Question on Capacitors

Thread Starter

Abdel_Rahman

Joined Jul 19, 2016
42
It was a defective capacitor in induction welding machine....

Machine consists of step up transformer, rectifier, and osscillator circuit.
Capacitor located after rectified output of 10000V transformer, Ampere at primary side is in the range of 100A,
oscillator frequency rating is 48MHz
Capacitor rating is 20000V, 0.01uF.

Can I replace that defective capacitor with a series of say 220 "2.2UF 630V Ceramic Capacitor"??

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1- General sketch of the machine parts
output.png.png===============================================================================
2- Capacitor to be replaced
1601303681300.png
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3- Capacitors for replacing
1601303463993.png
 

bertus

Joined Apr 5, 2008
20,762
Hello,

The capacitor to be replaced is an 10 nF 20kV capacitor.
You will need at least 32 of the given capacitors in series.
The resulting capacitance will be lower as the origenal capacitor.
The problem will be balancing the voltage accross the capacitors.
The capacitor you show as replacement will not work and will likely blow almost instantly.

These will be a correct replacements for the capacitor:
http://hvstuff.com/doorknob-capacitor-high-voltage-ceramic-capacitor-20kv-10000pf
http://hvstuff.com/30kv-10000pf-high-voltage-polystyrene-film-capacitor
http://hvstuff.com/0-01uf-20kv-high-voltage-capacitor-hv-tesla-coil-ham

Bertus
 

Thread Starter

Abdel_Rahman

Joined Jul 19, 2016
42

MisterBill2

Joined Jan 23, 2018
7,015
I suggest replacing the failed capacitor with the same kind and the same, or higher, voltage rating. There are additional considerations such as current capability and temperature rating, and since the machine is probably important it is wise to use the correct replacement.
AND, you need to discover the reason that the capacitor failed, so that the replacement does not quickly fail.
 
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