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"The tack-welders I've seen have the electrodes pressing the pieces together at the same moment the electrodes send current. Can you arrange to do the same thing with your pieces?"
Hmm. Thing is I don't have a high current switch to apply the high voltage from the bulk cap. I close the circuit...
Hello gents,
I'm trying to weld a thermocouple wire to a TO-220 tab. Anyone done it successfully?
I tried charging a 560 uF capacitor up to 400V, with one side electrically connected to the TO-220 tab, and the other, to the thermocouple wire, then touching the wire to the tab to get a big arc...
The increases losses, heatsink and magnetics size will not make a flyback the lowest cost solution. Especially not a discontinuous one.
Windings in big flyback transformers are very lossy due to the gap. You can't run them at high frequency. Which will make them even bigger.
Forward and...
"there are some perturbations around the middle point of every half wave - between the zero crossing and peak voltage"
- Is it a "fuzz"? Are you using unipolar modulation?
"the wave form has almost a trapezoid shape)"
- is it symmetric, both top and bottom? Or only one side?
- Are you...
Re: Two Transistor Forward converter suffers overly high magnetiing current.
With a very low leakage inductance transformer that also has a very high magnetizing inductance and thus very low open-circuit resonance (Lm & Cwinding + Coss), at turn off the voltage on the windings rises very slowly...
Burst mode frequencies are typically tunable to go from 100's to 1000's of Hz. Eye can't see that. Lots of LED systems do dimming by PWM'ing at a few 100 Hz.
Also, LED's don't go down very much in voltage as current is reduced, unlike a resistive load.
Lotsa folks use LLCs with PFC for LED's...
If your load current goes way down but the voltage doesn't, and if the input voltage is relatively fixed (i.e. PFC pre-regulated), an LLC will work great. You just have to use a largish leakage inductance (say 1/2-1/3rd of magnetizing L) and set the turns ratio so operating frequency at full...
Do I understand correctly you're looking to build a 1 kW flyback, 400V in, 57V out, 500 kHz?
Yikes.
I wouldn't build an LLC at 500 kHz and 1 kW.
Sorry I'm late to the party, but why a flyback instead of an LLC or full bridge?
Re: Two Transistor Forward converter suffers overly high magnetiing current.
Can you show the voltage across the primary in the last few cycles before that point?
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