MMC where to buy

[DerStrom8]

these?

https://www.cde.com/resources/catalogs/941C.pdf

Which ones? That's a datasheet for an entire series

 

[billybob]

Which ones? That's a datasheet for an entire series

oh crap your right XD I think I need to take a break.

 

[billybob]

Also quick question, how big is too big for the toroid? I have two 12 inch diameter steel dog bowls and 6 foot air duct. Resulting in 20 inch diameter / 4 inch height toroid. Is this to big for my 4.5 inch diameter secondary?

 

[DerStrom8]

Also quick question, how big is too big for the toroid? I have two 12 inch diameter steel dog bowls and 6 foot air duct. Resulting in 20 inch diameter / 4 inch height toroid. Is this to big for my 4.5 inch diameter secondary?

Questions like this are best answered by simulations and experimentation. Build your coil in JavaTC and try a number of different values.

 

[billybob]

So I’m working on the strike rail today, and I was going to attach four wooden boards so the strike ring would be about 6 inches above the primary. My question is would the primary cause the zinc plated mending braces to melt or would it effect the emf of the primary? Here is a picture of what I’m trying to do...

 

[billybob]

Or would this be better?
Probably less stable, but I’m not sure if it would help.

 

[DerStrom8]

From personal experience, I'm going to recommend avoiding metal fasteners altogether around the primary coil. It is, in reality, an induction heater as you seem to understand. I would suggest using wooden fasteners (dowels, wood glue) in this application.

 

[billybob]

Are these guys legit? **broken link removed**
Thinking on buying 100

 

[billybob]

Oh never mind. Minimum is $500

 

[billybob]

I am buying the caps today. Should I go with the Cornell Doublers 2000 volt or 3000 volt? Both 150nf

 

[DerStrom8]

I am buying the caps today. Should I go with the Cornell Doublers 2000 volt or 3000 volt? Both 150nf

Presumably you are asking whether to go with the 940C or the 942C series? The 940C series (3kV) have a substantially lower current rating and are most likely not suitable for Tesla coil applications. Use the 942C series.

Also, bear in mind the voltage rating displayed (i.e. 2kV) is DC, not AC. The AC rating of these caps is only 500V, so that is the value you need to use when sizing your capacitor bank.

 

[billybob]

Presumably you are asking whether to go with the 940C or the 942C series? The 940C series (3kV) have a substantially lower current rating and are most likely not suitable for Tesla coil applications. Use the 942C series.

Also, bear in mind the voltage rating displayed (i.e. 2kV) is DC, not AC. The AC rating of these caps is only 500V, so that is the value you need to use when sizing your capacitor bank.

Ok I’ll go with the 942C then. Well it’s a voltage multiplier pulsed DC so it‘s not as detrimental as a pure sine wave right? Everyone else I talked to who has made MOT Tesla coils have gone by the DC rating and double or triple it to the output power. Also that go way over my budget and be a little overkill. I’m getting 50 caps

Thanks you DerStrom.

 

[DerStrom8]

Ok I’ll go with the 942C then. Well it’s a voltage multiplier pulsed DC so it‘s not as detrimental as a pure sine wave right? Everyone else I talked to who has made MOT Tesla coils have gone by the DC rating and double or triple it to the output power. Also that go way over my budget and be a little overkill. I’m getting 50 caps

Thanks you DerStrom.

The purpose of capacitors in a Tesla coil is to create a resonant circuit with the primary coil. The current which they will be seeing during operation is about as pure a sine wave as you'll get

Hopefully they will perform well, just be aware that MMCs often blow a cap here and there. That's one of the main reasons they were invented - to make it easy to change just one or two (relatively) cheap capacitors instead of having to replace a single, giant, expensive capacitor. 942Cs are fairly rugged, but don't be surprised if you lose a few.

P.S. Oh, and please, call me Matt!

 

[billybob]

The purpose of capacitors in a Tesla coil is to create a resonant circuit with the primary coil. The current which they will be seeing during operation is about as pure a sine wave as you'll get

Hopefully they will perform well, just be aware that MMCs often blow a cap here and there. That's one of the main reasons they were invented - to make it easy to change just one or two (relatively) cheap capacitors instead of having to replace a single, giant, expensive capacitor. 942Cs are fairly rugged, but don't be surprised if you lose a few.

P.S. Oh, and please, call me Matt!

I just realized that after I sent it. A giant LC circuit is all it is. I have faith that these will hold up nicely and according to deepfriedneon I will only need 21 caps (I will do more for insurance) 65nf is what I am aiming for.

Thanks Matt. IT’S FINALLY GETTING THERE!

I’m super excited.

 

[billybob]

Um can someone fix the above post please?

 

[DerStrom8]

Um can someone fix the above post please?

Fixed. Looks like you had two quote blocks, and accidentally posted your reply inside the second one

 

[billybob]

Fixed. Looks like you had two quote blocks, and accidentally posted your reply inside the second one

Yup that’s what happened XD

 

[billybob]

Is tti.com a reliable electronic distributor? Or should I pay the extra 40 dollars and go with mouser?

 

[billybob]

Ok I bought 50 caps from tti.com it costed $260

 

[DerStrom8]

TTI is trustworthy.