WEBVTT

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Why is a transformer
core normally

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earthed at one
intended point?

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The connection
controls the core's

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electrical potential.

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An unintended second
contact can close

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a loop through the core,

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frame and tank.

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When changing magnetic
flux links that

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loop, circulating
current can produce local

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heating.

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A metal chip,

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displaced sheet or
damaged insulation can

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create that extra contact.

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Keep the build
clean and protect

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core-to-frame insulation.

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Before energization,
use the approved

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inspection and
test procedure,

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with the results recorded.

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Compare the condition
after transport with

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the factory baseline.

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One intended connection,

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protected insulation,
and verified

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assembly:

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that is the control.