Recent Posts

1

Oztules / Re: home brew 5kw simple inverter..... 20kw surge ( really), and seems bullet proof

« Last post by Sandramar on Today at 01:12:21 pm »

Hello,
Always reading these informations.
For the Feedback transformer I have got a lot of 0.5 VA small transformers 220vac/14vac . I only have One inverter in use and is not touched in years .
My question would these 0.5VA would work for the feedback transformer ?
I'm working on a transfer & charging profile for these "Oztules" inverters and I would like to use these transformers since they are  in hands and would fit in PCB  with a small footprint.
For charging purposes I'm using a transformer tap controlled by triac at high voltage side of the transformer . This tap  will increase the voltage at low voltage side of the transformer .

I'm Asumming That if I Control SD with microcontroller to shut down the inverter before apply the triac 's tap. Since it is a full bridge I may use  the mosfet body  diode as rectifiers .

Any Input is appreciated.

2

Automation, Controls, Inverters, MPPT, etc / OzInverter with 3 Stages Charging System for 12v,24v,36v and 48VDC & Transfer.

« Last post by Sandramar on May 06, 2024, 10:27:45 am »

Hello,

I'm developing a Firmware in order to control a Triac at high votage side of the transformer with a charging tap .
In my case is  a 90vac tap  Relay switched when Mains are present. Transformer high voltage side is (Neutral,90vac and 120vac). In tention is use Body Diode of Mosfets as full wave rectifier.
Control board will follow votage 3 stage profile depending on voltage selected ( of course battery and transformer must match)
Before switch to "charging" state when mains are present , I'm asured that Inverter is powered down ( using SD) .
Questions :
1-There is a 20k resistor across Gate/source on OzInverter ... When shut down this resistor would be held the mosfet at the ground potential ?
2-The feedback Transformer which connected VFB , May use a 0.5 VA 14vac ?  I want to incorporate a smallest transformer there .

Any comment/suggestion would be highly Apreciated

SandraMar

3

Weather / Re: Been about a year

« Last post by bj on February 11, 2024, 05:03:39 am »

   We did finally get a bit of snow, (about 2 inches).
As we type away, supposed to be above freezing the next couple of days, then back to more seasonal.
   Longer range, they are expecting dry.  Province is expanding firefighting capabilities.  Last year was a record
for acres of forest burned.  (some fires still burning).
   In general, this area used to have all planting of crops done by May 24th long weekend.  Now the ones that
are planting 2 to 3 weeks earlier are doing much better.   My land renter did so, and got 150 bushel per acre of oats.
   All we can do is try to adapt.
bj

4

Weather / Re: Been about a year

« Last post by Wolvenar on February 10, 2024, 07:50:17 pm »

We are still warm here and basically no snow. I just put a water pump in the truck Jan 30th in a tee shirt in the driveway at +53F. Normally about then we are in a cold snap and will not have seen above 0F sometimes not above -20F for weeks, and would not for weeks more. It's still in the +40f range. We are quickly exiting the time period we could see negative temps this year. I'm a bit worried that without the normal weeks of melting and warm up we will see temps from August by June.
Not wanting to guess where August might bring us. But this is not anything this area has not seen, we have had this but its been a few generations.

5

Users Projects / Re: Off grid water heating project

« Last post by Wolvenar on January 29, 2024, 07:26:03 am »

Wouldn't an MPPT accomplish what your trying for here, or am I missing something?

6

Weather / Re: Been about a year

« Last post by bj on January 18, 2024, 05:17:28 am »

  Hi Wolv
No arguments from me on the lack of snow.  Haven't had to clear snow at all this winter.
Did eventually pay for the warm temps though.  Had lows in the -40 range for about 4 days, but starting to ease up now.
  Stay warm and happy.
BJ

7

Weather / Re: Been about a year

« Last post by Wolvenar on January 16, 2024, 04:34:47 pm »

We had a no snow Christmas here this year. No complaints from me.
It has been relatively warm even after wengot a snow cover this month, and as usual the weather guessers are treating it like it's the end of the world because we hit -23f for a few hours one night. That's warm for this time of the year here. Oh well media does what they do best, spread fear.
Merry belated Christmas to everyone.

8

Weather / Re: Been about a year

« Last post by bj on December 23, 2023, 06:40:46 am »

   hello David
Made that 75 mark as well this year.
Weather here unusual this year, almost a brown Christmas, and temps hovering around the freezing mark
during the day.  Long range says more of the same.
   Wishing you and yours,  as well as everybody here a Great New Years for 2024.
BJ

9

Weather / Re: Been about a year

« Last post by David HK on December 22, 2023, 04:44:12 pm »

Its been another year!

It's now Saturday 23rd December 2023!

And its damn cold here in Hong Kong.

Just a mere 8.77 degrees Celsius.

I trust anyone reading this note is as well as can be, and the weather is more hospitable wherever you are.

I made it to my 75th birthday! This is a great surprise.

Greetings to all.

David

10

Product Support / The dreaded Rifa smoke maker

« Last post by OTG on December 03, 2023, 06:22:57 am »

I recently scored an old 80's Bamix stick blender for $5 (Swiss made, barely used/like new - based in "Straya" 240V AC, 50Hz).

Got it home, put it under a mild load to test and seconds later... POOF, it let the smoke out - a stinky black haze shooting out from around the toggle switch!

Miffed/perplexed, I cracked the lid, and per the pictures, I now know of the infamous smoking Rifa's...

Bamix use an insulated (no earth) AC motor (the two yellow wires go straight to it) with a simple dial based toggle switch (two speeds + off). It seems this Rifa safety cap sits parallel between the power cord/switch and motor as a mains filter (that's my best guess anyways, if you know better, please do enlighten me)?

I'm keen to replace the cap, but I could do with a hand sourcing a suitable replacement:

This is the closest direct replacement I could find, but it's a bit rich for me and I'd prefer to avoid smoke-bomb caps - https://www.ebay.com.au/itm/181228603755

And I googled for an suitable Polyester alternative, but nothing looked to fit the bill.

So, if anybody can suggest a suitable replacement (preferably poly & cheap, must have 25mm long legs) that would be most appreciated.

Thanks y'all!

Original specs as follows (per pictures):

Rifa 40/085/56
PME 271 Y 522
CMV (written sideways - illegible)

0.022uF (b) Y

250V~MP
for 10 MHz

And, a bunch of safety labels... DVE 560-7 {S}LD2 (S)(N)

19mm Wide x 13mm Tall x 7mm Thick
25mm legs (needed to wrap it behind the board/ft in handle)