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Capacitor 30kVAR 100Arms ?

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carpenter

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I read the text, "Four of 30 kVAR 100Arms 0.47uF capacitor with the total capacitance of 1.88uF."
I do not know what kind of capacitor can you imagine 30 kVAR 100Arms?
30 kilo volt-ampere reactive
100 Amper Root Mean Square

but i do not know what kind of capacitor to look for :grin:
 
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Google power factor correction capacitors.

These are high voltage oil-filled capacitors. They are used to correct power factor in industrial and large commercial applications.
 

The specification looks inconsistent. 30 kVAr and 0.47 µF means either high voltage of about 15 kV for 50 Hz operation, then the current is wrong. Or very high frequency.

Most likely it's a typo, please check.

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Could it be mF instead of µF?
 

Well, all this is about a device on the table and with performance up to 1kW. Working frekvenci is 110kHz, capacitors serves as parale resonant in RLC
 

110 kHz, I see. It's unusual to specify high frequency capacitors by kVAr value, saying 110 kHz 300 Vrms respectively 100 Arms would be clearer.

The capacitor block can be possibly made by paralleling many PP foil capacitors, passing more than 10 Arms through a single capacitor is unrealistic. Or look out for special designed high frequency power capacitors, but you hardly get it off the shelf.
 

There are in fact loads of very high power (VAr) capable capacitors for power electronics out there - up to 5kV, at 100's of amps, for even the best dielectrics there is a V vs F curve such that as you raise the freq the applied volts must fall ( and not just due to the increase in current thru the cap ) but for the heating effects in the dielectric as the freq goes up ....
 

There are in fact loads of very high power (VAr) capable capacitors for power electronics out there - up to 5kV, at 100's of amps
Do you remember a capacitor series with roughly the said specification (300 Vrms, 100 Arms, 110 kHz, 0.47 µF)? I know that I can get it custom made, but any off-the-shelf product?
 

Hi FVM - would you really like me to find you a manufacturer? of that exact part? will be a US maker.
 

One constraint is that ESL must be as low as a few nH, thus paralleling many boxed capacitors may be preferable anyway.

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would you really like me to find you a manufacturer
No, excuse me. I don't want to build the circuit and presume the OP can do the search on his own, just want to ask if you you know a capacitor series that covers the range.
 

given than there is approx 15 nH per inch of connection you are never going to get that low in a single cap rated at 100Arms 100kHz.
 
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    FvM

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It's so familiar to me, so I was interested in the use of 30 kVAR, 400V, 100Arms, 0.47 μF capacitors.
Paper is supposed to bear it all, but this is dissertation work for Doctoc philosophy of engeneerinh , with many citation on ieeexplore.ieee.org.

Let's look at it differently
I need resonant capacitor 1 to 2.2uF (3uF) 200A

1. 1pcs DCC 500A resonant capacitor price 94$ , **broken link removed**

2. 4pcs DTR high frequency 0.44UF 3000VDC 60A price 64$

3. many capacitor as it's inexpensive, but I can not guess what current can bear 1pcs of such a capacitor. I do not know what the parasitic properties will be the resultant battery (parasitic induktance etc)
 

I believe the thread is moving towards "useless" if you don't manage to get actual datasheets for the mentioned capacitors. Agree with Easy peasy's comments in post #6 and #10.
 

you might be able to parallel 10 of these for 100A

**broken link removed**
 

Also need to consider the overall circuit layout. A "brick" or axial capacitor can be possibly wired with low inductance - if the current loopback is designed suitable.

you might be able to parallel 10 of these for 100A
Yes, did similar in the past (at slightly lower current level).
 
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