Re: MOT Coil operational notes

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Nicholas Field by way of Terry Fritz <twftesla-at-qwest-dot-net>" <nick.field-at-hvfx.co.uk>

Steve,

I would suggest that, even in a DC supply, shunted power transformers are a
good thing.  Simply from the safety point of view the shunts make the
results of any fault on the HVDC rail far less catastrophic, by leaving them
in you could well save yourself a set of toasted rectifiers in the event of
a short.  They also reduce the danger to life and limb if one were to come
into contact with the output.  Yes, 14mA can kill, but you're a lot deader
at 10A than at 500mA.  People have survived shocks from pigs, so limiting
the output current to the lowest value needed for satisfactory coil
operation seems sensible.

The shunts also serve to limit the inrush, which saves messing around with
thermistors or variacs, and reduce the potential for any large current
spikes on the low voltage wiring.  Additionally, although this may not
matter to you, they will reduce the 3rd harmonic feedback into the mains.

Safe (DC) Coiling,
Nick
_______________
Nick Field, HVFX
www.hvfx.co.uk



----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Tuesday, December 03, 2002 3:18 PM
Subject: Re: MOT Coil operational notes


 > Original poster: "S & J Young by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<youngs-at-konnections-dot-net>
 >
 >
 > To all MOT users,
 >
 > It's time to reach a consensus regarding whether to leave in or remove the
 > shunts.  From the below, it seems Tim J would vote to remove them.
Assuming
 > one controls the primary current by some means other than the MOT magnetic
 > shunts (e.g. ballast, DC resonant chargers or H-bridges, etc.), then what
 > are the performance pros & cons of shunt removal?
 >
 > Thanks,
 > --Steve Young
 >
 > ----- Original Message -----
 > From: "Tesla list" <tesla-at-pupman-dot-com>
 > To: <tesla-at-pupman-dot-com>
 > Sent: Saturday, November 30, 2002 4:08 PM
 > Subject: Re: MOT Coil operational notes
 >
 >
 >  >
 >  > Original poster: "Tim J by way of Terry Fritz <twftesla-at-qwest-dot-net>"
 > <digital_raven45-at-hotmail-dot-com>
 >  >
 >  > sounds great Ted.
 >  >
 >  > I've recorded some info on my improved 6 pack coil too:
 >  >
 >  > 150 nF surplus capacitor/92.7 kHZ/newer 4" 27AWG (teflon treated) wound
 >  > secondary/
 >  > the 6 pack safety gaps are at optimal spacing w/ exactly 7.5mm a side.
 >  > the ARSG, usually spins at 10,000 RPM...for BPS rate...not really sure.
 >  > *the MOTs have been de-shunted and an arc welder ballasting is used to
 >  > control current input. Usually I set the unit at 80% power. MOTs are
are
 >  > experiencing low amount of heating, compaired to when they had shunts
in**
 >  > power draw in total is 9-11 kW, depending on setting.
 >  >
 >  > streamer length from Tesla Coil: ~5.2m ...my MOTs are holdin' up fine.
No
 >  > need for chokes, or big safety curcuits as these are low impedence
 > trannies.
 >  >
 >  >
 >  >
 >  >
 >