Re: MMC

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

Original poster: "Terry Fritz" <twftesla-at-uswest-dot-net>

Hi Samuel,

I didn't have the inductor in the model and I also did it at 60Hz AC
instead of 50Hz.

I updated the model.  the *.sch file is the MicroSim model file.

http://hot-streamer-dot-com/temp/samuel2.gif
http://hot-streamer-dot-com/temp/samuel.sch
http://hot-streamer-dot-com/TeslaCoils/Programs/Programs.htm

So for 50Hz with a 47.75mH inductor in the input I get the following.
Cap size: 50nF
BPS:  100
Peak firing voltage: 21.7kV
220 line current: 9.8 amps
Power to primary cap: 813 watts
Arc length:  ~50 inches
RMS Primary Cap Current:  12.7 amps

So your MMC should be 50nF, 24kV, at 13 amps RMS.  

Usually just a 10Meg ohm 1/2 watt carbon resistor across each individual
capacitor will work fine.

I should point out that I don't know everything about your system so this
is my best guess.  Take it with a grain of salt...

Cheers,

	Terry


At 03:01 PM 1/14/2001 +0100, you wrote:
>Hello Terry, all,
>
>> Original poster: "Terry Fritz" <twftesla-at-uswest-dot-net>
>
>> For a 60Hz line at 120 BPS I get 72nF.  I modeled the system and found
>that
>> 72nF would charge at 120BPS for a firing voltage of 22.6kV which is 16kV x
>> SQRT(2).  This incudes your 5 ohm ballast.
>>
>> http://hot-streamer-dot-com/temp/samuel.gif
>>
>> 1/2 x C x V^2 x BPS = 2200 watts throughput.
>>
>> You used 16000 volts but that is an RMS value and you want to fire the gap
>near
>> the peak at 16000 x SRT(2).
>
>Thanks for the info! I didn't give you all the information, because in fact
>my ballast consist of a 5 ohm resistor in serie with a 15 ohm inductive load
>(-at- 50Hz) But if I understood what you wrote, I must model my system with
>PSPICE, and find what is the biggest cap value it can charge. If the cap is
>too low, I will see a high BPS, and if it is too big and the theoretical BPS
>falls below 100and I will see no brakings at all, for the SG braking voltage
>will never be reached. The biggest cap value for my system is the one that
>will fire at 100BPS Is it right?
>
>I also have another question concerning bleeding resistors across each cap.
>How do I choose the value? If it is too low, it will ruin the cap
>proprieties, and if it is too high, it will be useless, so what is the
>typical value I should use?
>
>regards
>
>Samuel
>
>