Transformer winding advise needed!!!

[Clarkdale44]

Hello

Winding a transformer for CFL circuit (Using flyback transformer's core)

I just need to ask if i were to wind the coil on flyback core, how it should be done? There are two sides on flyback core, should i just wide it like always wire over wire (primary, feedback and secondary)? or there is some other method for winding coil on flyback core? which one will be more efficient for the circuit?

There are two circuits below, please let me know if the method of winding is same for the both circuits or not, also if you see any flaw in it then let me know that as well.

Thank you i appreciate a lot for your replies...
This is my last question regarding any CFL related stuff...

**broken link removed** **broken link removed**

 

[Nigel Goodwin]

Assuming it's the usual square shaped core used for LOPTX's, they normally wind the EHT on one side, and the other windings on the other side - I would imagine it would make sense to do the same here - keep the high and low voltages separate.

It would also make it trivial to add or subtract windings from the secondary.

 

[Clarkdale44]

Assuming it's the usual square shaped core used for LOPTX's, they normally wind the EHT on one side, and the other windings on the other side - I would imagine it would make sense to do the same here - keep the high and low voltages separate.

It would also make it trivial to add or subtract windings from the secondary.

Forgot to add image, the core i have is exactly like this one. So i just have to wind primary and feedback on one side and secondary on the other.. is that right???

 

[Nigel Goodwin]

Sort of - but you've got the winding on the wrong part of the core

The windings go over the gaps - so you can slide the core through (and clamp it up) after winding the coils.

 

[Clarkdale44]

Sort of - but you've got the winding on the wrong part of the core

The windings go over the gaps - so you can slide the core through (and clamp it up) after winding the coils.

Image is just for reference, that's not mine....

 

[dr pepper]

It would probably still work as the pic, just slightly higher losses as the magnetic path has changed.
Originallythe lopty probably had an air gap, there would have been spacer between where the halfs meet, if your winding a transformer I think your better without them, if your winding a flyback then they will improve performance done right.
As per Nige's comments wind the primary on one long side and the sec on the other long side, you could wind them both on the same side as per the original lopty would have been, however winding by hand instead of machine it would be slightly more efficient to wind one each side, as the coils would be closer to the core material.

 

[Nigel Goodwin]

As per Nige's comments wind the primary on one long side and the sec on the other long side, you could wind them both on the same side as per the original lopty would have been.

It probably wouldn't have been, as I said earlier it was normal to have the EHT one side, and the low voltage windings the other side - there were even repair kits for some older transformers, where you could replace just the EHT winding.

 

[dr pepper]

I see what you mean now, older ones with ac outputs did have a coil each end.
Later ones are all one piece.
But you'd know that a lot better than I as you've probably changed 300 or so.

 

[Nigel Goodwin]

I see what you mean now, older ones with ac outputs did have a coil each end.
Later ones are all one piece.

They also tended to incorporate the rectifiers in the transformers later on, 'diode-split' was a popular technique, using inter-winding capacitance rather than physical capacitors.

But you'd know that a lot better than I as you've probably changed 300 or so.

Not as few as that!

 

[dr pepper]

I opened one up a while back, it had all the lt stuff at the base, and as you say a bit of secondary, a diode another bit of secondary, another diode and so on, industrial h.t. stuff is similar only they solder diodes across tags on the sode of the trans so you can replace them.

 

[Nigel Goodwin]

I opened one up a while back, it had all the lt stuff at the base, and as you say a bit of secondary, a diode another bit of secondary, another diode and so on, industrial h.t. stuff is similar only they solder diodes across tags on the sode of the trans so you can replace them.

The most common failure (apparently) in EHT triplers was the capacitors rather than the diodes, so by moving the diodes inside the tx and utilising inter-winding capacitance as the capacitors it improved reliability. Plus of course it removed an extra HV connection from transformer to tripler.

 

[chemelec]

Compact Florescent Bulbs also have Filaments that heat the Mercury in them.
If you Don't use these Filaments, You won't get the Full Brightness from the bulb.

Your Circuit Only Supplies the High Voltage, but No Filament Heaters.

Here is a Typical 110 VAC Schematic, Plus a Close-up Picture of one of these Filaments inside the bulb.
http://chemelec.com/Projects/Compact/Compact-Lights.htm

 

[Nigel Goodwin]

Compact Florescent Bulbs also have Filaments that heat the Mercury in them.
If you Don't use these Filaments, You won't get the Full Brightness from the bulb.

Poor light anyway

Use LED's instead, more light for only half the power - I'm currently in the process of replacing all my lights with LED ones.

 

[Clarkdale44]

Poor light anyway

Use LED's instead, more light for only half the power - I'm currently in the process of replacing all my lights with LED ones.

You talking about those 1w led's? Yeah i thought about using those but they are quite expensive unless i buy them in bulk. Also i have quite a few old fluorescent tubes from damaged cfl, so for now i just wanna reuse them however i can. I am gonna make high power led lamp in future once i run out of cfls which i have currently on hand.
Thanks for all your help...

 

[Clarkdale44]

Compact Florescent Bulbs also have Filaments that heat the Mercury in them.
If you Don't use these Filaments, You won't get the Full Brightness from the bulb.

Your Circuit Only Supplies the High Voltage, but No Filament Heaters.

Here is a Typical 110 VAC Schematic, Plus a Close-up Picture of one of these Filaments inside the bulb.
http://chemelec.com/Projects/Compact/Compact-Lights.htm

Well, this is not actually a CFL circuit but a simple fluorescent inverter. I am trying to drive a fluorescent tube salvaged from an old CFL using 12v dc, if possible please give me a circuit where there are filament heaters as well, i will appreciate that. The circuit you have provided working on AC while mine works on DC.

 

[dr pepper]

You can use a cfl as a ccfl I have done so a few times, in other words you dont have to use the tubes heaters, not sure whether its brightness is affected or not, you will still be able to make a decent light from it.
The heaters aid ionization of the gas within the tube, if your circuit design produces high voltage spikes that'll do the same job.
In a cfl theres a cap across the heater connections, this is tuned to the switching freq of the lamps inverter, not very practical with a simple oscillator like you'll be building.
For a couple of people I have put togther a fuji disposeable camera circuit that powers a cfl, they are quite good, if you can get your hands on an old scanner, one with a tube not leds they usually have a 12v to fluorescent tube driver that can be used to drive a cfl, or ccfl.
Leds are more efficient than fluorescents, the latter can be softer light, for reading and working leds are great.

 

[chemelec]

You talking about those 1w led's? Yeah i thought about using those but they are quite expensive unless i buy them in bulk. Also i have quite a few old fluorescent tubes from damaged cfl, so for now i just wanna reuse them however i can. I am gonna make high power led lamp in future once i run out of cfls which i have currently on hand.
Thanks for all your help...

"Goldmine Electronics" has some Quite Reasonable Priced:
1 watt, 3 watt and 10 Watt Bright White LED's.
https://www.goldmine-elec-products.com/

 

[chemelec]

Well, this is not actually a CFL circuit but a simple fluorescent inverter. I am trying to drive a fluorescent tube salvaged from an old CFL using 12v dc, if possible please give me a circuit where there are filament heaters as well, i will appreciate that. The circuit you have provided working on AC while mine works on DC.

This is a CFL.

 

[Colin]

Both circuits above are mine and work perfectly with a fluorescent tube or CFL.
You don't need heaters for a CFL. The only reason why heaters are included is because many of the CFL circuits don;t produce a high starting voltage and the tube will not strike.
"If you Don't use these Filaments, You won't get the Full Brightness from the bulb."
This is entirely untrue. I have explained the reason for the heaters.
What everyone has failed to point out is the fact that you don't need a full magnetic circuit is you are not over-driving the core.
That's why the cores used in my circuits are round ferrite rods.
There is absolutely no reason why the primary, secondary, over-wind, feedback windings cannot be placed on top of each other. It adds to the tightness of the transformer.
"Originally the lopt probably had an air gap, there would have been a spacer between where the halfs meet. If you're winding a transformer, I think you're better without them, if you're winding a flyback then they will improve performance done right."
This is false.
You MUST have an air gap in the magnetic circuit because the primary has a DC component and this will saturate or partially saturate the core before you start to drive the circuit.