# Capacitor



## iamatt (Aug 21, 2009)

Anyone know where I could buy a 600v with high amperage? 200 amp?
Thank you for your time.


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## drsparky (Nov 13, 2008)

Maybe on another planet.


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## McClary’s Electrical (Feb 21, 2009)

Capicators aren't rated in amps


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## iamatt (Aug 21, 2009)

mcclary's electrical said:


> Capicators aren't rated in amps


Understood.
Do you know of a supplier that would have something like a 600v cap?
I may need something bigger.

Thank you for your time.


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## drsparky (Nov 13, 2008)

The voltage rating of a capacitor is it limit before physical breakdown. Similar to wire insulation ratings. The ratio of the electrical charge stored between the plates is measured in farads, more commonly microfarads.


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## Toronto Sparky (Apr 12, 2009)

Yuppers.. They blow up real good on over voltage and tend to shower you in paper (well the one I blew up did)


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## John Valdes (May 17, 2007)

What MFD is it you require? 600 volt caps are available and common.


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## drsparky (Nov 13, 2008)

Basic questions: what is the cap used for, AC or DC, voltage and rating in mili or micro farad, is the capacitor electrolytic?


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## mpoulton (Jul 17, 2009)

mcclary's electrical said:


> Capicators aren't rated in amps


Well, actually many are. KVAR or current ratings (which are functionally the same rating) are typical on any capacitor intended for use in high current AC applications - whether for power factor correction, DC blocking, or resonance. I don't think this guy is really asking about that though...


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## McClary’s Electrical (Feb 21, 2009)

mpoulton said:


> Well, actually many are. KVAR or current ratings (which are functionally the same rating) are typical on any capacitor intended for use in high current AC applications - whether for power factor correction, DC blocking, or resonance. I don't think this guy is really asking about that though...


 
I stand by my statement,,,,,,,,just because it's "on" the cap,,,,,,doesn't mean that's what it's rated by. Caps are rated by capacitance


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## mpoulton (Jul 17, 2009)

mcclary's electrical said:


> I stand by my statement,,,,,,,,just because it's "on" the cap,,,,,,doesn't mean that's what it's rated by. Caps are rated by capacitance


http://www.highenergycorp.com/oil/arpage.html

For certain applications, the current handling of the capacitor may be at least as important, if not more important, than the capacitance. For induction heating, for example, capacitor current is a more critical parameter than capacitance - other parts can be designed to accommodate the available capacitance values, but the current rating is non-negotiable and is usually the biggest challenge in selecting a capacitor.

Other example: electrolytic filter caps for power supply input. The usable capacitance may vary by an order of magnitude - 500uF or 5000uF may work just fine. The ripple current rating, however, determines whether that cap's going to overheat or not.

Fairly complete discussion of the current handling of capacitors for such applications: http://www.newark.com/pdfs/techarticles/kemet/Ripple-Current-Capabilities-Technical-Update.pdf

While capacitor current is not a key parameter in every application, it is certainly an important aspect of a capacitor's specifications in AC applications. No capacitor data sheet is complete without current, VAR, dissipation factor, or ESR values - all of which measure effectively the same thing. Without that information, the capacitor cannot be engineered into an AC application without guessing.


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## McClary’s Electrical (Feb 21, 2009)

ok I retract my statement,,,,and to the op........you need to hire an engineer


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