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Re: High Power Solid State Tesla Coil - Successful Test
Original poster: "Darren Freeman by way of Terry Fritz <twftesla-at-qwest-dot-net>" <free0076-at-flinders.edu.au>
At 02:57 PM 05/07/2002, you wrote:
>Original poster: "Daniel McCauley by way of Terry Fritz
>Just finished all my "resisitive load" tests on my new high power solid
>state tesla coil driver and decided to go with a quick first time test with
>the primary connected.
I'm also working on a solid state driver for my coil.. It's been a very
long time in the works due to limited funds / equipment.
I don't tend to post on the pupman list coz there's so friggin' many posts
each day =)
>Darn, didn't have enough wire, but managed to get 10 turns of 10 AWG wire on
Old 50 ohm coax seems to work well, using the braid as the conductor.
>Powered up the unit with 120VAC, half-rectified into the unit and nothing!
>Gotta tune it. Turned the frequency adjust pot a
>few turns and then the thing came to life. Really loud and nice white arcs
>approximately 15 inches long. Not bad seeing the thing isn't tuned too well
You don't have any idea how LUCKY you are =) I have blown a pair of MOSFETs
on each test for about 10 times.
Sometimes on stupidly low inputs like 50 VAC.
Turns out to be a poor choice of power supply routing, ringing up across
the MOSFET bridges. I killed 450 V MOSFETs from 30 V once!!
Anyway, just wanted to let you know how lucky you are to have 15 inch arcs
on first go - I've had maximum 10 inch sparks before BANG!
BTW, you start to get twitchy after having MOSFETs explode like
firecrackers 100% of the time - you never know how far up the variac to go =)
I think its fixed now tho, gotta replace 4 MOSFETs and give it another whirl =)
>and haven't really played with the primary coupling or # turns etc... Ran
>for 15 minutes (man lots of ozone!!!), and the FETs are actually COOL to the
Yeah that's another tricky thing to achieve when using homemade pulse
transformers to drive the gates... On high supply currents anyway..
>Now, put up my 120-240VAC transformer in the circuit. Now i'm running
>240VAC, half-rectified into the full bridge circuit.
>WOW!!!!! The thing comes up and is super loud for a solid state coil. Fat,
>white arcs with a low frequency cackling hum almost 30 INCHES LONG!!!!!!
Once again, lucky so-and-so =)
>Look out conventional coils. Ran again for 15 minutes (boy its getting hard
>to breath down here!) and the heatsinks are only slightly warm. Well,
>tomorrow, we'll put the variac in the circuit and work up to 480 volts
>input, half-rectified. Wish me luck.
I think you don't need it =) But good luck =)
>The most recent pictures and specifications of this new coil are at the
I must congratulate you on the board - it's very pretty =) Lots of chips, I
suppose you put a lot of thought into it, so no wonder it worked =)
I have decided that breadboarding the logic of a coil driver is OK for 24V
tests but not a good idea when running mains input =) The coil couples very
well to the breadboard, inducing faults that shouldn't be there... But that
was expected anyway...
Well.. I'm impressed and curious. If you want to talk more off list I'd be
BTW if anybody replies then please CC to my address as otherwise I probably
won't notice it.