Damage to input side of power supply

[ACCCAM]

We had 10 power supplies go bad on one of our products for a subsea application.The FA report on the power supplies said a high voltage on the input side.The input rating for the power supply is 80-270 V AC .It is being fed from a step up transformer 110-230 V.The power upplies sit inside a stainless stell chamber and we pull a vacuum on it and then purge it with nitrogen.I don'tnot see any point where we could induce such a high voltage.Any response to this is really appreciated.

Thanks,
ACCCAM

 

[itsmoked]

How about lightning?

Keith Cress
kcress -

http://www.flaminsystems.com

 

[itsmoked]

What's the cable length, approximate distribution, and layout?
How much power per unit?
Is this a single ended cable?

Keith Cress
kcress -

http://www.flaminsystems.com

 

[burnt2x]

itsmoked,
I thought I've read "subsea application", therefore lightning is out of the window!
ACCCAM,
Do you take the report as it is? Try looking at possible "transferred surge" from your feeder trafo!

 

[ScottyUK]

You have grounded one end of the step up transformer HV winding haven't you? Ungrounded sources are more trouble than they are worth in all but a very few cases. A fully floating 230V winding will be prone to picking up impulse voltages and transferring them into the power supply.


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If we learn from our mistakes I'm getting a great education!

 

[itsmoked]

Hi burnt2x;
I'm thinking lightning induced on the mains and transfered to the submarine stuff. Not a direct type problem. Could be anything causing a voltage surge.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[sibeen]

I'd have to ask who wrote the report and conclusion on why the power supplies failed.

If it was the OEM I'd take it with a pinch of salt.