Re[2]: cap/mmc inquirery

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Illicium Verum <sebas@xxxxxxxxxxxxxxxx>


Hello Daniel,

I recommend building 3 strings, this because of 
your budget. Keep in mind that this number might 
be to low if the pulse rate of your capacitors is 
low. You want the best MMC for little money? If 
it is your intention to make a rotary gap instead 
of a static gap, you will end up spending more 
money on capacitors and motor while a static gap 
can save you money on capacitance and can be 
constructed with copper pipes obtained for free 
at a "järnskrot" (I don't know the English word 
for this, but it is the place where they recycle metal)


Than, you have to ask yourself the question if 
you're planning to build a nice one time coil for 
which I recommend you to use the AC voltage 
rating of the capacitor. Or if it's just an 
experiment that should not cost to much? In that 
case you can use the DC rating.


For a static spark gap the RTL capacitance on a 
60Hz system is 9.15nF If you use 18 capacitors 
you won't have to worry about the peak voltage. I 
assume your 1000V rating was the DC voltage of 
your capacitor, and I think I have heard Terry 
once saying that working with DC rating gives an 
average MMC lifetime of 10 hours, keep that in mind.


By using 56nF capacitors instead of 47nF you will 
get a higher capacitance per string.

47nF divided by 18 is 2.61nF where 56nF divided by 18 equals 3.11nF


Now if you build 3 strings of 18 capacitors, each 
rated at 56nF and place those 3 strings in 
parallel with each other you will have a nice 
9.33nF MMC rated at 18000VDC this does cost you 
64.26$ tough (assuming that the price of the 56nF is the same as your 47nF).


I hope this helped you a little?

Kind regards,

Sebastiaan


Thursday, November 3, 2005, 3:49:01 AM, you wrote:


> Original poster: "Langer Giv'r"

> 
<<mailto:transworldsnowboarding19@xxxxxxxxxxx>transworldsnowboarding19@xxxxxxxxxxx>


> no i have a wider range of capacitance options but what would be the

> best MMC for the cheapest price for a xfrm of about 15000 peak voltage?



>>From: "Tesla list" <<mailto:tesla@xxxxxxxxxx>tesla@xxxxxxxxxx>

>>To: <mailto:tesla@xxxxxxxxxx>tesla@xxxxxxxxxx

>>Subject: Re: cap/mmc inquirery

>>Date: Wed, 02 Nov 2005 08:41:07 -0700


>>Original poster: Illicium Verum 
<<mailto:sebas@xxxxxxxxxxxxxxxx>sebas@xxxxxxxxxxxxxxxx>



>>Dear Daniel


>>For that money you will get a 2.61nF MMC.


>>Why?


>>Your peak voltage is 14142V


>>Your MMC should be rated at a littlebit higher, lets say Peak

>>voltage + 10% = 17677V


>>Your capacitor is rated at 1000V, this means 18 capacitors in series

>>will give you a 18000V MMC


>>18 x 1.19$ = 21.42$


>>18 x 47nF in series is a capacitance of 2.61nF



>>What you need is:



>>LTR value based on 110V/60Hz


>>9.15nF for a ssg


>>17.08nF for a rsg



>>This means:


>>If your only option 47nF is you can make 3 of those strings to get

>>7.83nF, this for a price of 64.26$


>>Or you make 4 strings to get a capacitance of 10.44nF for a price of 85.68$



>>Im afraid you won't get there with 30$



>>Kind regards,


>>Sebastiaan





>>Wednesday, November 2, 2005, 2:54:46 AM, you wrote:



>> > Original poster: "Langer Giv'r"


>> >

>> 
<<<mailto:transworldsnowboarding19@xxxxxxxxxxx>mailto:transworldsnowboarding19@xxxxxxxxxxx><mailto:transworldsnowboarding19@xxxxxxxxxxx>transworldsnowboarding19@xxxxxxxxxxx>



>> > hellow everyone, i am oredering some 0.047 1000V polypropelyne film


>> > caps for my MMC.  i dont know how many i should buy tho... i have


>> > about 30$ and the caps cost $1.19 each.  I am most likely using a


>> > 10KV OBIT as power source running at 
23mA.  Help would be very good, thanks



>> > Daniel from Canada




>> > _





>>--


>>Best regards,


>>Sebastiaan






--

Best regards,

Sebastiaan