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Author Topic: Recording/monitoring power surges?  (Read 9070 times)

Mike Sokol

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Re: Recording/monitoring power surges?
« Reply #10 on: June 05, 2014, 07:46:59 am »

Most was on my distro which is tied into a dedicated 100amp disconnect, attached to the building switchgear... if neutral/ground were reversed I almost think it would be irrelevant. (Not "correct" by any definition, but they're effectively bonded at the other end... Still, I feel like this comment might start a flame war.)

You're correct that is EVERYTHING is powered from a reversed G-N connection that there should be no damage. But the point that was made that if you cross connect gear with XLR cables that have been plugged into correct and incorrectly wired G-N, then large currents can flow into circuit boards during peak loads. Been there, seen that, smoked the gear. Don't worry about flame wars here. I'm not going to allow it. We're all learning and you would not believe the things I've seen built by electricians and engineers who should know better.

I'm not aware of issues elsewhere in the building but all network components are on surge/UPS... most devices including phones are POE, and the POS terminals are probably pretty rugged. We've had a LOT of trouble with light bulbs burning out in the event hall but they're fancy halogens and the prevailing theory is loud music vibration is killing them. I'm not sold.

Surge protectors are overrated solutions since they really only clamp voltage spikes and rely on a solid ground to work at all. So a high impedance ground can actually channel a spike from nearby lightning or collapsing magnetic field opening up right into the ground of your gear. And I don't buy into the loud music killing halogens either. That could be the smoking gun.

The Ashly amp going out is the most troubling. It's one of a pair that share a standard dedicated outlet. One is fine and the other goes into over-current protection on all 8 channels even if nothing's connected; even channels that have NEVER had a load attached. Could just be a bad egg. The amp brags about multiple levels of protection, but specs say 120VAC +/- 10%, which isn't a ton of wiggle room. (Also troubling is I've left voice mails for Ashly on Saturday and Wednesday and haven't heard back... must be vacation week?)

Sadly, most service centers are swap shops, so even if they do the repair they probably won't do a component level diagnostics. They'll just swap out the entire circuit board which won't give you any solid info on what the failure mechanism might be.

I do suggest you borrow or purchase some kind of circuit analyzer such as a Amprobe INSP-3 or SureTest Analyzer. They can provide a lot of information about ground impedance, voltage droop under loads, etc... I find myself doing this more and more for troubleshooting.
Mike Sokol

Adam Ellsworth

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Re: Recording/monitoring power surges?
« Reply #11 on: October 06, 2014, 04:00:42 pm »

I know this is an old thread but I thought I'd post a follow-up for the Google archives...

The building owner contacted the power company and they (unknown to me) attached a monitor for 18 days (!) and then sent us a dozen graphs that their engineer had reviewed. (Peak/Min/Avg for Voltage, frequency, and current for all three phases plus neutral.... I was glad to see detail.) There were a couple minor events, all brief sags, and the engineer had noted causes for each (one was severe storms, another was a phase outage "elsewhere on feeder") Ultimately they determined everything was within normal but I did feel like they took it seriously at least. It was actually interesting to look at a couple weeks of activity.... there are predictable voltage curves at various times every day and week to week. Phase 1 and 3 stayed between 119 and 125 for the entire period; On day 6, Phase 2 became much more exaggerated (between daytime/nighttime) and barely squeaked in between 115 and 126 for exactly 7 days - and then was perfectly normal again. Maybe it was just a hot week.

BTW since then I programmed my computer's UPS Battery to write voltage to a spreadsheet - all I have is voltage but my residential power is FAR more stable, usually varying only a couple degrees in a 24-hour period.

We've had no other equipment failures but a number of light bulbs burned out one night in the restaurant just a couple weeks ago. I'm surprised there's not a whole-building surge unit like I've seen other places, and they don't seem extremely expensive, so I might recommend they pursue that.

.... so there you go.

Scott Holtzman

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Re: Recording/monitoring power surges?
« Reply #12 on: October 06, 2014, 04:26:45 pm »

Adam, Something still smells wrong.  That testing was done on the building entrance.

The gear that was damaged, especially the laptop charger.  Two questions

1 - Was it a two prong or a three prong plug?
2 - Was the charger wide range (like 90-250V) or just 110Vac?

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