 on: September 09, 2015, 06:53:42 AM »
Having submitted part 2 three^H^H^H^H^H four times now and it disappearing  I'm giving up for the night.
Robin Down Under (or are you Up Over!)

Offline oztules

  • Forum Advisors
  • Hero Member
  • ****
  • Posts: 1066
  • Karma: +89/-5
  • Village idiot
Re: Another PJ journey
« Reply #2 on: September 09, 2015, 10:33:37 AM »
....... now I'm getting excited... keen to see how this pans out.

Sort of feels old school... starting from scratch..


..............oztules
Flinders Island...... Australia

Offline frackers

  • Full Member
  • ***
  • Posts: 214
  • Karma: +9/-0
  • If it moves - computerise it!
Re: Another PJ journey
« Reply #3 on: September 09, 2015, 02:52:58 PM »
The winder is based on the 3m Piggott wind turbine which is down for a service at the moment. The 1.5 ton trailer hub is certainly up to the job!!

A 'top hat' of 3mm steel with a 90mm length of tube in the centre and a  5mm MDF facing sheet was contructed.

ila_rendered

This was fixed to the hub with some spare N42 magnets - it ain't going nowhere!

ila_rendered

The start of the donor core is fed onto a layer of string - this is pulled out when the winding is completed to release the core from the former - and a sprung loaded tensioner set up (the 2x1 wood!)

ila_rendered

Robin Down Under (or are you Up Over!)

Offline frackers

  • Full Member
  • ***
  • Posts: 214
  • Karma: +9/-0
  • If it moves - computerise it!
Re: Another PJ journey
« Reply #4 on: September 09, 2015, 03:22:13 PM »
Has the anotherpower server run out of disk space? I've lost 6 attempts at uploading pictures now.

Perhaps time to check php.ini for what has been put into max_execution_time, max_input_time and memory_limit as I've seen these resource restrictions have this effect.

Robin Down Under (or are you Up Over!)

Offline oztules

  • Forum Advisors
  • Hero Member
  • ****
  • Posts: 1066
  • Karma: +89/-5
  • Village idiot
Re: Another PJ journey
« Reply #5 on: September 09, 2015, 05:30:42 PM »
Not sure of the image size limit... but your images are pretty high definition.... maybe try dumbing them down a bit

.............oztules
Flinders Island...... Australia

Offline Wolvenar

  • Senior Moderator
  • Hero Member
  • *******
  • Posts: 1397
  • Karma: +31/-0
  • Mr. Murphys pawn
    • Click here if you dont want to see your internet slowed by big ISPs
Re: Another PJ journey
« Reply #6 on: September 09, 2015, 07:53:51 PM »
Trying to make power from alternative energy any which way I can.
Just to abuse what I make. (and run this site)

Offline frackers

  • Full Member
  • ***
  • Posts: 214
  • Karma: +9/-0
  • If it moves - computerise it!
Re: Another PJ journey
« Reply #7 on: September 10, 2015, 05:17:47 AM »
Continuing the story :)

The hub/former is driven by a 24v 1/3HP wheelchair motor delicately held in place with a cargo strap. The controller from last summers project - a walnut washing machine - provides the PWM speed control.



The drive from the motor is crude but is (mostly) doing the job. The main thing is being able to get the new core out of the winder when it is complete.



So, looking at the progression from current transformer to repurposed for a PJ build.




The new cores are as expected about 205mm outside diameter



and with an inside diameter of about 90mm



Number 4 ready to roll, that will be a complete PJ torroid core unless I junk the first attempt which is a bit loose!



Robin Down Under (or are you Up Over!)

Offline frackers

  • Full Member
  • ***
  • Posts: 214
  • Karma: +9/-0
  • If it moves - computerise it!
Re: Another PJ journey
« Reply #8 on: September 10, 2015, 06:09:48 AM »
Fully resizable pix can be found at http://gilks.ath.cx/gallery3/index.php/Building-a-PJ-inverter?page=1.

This is on a home ADSL link so don't hammer it please!!
Robin Down Under (or are you Up Over!)

Offline oztules

  • Forum Advisors
  • Hero Member
  • ****
  • Posts: 1066
  • Karma: +89/-5
  • Village idiot
Re: Another PJ journey
« Reply #9 on: September 10, 2015, 08:37:11 AM »
Nicely done... hardcore transformer building ... the only thing you won't have done is make the steel itself.... cool 8)

How many cores made a single large roll...... and you can always make it bigger too :)


..............oztules
Flinders Island...... Australia

Offline frackers

  • Full Member
  • ***
  • Posts: 214
  • Karma: +9/-0
  • If it moves - computerise it!
Re: Another PJ journey
« Reply #10 on: September 10, 2015, 08:08:37 PM »
Nicely done... hardcore transformer building ... the only thing you won't have done is make the steel itself.... cool 8)

Thanks - the info you have been providing for others has been most useful in deciding to go this route. If the steel of the donor cores turns out to be no good, we still have the copper wire :)

Quote
How many cores made a single large roll...... and you can always make it bigger too :)

..............oztules

It takes 2 donor cores to make one PJ section and 4 sections (8 donors) make a complete toroid core. When no. 4 is complete I'll get the scales out!

Still have to scrounge up the mylar tape and the 50sqmm primary cable and STILL haven't looked for a box yet!
Robin Down Under (or are you Up Over!)

Offline rossw

  • Senior Moderator
  • Hero Member
  • *******
  • Posts: 790
  • Karma: +27/-0
  • Grumpy-old-Unix-Admin
Re: Another PJ journey
« Reply #11 on: September 10, 2015, 08:35:03 PM »
It takes 2 donor cores to make one PJ section and 4 sections (8 donors) make a complete toroid core. When no. 4 is complete I'll get the scales out!

Only because I'm curious and have never done it myself.... do you need to insulate the cores from each other? (That is, once you've made your 4 new larger-diameter cores, and stack them one on top of the other, do you put transformer paper or something between each to prevent circulating currents?

Offline frackers

  • Full Member
  • ***
  • Posts: 214
  • Karma: +9/-0
  • If it moves - computerise it!
Re: Another PJ journey
« Reply #12 on: September 18, 2015, 07:55:26 PM »
Certainly the original cores have no insulation between the individual sections, so I won't be using any either. What I will do is soak them (one by one) in a thinned down polyurathane varnish for a couple of days each to hopefully ensure I don't get any buzzes or rattles from them.

An interesting observation (from someone who has never really played with transformers before), if I take a length of the core material and 'stroke' it with a hefty N42 neo magnet, it is attracted very strongly but I'm unable to actually magnetise the material. It reminds me of Mu-metal that used to be used as a magnetic shield round the tube of an oscilloscope. Is it the same sort of stuff?

Robin Down Under (or are you Up Over!)

Offline MadScientist267

  • Impossible Condition Curator
  • Senior Moderator
  • Hero Member
  • *******
  • Posts: 1210
  • Karma: +22/-4
  • Rules? What rules?
Re: Another PJ journey
« Reply #13 on: September 27, 2015, 04:45:26 AM »
Can't say specifically regarding CRO shields, tho I'd imagine it would be ideal there as well, as you wouldn't want a magnetic shield developing a bias.

However, in a transformer, what you're seeing is lower hysteresis, which translates to less magnetizing current, which then translates to less loss.

The more a core material tries to keep magnetization in one polarity, the more energy it requires to "undo" that magnetization in order to flip it the other way each cycle; this energy gets lost forever, as heat.

Steve
Wanted: Schrödinger's cat, dead and alive.