How can i solve the myth of Flyback transformer winding ?

[itsashutamar]

Hi
Experts i found something exciting i dont know how its possible recently i design "Flyback Isolated DC-DC Converter" and its FBT (Flyback Transformer) specs below
turns and wire gauge details (i hope it will to understand it )
core used is EE25/EPC25

when i connect this tf with my "Flyback Isolated DC-DC Converter" without considering the starting and ending point it work

s fine without heating so whats the plz help me to solve this myth

1. As per my understanding (can be wrong) but is it really matter that while connecting wire of input and load then the result is same

2. as i tested it and working fine

one problem is that is heating the components and auz widing giving 60v as same input volt is applied at primary whats thar guys
this pics my professor send me to explain

induction details

[6v6gt]

@itsashutamar

when i connect this tf with my "Flyback Isolated DC-DC Converter" without considering the starting and ending point it works fine without heating

What does this DC-DC converter look like ? Somthing like the first schematic here ? : Loneoceans Laboratories - Flyback Driver Circuits

This isn't very clear. Can you explain what you now appear to say is a heating effect ?

@itsashutamar

one problem is that is heating the components and auz widing giving 60v as same input volt is applied at primary whats thar guys
this pics my professor send me to explain

[itsashutamar]

yes heating issue aux volt is 60v and plz tell me is it important to consider tf starting and end point

[6v6gt]

Again it is not clear but I think by the issue of tf (transformer) starting and end point, you mean the polarity of the windings, usually indicated by a dot on schematic diagrams.

It is important to respect this.

See also for example: https://www.electrical4u.com/transformer-polarity-test/

[itsashutamar]

but i test this im not facing any problem but heating is

[6v6gt]

I'm having difficulty understanding your problem description.
Anyway, if you are having problems with heating, it may be that you are driving the primary circuit with a frequency which is too low. If you have shorted one of the secondary coils, there will be also a heating effect.
This is anyway not my expert area. I suggest you include a schematic diagram in this thread and maybe someone else can help.

[TomGeorge]

Hi,

An image of a hand drawn schematic will be fine, include ALL power supplies, component names and pin labels.

From your images, it looks like this is part of a larger circuit.
Have you prototyped first on its own before adding to a project?

Where do you get the design information?
Your design sheet doesn't even start at the beginning of the coil, is it a tapped single winding?

Thanks.. Tom...

[johnerrington]

@TomGeorge

From your images, it looks like this is part of a larger circuit.

As Tom says we need a schematic

How to make a schematic you can post.

When you submit a question on the forum you will usually need to add a schematic (circuit diagram). The tutorial that follows will explain some ways to create a useful image; however lets start by explaining how to add the image to your post. Its easy. Having created the image all you need to do is : Save the image somewhere convenient - maybe your desktop Start your post, and place the cursor (insertion point) where you want the image to be shown; [upload image to forum] 3: click th…

[DVDdoug]

I'm not an expert on transformers but you probably need more turns for more inductance, or perhaps higher switching frequency.

If you are studying transformers I assume you understand inductive reactance and resistance. The wire resistance will be very low so if the there is not enough inductance, or it the frequency is too low you'll get excess current and heating.

[frpr666]

I like this article "flyback converters for dummies"; url below. There is "An Inductor test bench" described where you can check the coil current by oscilloscope under conditions close to the end application. If the inductance is too small or the switch on-time too long than the ferrite core may saturate and the current may increase sharply.
flayback converters for dummies

[itsashutamar]

Dear first of all thank you so much from my heart for reply I'm saying that when i connected flyback transformer output is fine everything is fine but i can able to find the problem that why its primary winding components getting heating up

[itsashutamar]

[itsashutamar]

here is the turns and wire gauge details

[6v6gt]

I see an oscilloscope in one of your pictures. Start by showing a trace taken at pin 6 of the uc3843 chip so the frequency and duty cycle are clear.

EDIT

Also measure the voltage at pin 7 (Vcc) of the uc3843

[itsashutamar]

its 30v

[6v6gt]

@itsashutamar

its 30v.

That has satisfactorily answered half of the questions I asked.

[itsashutamar]

okay

[6v6gt]

Does the uc3843 chip get warm ? Its maximum voltage is 28v, and you have said that you have measured 30v. The 10 ohm resistor in the auxilliary circuit (winding N2) looks very low to me. I could imagine that the uc3843 protection diodes are cutting in. You could measure the current. The chip itself needs less than 25mA on quick scanning of the data sheet.

[itsashutamar]

okay i will check

[TomGeorge]

Hi,
From.

uc3843.pdf (3.9 MB)

The UCx84x has a VCC supply voltage clamp of 34 V typical, but the absolute maximum value for VCC from a low-impedance source is 30 V.
For applications that have a higher input voltage than the recommended VCC voltage, place a resistor in series with VCC to increase the source impedance.

@6v6gt

The 10 ohm resistor in the auxilliary circuit (winding N2) looks very low to me.

Ditto

N2 may have too many turns.

Tom...