RE: [TCML] Re: IGBT CM600 max current ?

["Gary Peterson" <g.peterson@xxxxxxxxxxxx>]

Greg wrote:
> . . . In my opinion, it does not make sence to speak about BPS with a [CW
oscillator type] coil like this, unless you pulse it.

Yes, it is a CW (continuous wave) oscillator.  I am pulsing the 137 kHz
transformer at a rate equivalent its resonant frequency and with a 49% duty
cycle.  Rapid rise time and cut off by the circuit controller or break, that
is to say, the solid-state switch, is critical to achieving proper
performance.  I call this switching rate the "break rate" with the unit
being "breaks per second" or "BPS."

I have been planning a 75 kHz Tesla coil with an improved power amplifier,
incorporating a single CM600, for my next project.  It occurs to me now that
the CM600 would not be able to keep up at that frequency, allowing fully
'undamped' CW operation.  

> . . . you could only achieve up to 2500 BPS, because the [50kHz] coil
rings around 5-10 cycles at Fres . . . so all in all, there is not time
available to get any higher.

In other words, the fastest rate at which I will be able to get the CM600 to
switch on and then off is 2,500 times per second with an 'on-and-then-off'
interval of 10 microseconds (.00001 sec.), do I have that sort of right?
I'm a little confused by your explanation.

> Unfortunately, the broken links are so forever.

Do you still have the original images?

G.P.


-----Original Message-----
From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On Behalf
Of Finn Hammer
Sent: Friday, December 12, 2008 9:05 AM
To: Tesla Coil Mailing List
Subject: Re: [TCML] Re: IGBT CM600 max current ?

Gary,

In another post I see that your Tesla Coil is a quite different animal 
than the one I use.  Yours is a CW oscillator type.  In my opinion, it 
does not make sence to speak about BPS with a coil like this, unless you 
pulse it.

Mine is of the disruptive type, I`d say it is an ordinary tesla coil, 
only, the spark gap has been replaced with a CM600 brick.
Since the brick only holds off 1200V max., the capacitor has to be as 
big as possible, to get a decent bang, and this has been made so, by 
using a 2 turn primary, wound inside the secondary.
The resonant frequency is around 50kHz.

In my first post to you, I suggested that you could only acheive up to 
2500 BPS, because the coil rings around 5-10 cycles at Fres, and after 
the cap has to be recharged also,  so all in all, there is not time 
available to get any higher.

Unfortunately, the broken links are so forever.

Cheers, Finn Hammer



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