So, to recap: I've got some Very Important Stuff presently operating under conditions that it should never, ever be subjected to. There's not a darned thing I can do about it, either, other than make adjustments to the thing that powers said Very Important Stuff, and which will have a negative effect on my employer's product. They will, however, not have as much effect as what will happen if the Very Important Stuff breaks.
To add to the fun, the stuff that's not working is powered by transformers that run on three-phase electricity. The markings on the old ones may not be especially readable. The new ones must be connected exactly the same as the old ones. The new and old ones are not physically identical.
So what am I doing about it right now? What I can: nothing. I'm going to go take a writing class. Perhaps I should think of the class as Plan B.
BUILDING A 1:1 BALUN
4 years ago
11 comments:
Sometimes (as in a situation like this) is the best thing to do.
As Heinlein said, 'when in doubt, do nothing'.
Raz
My usual experience with 3 phase equipment was to wait for the riggers to land it.
Then drill the foundation holes and align the equipment.
Then after the pipefitters built and connected all the piping the electricians would arrive, hook up the power and then bump the controller to check the direction of rotation.
In an eerie foreshadowing of the USB connector thing, and even though the chances of a correct rotation were 50/50, I don't think the equipment ever rotated in the correct direction when we tried it for the first time.
And no matter how carefully the systems were checked, the first time you pressurized the system with the pump, you usually heard someone screaming from somewhere in the machinery space, "Turn it off, turn it off!"
Raz, that's a great one. Need to re-read some Heinlein future history.
Ms. Bobbi, good luck. Reminds me of the bad old days of the dot-com boom, where we had a huge op-ex account, but no cap-ex. I can't tell you how many crummy old cisco 2501s I had to babysit. And before that, trying to replace the very poorly marked power supplies on PCs with AT style power, where the first sign of having wired it wrong was the switch assembly slagging itself in a glorious blue glow. Good times, laughing at your coworkers when they'd smack their heads on the underside of the desk, and then cursing like a sailor when it was your turn in the barrel.
Meh... Piece of cake. Been dealing with three-phase power 120 to 500,000 volts for forty years. I'd show up and help you for a nominal fee and expenses.
Or, more seriously, send me pictures of the problem equipment. We can talk.
Mostly Cajun
Electrical guru for five states worth of interstate pipeline
The equipment in question consists of three single-phase transformers in separate enclosures, 800-some feet in the air, primaries of the three connected delta, secondaries wye and a very high penalty for incorrect connection. This thing runs heating current directly though a transmitting antenna to de-ice it, several hundred Amperes.
When you say "directly" you mean like using a welder to thaw out a frozen pipe?
??? And it does this with AC? Or does it rectify three-phase to DC?
MC
The radiating element of the antenna consists of a large, open spiral of large-diameter stainless-steel wire, supported by longish insulators around a central hollow steel pillar. Through some clever electronic thinking, the system is able to run a high current through the steel wire without affecting the transmitted signal. There are three sections of this, with RF power divided to feed them, and each one is getting AC current from one phase of the three-phase, stepped down from 480 V to 24 V.
Thanks! Never knew how they did that, well, actually I never knew they did that! Ah, one more bit of knowledge to tuck away to impress the grandkids....
Yes. Thanks for the illumination. I never worked with any antennae that required deicing. All mine were attached to airplanes.
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