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Use the chassis as the heatsink - Need safety advise

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pha0001m

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I need your advises in regarding how safe it is to mount a high voltage NMOS STW12NK95 directly the chassis for heat dissipation purposes.

The operating voltage of the power NMOS(M4,M3) is 420VDC. The chassis is obviously earthed. The power supply is designed to float e.g. isolated from earth, (but let assume the worst case scenario that it is not)

I know that an insulating/thermal pad can be insert between the NMOS and the aluminium chassis to achieved electrical isolation. But is this enough? Is this safe? Please do shared any documented works that shows how to do it safely.
 

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KlausST

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Hi,

Many countries have their own regulations on safety with electricity.
You have to look for these documents. Often it's not legal to copy, or give these documents to other persons.
Usually you have to pay a lot...

There is no general rule what distance to use, because it depends on many factors likevoltage, humidity, dust, safety level and so on...

Klaus
 

chuckey

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If you bolt it to the inside of your chassis and use the isolating bush so the bolt head is earthed to the chassis there should be no personnel safety issues. A warning label on the inside to remind maintainance people that it has high voltages on it would be nice.
Frank
 

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