[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: [TCML] DC coils



Hi Steve,
Thanks for that.
What would you estimate the losses to be like by charging the capacitor
through a spark gap?

Thanks.

On Wed, 26 Jan 2011 18:43:28 -0700, "S&JY" <youngs@xxxxxxxxx> wrote:
> Carlos,
> 
>  
> 
> Great choice to go with DC!  
> 
>  
> 
> With the usual DC powered Tesla Coil using a charging reactor and
De-Q-ing
> diode, you have to use a break rate above a certain minimum, or the
rotary
> spark gap will start power arcing.  You are probably familiar with
Richie's
> wonderful website, specifically
> http://www.richieburnett.co.uk/dcreschg.html#resonant which gives a very
> good explanation of DC resonant charging Tesla Coil theory and practice.
A
> good side benefit of this scheme is that you end up charging your
primary
> capacitor to nearly twice your supply voltage.
> 
>  
> 
> I worked out a better way to do DC resonant charging which I use on my
> coils.  With this method, your break rate can be as slow as you want
with
> no
> power arcing or other bad effects.  And your break rate can be as high
as
> you want, subject to the current capability of your DC supply.  A
further
> benefit is that when your primary capacitor discharges into your
primary,
> the power supply is completely disconnected from the primary circuit.
> 
>  
> 
> To do this requires a second gap on your RSG.  The gaps are arranged so
> that
> one gap charges your MMC capacitor through a charging reactor (only
needs
> to
> be a fraction of a Henry) and a De-Q-ing diode.  Then the rotor rotates
so
> that the second gap discharges the MMC into your primary.  Further
rotation
> repeats the cycle - charge the MMC from your power supply then discharge
> the
> MMC into your primary.
> 
>  
> 
> DC coils are fun.  You can vary both the supply voltage and the RSG
break
> rate.  As you can imagine, the higher the break rate, the more "robust"
are
> the streamers.  For my coils, break rates in the 200-250 range seem to
be
> the sweet spot for best streamer length vs power input.
> 
>  
> 
> My HV rectifiers are strings of 1N5408 1000 volt 3 amp diodes with
enough
> diodes in each string to be rated for roughly twice the highest voltage
> they
> must handle.  They can handle charging current pulses of 30 amps at 400
> bps.
> This is the least expensive approach.
> 
>  
> 
> Please let us know how your DC coil works out.
> 
>  
> 
> --Steve Y.
> 
>  
> 
>   _____  
> 
> From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On
Behalf
> Of lightningfor@xxxxxxxxxxxxxxxxxxxxxx
> Sent: Wednesday, January 26, 2011 3:33 PM
> To: Tesla@xxxxxxxxxx
> Subject: [TCML] DC coils
> 
>  
> 
>  
> 
>> I am planning to build a rectified 3phase - DC tesla coil with a
> variable
>> rotary gap to give a variable pulse rate, and I am wondering about the
> use
>> of the inductor (charging reactor)...
>> I can see this is used for several purposes.
>> To limit the charging current to protect the diodes and control the
>> maximum pulse per second rate.
>> Also, to create a high impedance for the HF circuit so it can oscillate
>> with out the power supply being a short accross it...
>> I can also see that there would be an optimum size (inductance) to best
>> match a given pulse per second rate for best performance.
>>
>> What I am wondering is if it is possable to build a dc coil with a
>> variable pulse rate (without changing the inductance).
>> For example, a DC coil with a rotary gap with a variable speed drive.
>> And what effect does varying the speed of the gap have on the output?
> 
>> Has any body had any experience with this?
>>
>> Thanks,
>>
>> Carlos
>>
> 
> 
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxx
> http://www.pupman.com/mailman/listinfo/tesla 
> 
>   _____  
> 
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 10.0.1191 / Virus Database: 1435/3404 - Release Date: 01/26/11
> 
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxx
> http://www.pupman.com/mailman/listinfo/tesla
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla