Buck Boost

To: "'Tesla List'" <tesla-at-pupman-dot-com>
Subject: Buck Boost
From: Tesla List <tesla-at-stic-dot-net>
Date: Mon, 2 Feb 1998 23:29:21 -0600
Approved: tesla-at-stic-dot-net

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From:  Thomas McGahee [SMTP:tom_mcgahee-at-sigmais-dot-com]
Sent:  Monday, February 02, 1998 9:59 AM
To:  Tesla List
Cc:  ghunter-at-mail.enterprise-dot-net
Subject:  Re: Buck Boost


> From:  Gregory R. Hunter [SMTP:ghunter-at-mail.enterprise-dot-net]
> Sent:  Sunday, February 01, 1998 10:06 AM
> To:  Tesla List
> Subject:  Buck Boost
> 
> Coiler Types,
> 
> I've been reading the mail about current limiting strategies for
> pole pigs, and I think I'm finally seeing the light.  
> 
> (1) A really big series choke or variable reactor (arc welder, etc.)
> is required to limit current when the spark gap is firing.  
> 
> (2) Series resistors are required to prevent excessive current at the
> beginning of each charging cycle (when the empty cap feels like a
> short) when the spark gap is not firing.  
> 
> (3) The proper combo of choke and resistors yeilds a smooth
> charge/discharge cycle without excessive current draw.  
> 
> Does all that sound reasonable?
> 
> One writer explained that the 230VAC line voltage will divide across
> the choke impedance and pole pig primary impedance, preventing the
> pole pig secondary from developing full potential.  I'm thinking the
> choke/reactor will only drop a modest fraction of the line voltage
> during the charge cycle.  Could this be corrected using the buck
> boost trick with a hefty low-voltage power transformer?  Is the 
> voltage drop worth worrying about?  Just wondering.
> 
> Greg
> 
> Infatuated With My New Pig in East Anglia, UK
> 

Greg,
Congratulations on obtaining a genuine pole pig!

Looks like you have a good grasp on the fundamentals here. Yes, the amount
'dropped' (not exactly the correct word here, but you know what I mean)
depends on the relative inductances of the pole pig primary and the
series connected inductance. You also have to factor in the effect of
any external resistance employed, and whether it is in series or in
parallel. But yes, the idea is to limit the current just enough so that you
are not popping circuit breakers and dimming the lights throughout
the entire neighborhood.

Forget buck/boost. Instead we use the old variac to do that trick. By
wiring it up for an output greater than the input, you obtain the
desired result very simply. Of course, if you don't HAVE a variac
then you might want to try buck/boost, but be forewarned that you will
need a transformer that is capable of handling a LOT of amps!!!

Hope this helps.
Fr. Tom McGahee