Coilgun question.
Platinum, Sat Dec 31 2011, 02:51AMIf my coilgun uses an SCR, will I need a protective diode (Only ones I got is RU4Z,Y, can I put them in series? for more voltage) to obviously protect the circuit and all that?
SCR = BTW30-1000
Also I'm using rectified mains to charge it, 320v, yet caps are 420v 1510uF, will the coilgun be powerful.
My coil is a bunch of thick wire on a plastic spool taken from a Ferrite core of a 12v 32A PSU, it does not have many turns, does this matter?
Thanks. When I get the info I need I'm going to build it inside a shoebox ^^
I also have another coil, it has a bucket load of turns I used all of the windings off a CRT deflection coil, not very think wire, but who care.
Re: Coilgun question.
Platinum, Sat Dec 31 2011, 11:07PM
Just tested one of my coils without SCR, and it is terrible, the coil acts as a inductive resistor. ¬¬
Platinum, Sat Dec 31 2011, 11:07PM
Just tested one of my coils without SCR, and it is terrible, the coil acts as a inductive resistor. ¬¬
Re: Coilgun question.
Alex M, Thu Jan 05 2012, 09:19PM
If you are in the UK, which I see you are then get to maplins and ask for a spool of 24 SWG magnet wire. I did not take any wire off of the spool but just inserted a PVC pipe into the middle of the spool and I then discharged my capacitor bank into the two ends of the spool. It has quite a bit of force behind it!
I got the PVC pipe from wickes.
Alex M, Thu Jan 05 2012, 09:19PM
Platinum wrote ...
Just tested one of my coils without SCR, and it is terrible, the coil acts as a inductive resistor. ¬¬
Just tested one of my coils without SCR, and it is terrible, the coil acts as a inductive resistor. ¬¬
If you are in the UK, which I see you are then get to maplins and ask for a spool of 24 SWG magnet wire. I did not take any wire off of the spool but just inserted a PVC pipe into the middle of the spool and I then discharged my capacitor bank into the two ends of the spool. It has quite a bit of force behind it!
I got the PVC pipe from wickes.
Re: Coilgun question.
Saz43, Fri Jan 06 2012, 07:21PM
I hope this helps! Let us know how it goes.
Saz43, Fri Jan 06 2012, 07:21PM
Platinum wrote ...
If my coilgun uses an SCR, will I need a protective diode (Only ones I got is RU4Z,Y, can I put them in series? for more voltage) to obviously protect the circuit and all that?
If your coil is underdamped, you will need a protective diode (also known as a commutation diode). In order to determine if your coilgun is underdamped, enter your coil properties here and simulate your circuit here. If the capacitor voltage ever becomes negative, your coil is underdamped.If my coilgun uses an SCR, will I need a protective diode (Only ones I got is RU4Z,Y, can I put them in series? for more voltage) to obviously protect the circuit and all that?
wrote ...
SCR = BTW30-1000
This data sheet contains all of the information for your SCR, and was found with Google.SCR = BTW30-1000
wrote ...
Also I'm using rectified mains to charge it, 320v, yet caps are 420v 1510uF, will the coilgun be powerful.
The formula for energy (in Joules) stored in the capacitors is E = 0.5*C*V^2, where C = Capacitance and V = Voltage. Calculate that and compare to other coilguns with similar energy to find out what results you can expect.Also I'm using rectified mains to charge it, 320v, yet caps are 420v 1510uF, will the coilgun be powerful.
wrote ...
My coil is a bunch of thick wire on a plastic spool taken from a Ferrite core of a 12v 32A PSU, it does not have many turns, does this matter?
Magnetic force is proportional to coil turns and coil current, so you will need a significant number of turns. I made a simple guide to designing a coil here.My coil is a bunch of thick wire on a plastic spool taken from a Ferrite core of a 12v 32A PSU, it does not have many turns, does this matter?
I hope this helps! Let us know how it goes.
Re: Coilgun question.
Platinum, Fri Jan 06 2012, 09:36PM
My SCR failed after a few runs of the coilgun.
Platinum, Fri Jan 06 2012, 09:36PM
My SCR failed after a few runs of the coilgun.
Re: Coilgun question.
Pinkamena, Wed Jan 11 2012, 11:07PM
That could be because you surpassed the maximum surge current of your SCR. It was fairly low (210A), and since you told us your coil did not have many turns, I suspect the current shot through the roof. You'll need more turns, giving the coil higher inductance and resistance. This will slow down the discharge, producing less current. It will also give a nice, long and steady magnetic field, that'll give you higher efficiency than a short high-powered pulse.
Pinkamena, Wed Jan 11 2012, 11:07PM
That could be because you surpassed the maximum surge current of your SCR. It was fairly low (210A), and since you told us your coil did not have many turns, I suspect the current shot through the roof. You'll need more turns, giving the coil higher inductance and resistance. This will slow down the discharge, producing less current. It will also give a nice, long and steady magnetic field, that'll give you higher efficiency than a short high-powered pulse.
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