Mains in UK can go up to 292VAC for periods of several minutes

[fourtytwo42]

Speechless treez I thought that dead horse was well and truly flogged!! 

[ocset]

Thanks,
The statement that mains can go up to 287VAC was by a very reputable mov (etc) company apps guy.
Im not getting angry about it, if i was angry i would be said to have a short fuse, and i wouldnt be giving you cryptic clues or anything, but it was a very reputable company's apps guy that told us this.

[Monkeh]

Yes, extremely infrequent excursions occur. Note he did not say 'yes, the mains regularly hits 400Vpk-pk and sits there for an hour'.

Your devices are failing. Your theories so far include 'UK mains voltages are hugely unregulated', which is plainly bullshit, and 'our competitors are using microwave guns to kill our products', which is tinfoil hat worthy. Do some actual investigation, invest in data loggers, and hire some engineers with a clue.

[tggzzz]

Yes, extremely infrequent excursions occur. Note he did not say 'yes, the mains regularly hits 400Vpk-pk and sits there for an hour'.

Your devices are failing. Your theories so far include 'UK mains voltages are hugely unregulated', which is plainly bullshit, and 'our competitors are using microwave guns to kill our products', which is tinfoil hat worthy. Do some actual investigation, invest in data loggers, and hire some engineers with a clue.

Indeed.

It appears I was being too subtle for the OP when I wrote "BTW, your statement of probability is woefully inadequate, to the point of being meaningless"! Memo to self: sometimes politeness isn't effective.

[jc101]

Just found some of my old UPS logging data that I must have copied off before the drive failed, not much just 21 April 2016 to 2 July 2016, but a reasonable summary of a couple of months.  The records are minute intervals, with min, max, and average over the minute.  We also have Solar PV fitted not that you can see it in the data.

I've not looked through them but I suspect it is all horribly normal.

Note the .zip will expand into a directory, each 24 hours worth is in a separate file.

[iwtommo]

I quite enjoyed reading this thread - any updates op?

[Gyro]

There's nothing to see here, there are many other threads by the OP with unsubstantiated assumptions. No point in dragging this one up again for enjoyment purposes.

[iwtommo]

Dangit. Ill keep my eye out!

[chris_leyson]

I was testing a linkswitch flyback design last week and wondered why it had shut down at 240VAC, is it getting power ? Checked the primary side, 240VAC going in but when I measured 540V DC across the primary smoothing cap, oops turn it off quick. Seems the inverter I was driving it with was putting out 240VAC PLUS 220VDC, oops finger trouble, no wonder the inverter alarmed. But hey everything survived and it's still working, quite impressive, at least the overvolts protect works.

[ocset]

Thanks, it would be even more impressive if you had a 450V el cap there which survived that(?)
And i know your  x2 caps would likely have been rated to withstand 1700V for a second or two, but for longer, ....and i reckon they would have gone(?)
Your MOV survivied it too(?)

[chris_leyson]

The primary electrolytic, 450V, and the X caps, 275VAC, survived, I changed the electrolytic however. The MOVs are 510V, clamp at 840V so they might have just started to get warm maybe. Linkswitch max drain voltage is 750V. I'm driving the supply from a 1kW inverter, non isolated, it's more convenient than a variac. The inverter keeps alarming because of the high inrush current into the X caps and my power supply is just a tiny part of a bigger system hence the big X caps.

[Zero999]

The primary electrolytic, 450V, and the X caps, 275VAC, survived, I changed the electrolytic however. The MOVs are 510V, clamp at 840V so they might have just started to get warm maybe. Linkswitch max drain voltage is 750V. I'm driving the supply from a 1kW inverter, non isolated, it's more convenient than a variac. The inverter keeps alarming because of the high inrush current into the X caps and my power supply is just a tiny part of a bigger system hence the big X caps.

Yes, electrolytic capacitors can withstand much higher voltages, for quite liong periods of time, without being damaged. I believe they're often formed at a higher voltage, than the maximum rating anyway.

If was a good idea to replace the capacitor but perhaps you should replaced the MOVs too?