TURNS PER VOLT of a transformer winding

[compiler02]

Please I need help calculating the TURNS PER VOLT of a transformer winding. A formula from the data sheet i source form net: TPV = 1/(4.44*10-4*CA*flux density*AC frequency). And also the CORE AREA
EXAMPLE OF TPV FORMULA ABOVE
120va inverter using a 12volt automobile battery as the input and need 230volts as the output. to find the TPV, I need to know the 'CORE AREA' which is given as = 1.152*square root of 20*10 = 18 sq.cm, therefore:
TPV = 1/(4.44*10-4*18*1.3*50) = 1.96
MY CONFUSION IS I REALLY DON'T GET IT HOW COMES ABOUT THE RESULT OF THIS CALCULATION {CORE AREA = 18 } AND {TPV = 1.96} WHICH IS TOTALLY FAR DIFFERENT FROM MY CALCULATED RESULT.
Please help me out on the method used in concluding to the above result. THANKS.

 

[duke37]

Where does the formula come from?
What units does it use?
How do you get 18 sq cm from the numbers you supply?

2 TPV seems to be reasonable for a large 50 Hz transformer.

 

[compiler02]

Calculating turns per volt of transformer winding and core area

here is where i got the fomular from.
'

homemadecircuitsandschematics.blogspot.com/


How to Design Your Own Inverter Transformer
Posted by hitman

Designing an inverter transformer can be a complex affair. However, using the various formulas and by taking the help of one practical example shown here, the operations involved finally become very easy.


The present article explains through a practical example the process of applying the various formulas for making an inverter transformer. The various formulas required for designing a transformer has been already discussed in one my previous articles.

Designing an Inverter Transformer with the Help of a Practical Example

An inverter is your personal power house, able to transform any high current DC source into readily usable AC power, quite similar to the power received from your house outlets. Although inverters are extensively available in the market today, but designing your own customized inverter unit can make you overwhelmingly satisfied and moreover it's great fun.
At Bright Hub I have already published many inverter circuit diagram, ranging from simple to sophisticated sine wave and modified sine wave designs. However folks keep on asking me regarding formulas that can be easily used for designing a inverter transformer. The popular demand inspired me to publish one such article dealing comprehensively with transformer design calculations.

Although the explanation and the content was up to the mark, quite disappointingly many of you just failed to grasp the procedure. This prompted me to write this article which includes one example thoroughly illustrating how to use and apply the various steps and formulas while designing your own transformer. Let’s quickly study the following attached example:
Suppose you want to design an inverter transformer for a 120 VA inverter using a 12 Volt automobile battery as the input and need 230 Volts as the output. Now, simply dividing 120 by 12 gives 10 Amps, this becomes the required secondary current.

Primary Voltage = 230 Volts,
Secondary Current (Output Current) = 10 Amps.
Secondary Voltage (Output Voltage) = 12-0-12 volts, that is equal to 24 volts.
Output Frequency = 50 Hz
First we need to find the core area CA = 1.152 ×√ 24 × 10 = 18 sq.cm
We select CRGO as the core material.
Calculating Turns per Volt TPV = 1 / (4.44 × 10-4 ×18 × 1.3 × 50) = 1.96
Calculating Primary Current = (24 × 10) / (230 × 0.9) = 1.15 Amps,
By matching the above current in Table A we get the approximate Primary copper wire thickness = 21 SWG.
Therefore the Number of Turns for the primary winding is calculated as = 1.96 × 230 = 450
Next, Primary Winding Area becomes = 450 / 137 (from Table A) = 3.27 sq.cm.
Now, the required secondary current is 10 Amps, therefore from Table A we match an equivalent thickness of copper wire = 12 SWG.
Calculating Secondary Number of Turns = 1.04 (1.96 × 24) = 49.
Calculating Secondary Winding Area = 49 / 12.8 (From Table A) = 3.8 Sq.cm.
Therefore, the Total Winding Area Comes to = (3.27 + 3.8) × 1.3 (insulation area added 30%) = 9 sq.cm.

Calculating Gross Area we get = 18 / 0.9 = 20 sq.cm.
Next, the Tongue Width becomes = √20 = 4.47 cm.
Consulting Table B yet again through the above value we finalize the core type to be 6 (E/I) approximately.
Finally the Stack is calculated as = 20 / 4.47 = 4.47 cm


Thanks, for helping me out.

 

[masood.alvi]

Sir
I want 65_0_65 v 10 ampre transformer with 240v input
How turn in both side.

 

[Minder]

If you want a balanced centre tapped secondary, it should be wound Bifilar.
The easiest to add a winding on is an existing Toroidal type with the correct primary already wound, the typical T/V is around 2t/v this can be done by an empirical test of 1/2 dozen test winding's or so.
The basic transformer should have the VA required for your load. and the winding have the rated guage for the current you anticipate.
M.

 

[masood.alvi]

Calculating turns per volt of transformer winding and core area

here is where i got the fomular from.
'

homemadecircuitsandschematics.blogspot.com/


How to Design Your Own Inverter Transformer
Posted by hitman

Designing an inverter transformer can be a complex affair. However, using the various formulas and by taking the help of one practical example shown here, the operations involved finally become very easy.


The present article explains through a practical example the process of applying the various formulas for making an inverter transformer. The various formulas required for designing a transformer has been already discussed in one my previous articles.

Designing an Inverter Transformer with the Help of a Practical Example

An inverter is your personal power house, able to transform any high current DC source into readily usable AC power, quite similar to the power received from your house outlets. Although inverters are extensively available in the market today, but designing your own customized inverter unit can make you overwhelmingly satisfied and moreover it's great fun.
At Bright Hub I have already published many inverter circuit diagram, ranging from simple to sophisticated sine wave and modified sine wave designs. However folks keep on asking me regarding formulas that can be easily used for designing a inverter transformer. The popular demand inspired me to publish one such article dealing comprehensively with transformer design calculations.

Although the explanation and the content was up to the mark, quite disappointingly many of you just failed to grasp the procedure. This prompted me to write this article which includes one example thoroughly illustrating how to use and apply the various steps and formulas while designing your own transformer. Let’s quickly study the following attached example:
Suppose you want to design an inverter transformer for a 120 VA inverter using a 12 Volt automobile battery as the input and need 230 Volts as the output. Now, simply dividing 120 by 12 gives 10 Amps, this becomes the required secondary current.

Primary Voltage = 230 Volts,
Secondary Current (Output Current) = 10 Amps.
Secondary Voltage (Output Voltage) = 12-0-12 volts, that is equal to 24 volts.
Output Frequency = 50 Hz
First we need to find the core area CA = 1.152 ×√ 24 × 10 = 18 sq.cm
We select CRGO as the core material.
Calculating Turns per Volt TPV = 1 / (4.44 × 10-4 ×18 × 1.3 × 50) = 1.96
Calculating Primary Current = (24 × 10) / (230 × 0.9) = 1.15 Amps,
By matching the above current in Table A we get the approximate Primary copper wire thickness = 21 SWG.
Therefore the Number of Turns for the primary winding is calculated as = 1.96 × 230 = 450
Next, Primary Winding Area becomes = 450 / 137 (from Table A) = 3.27 sq.cm.
Now, the required secondary current is 10 Amps, therefore from Table A we match an equivalent thickness of copper wire = 12 SWG.
Calculating Secondary Number of Turns = 1.04 (1.96 × 24) = 49.
Calculating Secondary Winding Area = 49 / 12.8 (From Table A) = 3.8 Sq.cm.
Therefore, the Total Winding Area Comes to = (3.27 + 3.8) × 1.3 (insulation area added 30%) = 9 sq.cm.

Calculating Gross Area we get = 18 / 0.9 = 20 sq.cm.
Next, the Tongue Width becomes = √20 = 4.47 cm.
Consulting Table B yet again through the above value we finalize the core type to be 6 (E/I) approximately.
Finally the Stack is calculated as = 20 / 4.47 = 4.47 cm


Thanks, for helping me out.

Sir secondry no of turn 1.04 from where it comex
That may be 1.96 x 24 =47.04

 

[Colin Mitchell]

Simply wind 20 turns using any gauge wire and measure the voltage.
This will take 10 minutes and require no electrical skill what-so-ever.
This is what I have done for 40 years as I have no electrical skills at all.

 

[masood.alvi]

But at what place i turn

 

[Colin Mitchell]

At any place, either over the primary or secondary.

 

[Minder]

What is the form or type of the transformer, EI or Toroidal etc? Is this an existing transformer or are you constructing something, IOW do you already have the core, if so does it have any present windings?
And if so, what are they?
M.

 

[masood.alvi]

I will use E I core
Perhaps it will 8 No core crgo but i am turns in primary and secondary
What will guage of wires

 

[masood.alvi]

What will the turns in each side ?
Guage of wires for input and output
I will use E I type core of 8 No crgo core.
Thanks

 

[Colin Mitchell]

Basically you wind the primary until you fill half the volume.
The turns per volt depends on the VA of the core.
You find the turns-per-volt from another identical core. You then multiply this by the supply voltage.
Now you have the number of turns for the primary.
Mic the primary wire and use the same gauge.
This is how you work it out without using any skill. Because I have no skills what-so-ever.

 

[masood.alvi]

Sir can any one will veryfy my trasformer calculation
In put vol .230v
Output volt 65--0--65 at 10 amp
Core area=41.54
Tpv= 8.02
Input current=6.28
Prim.turns=1845
Sec.turns=1084
Area of primary=85.81
Area of secondary=84.68
Total winding area=170.49
Gross area=46.15
Tongie=6.79
Stack=6.80.
Values are in cm.
But in table b it is tongue width 5.08 last my tongu width is 6.79 how can i choose core.?
Thanks

 

[Colin Mitchell]

The TPV is too high for VA.

 

[masood.alvi]

Tpv=1/4.44*10.4*41.54*1.3*50=8.02

 

[Colin Mitchell]

Ok. If you think the TPV should be 8.02, go and wind the transformer yourself. Don't bother asking us.

 

[Colin Mitchell]

If you want to know how to find the turns per volt, I will tell you.
No book, magazine or text book has ever told you this before.
You wind 8 turns per volt and assemble the transformer and connect the supply.
Feel the temperature after 10 minutes.
Remove 50 turns and repeat.
Keep doing this and eventually a point will come when the winding gets very hot.
The TPV is too low. Add more turns.
This is how it was done in the first place.

 

[duke37]

A excellent source of information on transformer design and manufacture is
ludens.cl/electron/trafos.html
I suggest you look at this. He gives a table of wire diameters, I believe that the current density can be 3A/mm^2.

Chose a core of a size to give the VA you want. Work out the turns to get the appropriate flux.
A rough rule of thumb is that 8T/V can be used for a one inch square core at 50Hz. The core can be made thicker by adding more laminations but this necessitates longer wires so the transformer will be a litle less efficient than one with a square core.
Take half the area for the primary and half for the secondary. Find the turns/Volt and work out the wire thickness to fill the area. It depends on how good a winder you are but you should be able to get a packing density of 80%. This will give the permitted current.
Repeat until you are satisfied.
From the wire table the length of the wire and the weight can be obtained.

Alternatively, take the secondary off an existing transformer, counting the turns, and replace with a winding to give the voltage required.

 

[masood.alvi]

I am not satisfied yours answers
Thanks