Virus Posted August 12, 2011 Report Posted August 12, 2011 Hi there,I have built the attached circuit found on the web, purpose of the circuit is to develop a electromagnetic pulse in an air coil using 240v AC, and it is not working. I can Quote
Hero999 Posted August 12, 2011 Report Posted August 12, 2011 It' good you haven't managed to turn the triac on given that it would probably blow up as it will be short circuited every half a cycle via the diode.Why all the complexity? Surely it's easier to just use a changeover switch so the capacitor charges when it's in one position and discharges when it's in the other position? Quote
Virus Posted August 13, 2011 Author Report Posted August 13, 2011 Hi Hero999Yep I see now, would this circuit work beter ?What about the value of R1 for the led and protection diode for the back emf on C1.Any other suggestions that might help?Thanks, much appreciated!Virus ;DMag_240v.PDF Quote
Hero999 Posted August 13, 2011 Report Posted August 13, 2011 You don't need a double pole switch, SPDT will do.What's the resistance of the 2.7mH coil?The peak current will be near 200A, if it's nothing which can cause the switch contacts to weld.You should also limit the charging current otherwise the bridge rectifier will be killed as welll as the switch. Quote
Virus Posted August 13, 2011 Author Report Posted August 13, 2011 Hero999I think because of the high currents is the reason why the circuit was designed with the triac and scr doing all the work ? The coil resistance is 0.6 ohm.How can I limit the charging current in the circuit?Virus ;D Quote
Virus Posted August 14, 2011 Author Report Posted August 14, 2011 Hi I realized that D2 was at the wrong place, I have redrawn the circuit and it should work now as attached, can you please confirm the component values, (I will replace the Triac as it is probably fried,)Now back to the first questions in this post,Question :What resistor values must I use for the gates on the BTA08-600 and the 2N6509 respectively to get them to fully switch on?What amperage value switch should I use as a toggle switch?I also know that there is a diode missing that will protect the capacitor from the back EMF, will D3 do the job in this circuit?Any suggestions to improve this circuit?ThanksVirus Mag_240v_2.PDF Quote
Hero999 Posted August 14, 2011 Report Posted August 14, 2011 The TRIAC still won't turn on because the the switch is just connecting the gate to A1.Why use a TRIAC when it's only being used as an SCR as a diode is connected in series with it? You should just replace it with an SCR. A resistor can be used to limit the charging current.The switch hardly passes any current because it mostly goes thought the TRIAC and SCR. Quote
Virus Posted August 16, 2011 Author Report Posted August 16, 2011 Hi Is this circuit layout beter!Can you please take time look at this circuit and give me some contructive advice.Any one please ?Virrus ;DMag_pulsar_240v_3.PDF Quote
Hero999 Posted August 17, 2011 Report Posted August 17, 2011 The TRIAC will now turn on but you've stlll not paid any attention to the issues raised in my previous posts. Quote
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