cupoftea
Advanced Member level 5
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Hi,
We are doing a 130W Offline Two Transistor forward after a rect bridge input.
(Fsw=120kHz, vout=24v)
Vin is 100-373VDC.
We have chosen to use PQ26/20 ferrite cores from ferroxcube (3F3).
But our contractor has offered us, free of charge, a load of "lapped" PQ26/20 cores which he says are 3F3 equivalent.
Do you think we should take them?
The problem is, ayk, that if the supply is overloaded, when at max vin of 373V, then the duty cycle will go to
maximum for a few seconds (before overload timeout kicks in). During those few seconds, the lapped cores
will go into brick wall saturation, and the magic smoke will come.
So do you agree, that lapped cores are a no-no for our two transistor forward?
We are doing a 130W Offline Two Transistor forward after a rect bridge input.
(Fsw=120kHz, vout=24v)
Vin is 100-373VDC.
We have chosen to use PQ26/20 ferrite cores from ferroxcube (3F3).
But our contractor has offered us, free of charge, a load of "lapped" PQ26/20 cores which he says are 3F3 equivalent.
Do you think we should take them?
The problem is, ayk, that if the supply is overloaded, when at max vin of 373V, then the duty cycle will go to
maximum for a few seconds (before overload timeout kicks in). During those few seconds, the lapped cores
will go into brick wall saturation, and the magic smoke will come.
So do you agree, that lapped cores are a no-no for our two transistor forward?