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Registered Member #3925
Joined: Fri Jun 03 2011, 10:50AM
Location:
Posts: 121
Patrick wrote ...
alf wrote ...
right, could i put the transistor in oil to cool it?
Dont bother. Waste of time, difficult to replace when thay blow.
right, i have installed the cpu cooler, using the part which it bolted onto from the old motherboard, and 3 2-pence coins lol and it works very well, there is heatsinking on the front (although not deliberate) as well, so now i can run the fbt continuously, or atleast a continuously as i dare to :P
alf wrote ...
im just using thermal grease, no insulator, the heat sink is at whatever voltage the drain is i guess, because i connect 1 side of the flyback to the heatsink, instead of to the drain pin.
Yes, this is the right way to go.
right, cool :D
alf wrote ...
btw does the secondary coil heat up too? or just the primary.
Yes, both heat up, as does the ferrite.
right, btw i broke the ferrite on one of my fbts, could i just glue it together again?
What voltage is your 555 at? Most are only good for 16 or 18 volts absolute max.
the 555 is operating at 5 volts, though i did try varying the supply voltage, and it made no difference as i turned it up to 15 volts, hmm.
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
alf wrote ...
Patrick wrote ...
Can you post a schematic?
hey,
yeah i just made one.... im ms paint lol so i apologize about the crappiness of it, but its pretty simple so it shouldnt be too difficult :P
here it is - thx. Alf.
I think you should reduce your R100 to R10 ohms, then increase your 555 timer to 10V. this may solve your problem, the gate Vgs threshold is 4 V, thats to close to the 5 volts your driving it with and the IRFP460 has 3nf of capactence so that and the 100R will slow the turn on, also .22 ohm on state resistance is going to act as a resistor, per the duty cycle, finnally try it with these changes and with out the cap across the primary.
Registered Member #3925
Joined: Fri Jun 03 2011, 10:50AM
Location:
Posts: 121
Patrick wrote ...
alf wrote ...
Patrick wrote ...
Can you post a schematic?
hey,
yeah i just made one.... im ms paint lol so i apologize about the crappiness of it, but its pretty simple so it shouldnt be too difficult :P
here it is - thx. Alf.
I think you should reduce your R100 to R10 ohms, then increase your 555 timer to 10V. this may solve your problem, the gate Vgs threshold is 4 V, thats to close to the 5 volts your driving it with and the IRFP460 has 3nf of capactence so that and the 100R will slow the turn on, also .22 ohm on state resistance is going to act as a resistor, per the duty cycle, finnally try it with these changes and with out the cap across the primary.
-Patrick
hey,
thanks! i will try that tomorrow, ok i will remove it :D the arc this guy gets is pretty awesome.
shouldnt his fbt have failed by then? O.o
i intend to wind my own ac fbt, but the problem is where do i get the wire... i could unwind it from the microwave oven transformer which i will be rewinding anyway, but this would be very time consuming i guess :(
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cooling flyback driver transistor?
