Home
JAQForum Ver 19.8.18
Log In or Join  
Active Topics
Local Time 12:35 22 Aug 2019 Privacy Policy
Jump to

Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.

Forum Index : Electronics : Kent’s 10KW Inverter

     Page 3 of 3    
Author Message
BenandAmber
Guru

Joined: 16/02/2019
Location: United States
Posts: 727
Posted: 02:06am 14 Aug 2019
Copy link to clipboard 

Make it is exactly how you want it and then epoxy it and it might last you the rest of your life

Warp speed will tell you exactly how to make it the perfect toroid

I can only look dream and drool
Edited 2019-08-14 12:07 by BenandAmber
 
tinyt
Guru

Joined: 12/11/2017
Location: United States
Posts: 372
Posted: 02:51am 14 Aug 2019
Copy link to clipboard 

Looks like the 240v winding is only one layer (2 in hand). You might not have to un-wind it.

It is easy to split it into two 120V windings by looking for the midpoint of the existing winding. Somewhere here is how I did mine (Posted: 03:55am 04 Jun 2018).

Then you can just add to each of the two separated windings more turns to lower the flux density.
Edited 2019-08-14 12:53 by tinyt
 
Warpspeed
Guru

Joined: 09/08/2007
Location: Australia
Posts: 2670
Posted: 03:05am 14 Aug 2019
Copy link to clipboard 

Next step, measure the exact dimensions of the bare core now that you can actually see it, and count the turns that are already on there, and measure the wire diameter.

Once we know exactly what is there, we can decide what to do.
Cheers, Tony.
 
kentfielddude
Regular Member

Joined: 09/05/2019
Location: United States
Posts: 78
Posted: 10:40pm 17 Aug 2019
Copy link to clipboard 

OD -    280mm
ID -    140mm
Height -120mm

Turns: 66
Wire size - Two 4.6mm diameter wire
Edited 2019-08-18 08:45 by kentfielddude
 
Warpspeed
Guru

Joined: 09/08/2007
Location: Australia
Posts: 2670
Posted: 11:51pm 17 Aug 2019
Copy link to clipboard 

Thanks Kent, it was the 120mm height I was missing.

O/k, going to our handy flux calculator:
https://daycounter.com/Calculators/Max-Flux-Density-Calculator.phtml

For the existing secondary we have now, enter the following:

Voltage   240
Frequency 0.0006 Mhz
Turns     66
Core area 108cm sq  (90mm x 120mm)

Flux = 1,264 gauss, (or 1.264 Teslas in metric)

We really need to reduce the flux density to 1.0 Teslas or less, to reduce the idling current and the initial inrush current.

Not surprisingly, the primary and secondary are wound from the same 4.6mm diameter wire, and we know that the original secondary has wire length enough for 25 turns.

Now suppose we add 25 turns to our existing 66 turn secondary, making 91 turns.

Voltage   240
Frequency 0.00006 Mhz
Turns     91
Core      108cm sq

Flux = 0.916 Teslas.

That should work out pretty well, but we can test it first and see how well.

Add 25 turns to the existing winding using any convenient thin plastic insulated wire that you have there. Connect that up to the 220v supply, and measure the idling current.

We have reduced the flux density by 66/91 or to to about 73% of what it was.
But the idling current will fall by a much greater amount than that, to probably less than 50% of the original 100 or so watts of idling power.
Try it and see  
Cheers, Tony.
 
kentfielddude
Regular Member

Joined: 09/05/2019
Location: United States
Posts: 78
Posted: 12:21am 18 Aug 2019
Copy link to clipboard 

Will this be suitable to use for testing? I don't have a 220v source readily available
Edited 2019-08-18 10:23 by kentfielddude
 
Warpspeed
Guru

Joined: 09/08/2007
Location: Australia
Posts: 2670
Posted: 12:31am 18 Aug 2019
Copy link to clipboard 

Yes, that will be fine.
I actually have one of those transformes myself.
Cheers, Tony.
 
tinyt
Guru

Joined: 12/11/2017
Location: United States
Posts: 372
Posted: 01:35am 18 Aug 2019
Copy link to clipboard 

Almost all residential wirings here have 220VAC (black wires) at the power service entrance. Between the two black wires is 220VAC. Inside the circuit breaker box, there are neutral wires and between these neutral wires and each of the black wires is 110VAC. The neutral is usually white and the bare wires are also at neutral.

At the circuit breaker box, they connect the 220V loads (AC, Electric Range) to 220VAC. They split the regular 110VAC outlets and 110VAC lighting between the two 220VAC black wires and neutral. The 110VAC outlet will have one of its terminal connected to a white wire and the other to a black wire(live, if wired to code the shorter slot of the socket).

Because of the 110VAC loading split, it is possible that one 110VAC outlet will be served by one of the black wire and another 110VAC outlet served by the other black wire.

So if you have some insulated wires and a multimeter, you can look for this pair of outlets and have 220VAC for your testing, no need for a doubler transformer. I actually, installed a 220VAC outlet in one of our rooms using this method.
Edited 2019-08-18 11:52 by tinyt
 
     Page 3 of 3    


To reply to this topic, you need to log in.

© JAQ Software 2019