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How I calculate the fuse value??

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#1 albaeed


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Posted 04 January 2005 - 03:58 PM

My dears,

How I calculate the fuse value of the output voltage?

for the transformer of ( 1KVA , 380V ) Supplied to transfer to 220v to protect the scheme.

Best wishes,,

#2 marke


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Posted 06 January 2005 - 04:50 AM

Hello albaeed

Fuses are usually sized to protect the cable down stream from them, however if you have a transformer rated at 1KVA 380 volt, then I would assume that this is a three phase transformer, and I also assume that the 220 volt is the phase to phase output voltage.
The input VA and the output NA will be equal (assuming no losses) so the output VA = output voltage (p-p) times root three times output current.
You can calculate the maximum output current from this and determine the minimum cable size to use. You can then select the secondary side fusing.

Best regards

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