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LD LANGER

Mon May 02 2011, 07:26PM

Registered Member #3824 Joined: Sun Apr 10 2011, 08:29PM
Location: Edmonton, Alberta, Canada
Posts: 54

Hello, so I have a stupid question that I probably could deduce myself but just want reassurance. Actually its two questions.
1. If the primary current can be upwards of ~100A, how can the small leads from individual MMC caps handle this current?
2. How long can I reasonably hold my soldering gun on the leads while soldering before I start to destroy the dielectric?

Thanks,

Daniel

Nah

Mon May 02 2011, 07:38PM

Registered Member #3567 Joined: Mon Jan 03 2011, 10:49PM
Location: USA, 1960s
Posts: 260

1. It is a peak of more than 1000 amps. The current goes up and down, up and down.
2. Untill the plastic starts to melt.

Mads Barnkob

Mon May 02 2011, 08:06PM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

LD LANGER wrote ...

Hello, so I have a stupid question that I probably could deduce myself but just want reassurance. Actually its two questions.
1. If the primary current can be upwards of ~100A, how can the small leads from individual MMC caps handle this current?
2. How long can I reasonably hold my soldering gun on the leads while soldering before I start to destroy the dielectric?

Thanks,

Daniel

1. Its because the pulses only last for micro seconds, at highest mili seconds.
2. Depending on how close to the component you solder on the lead, but a few seconds should be enough with a clean iron, flux and prepared leads.

LD LANGER

Tue May 03 2011, 04:32PM

Registered Member #3824 Joined: Sun Apr 10 2011, 08:29PM
Location: Edmonton, Alberta, Canada
Posts: 54

Mads Barnkob wrote ...

So, even if pulses last only micro seconds, what would be an estimate of the duty cycle? I mean, the primary conductors should be sized according to the RMS current, correct? How would this remotely be calculated? I think I'm failing to understand the fundamental aspect of the tank charge / discharge. The charging circuit will charge the tank cap depending on the resonant frequency of the charging circuit (DC Resonant charging coil) in the order of hundreds of milliamps at twice the resonant frequency. The primary circuit will however transfer its current on the order of ~hundreds of amps at the resonant frequency. So this implies the tank cap does not dump all its energy in one cycle as this would cause the rms current to near the pulse current and everything would melt.

James

Tue May 03 2011, 05:24PM

Registered Member #3610 Joined: Thu Jan 13 2011, 03:29AM
Location: Seattle, WA
Posts: 506

Many types of coils operate in burst mode, where the high frequency resonance occurs in short bursts repeating at a much lower frequency. The peak current can be orders of magnitude greater than the RMS current. Wires are sized for the RMS current, although with high frequency you have the skin effect to complicate things. I don't think most people try to calculate the wire size, but rather pick something practical based on experience of others or experimentation.

Mads Barnkob

Tue May 03 2011, 08:35PM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

LD LANGER wrote ...

Mads Barnkob wrote ...

Richie Burnett wrote some excelent articles on Tesla Coil operation, you should read more on his site:

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