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* Posts by prodromos65

4 publicly visible posts • joined 6 Apr 2018

You would expect a qualified electrician to wire a building to spec, right? Trust... but verify

prodromos65
Black Helicopters

My boss and I were tasked with installing a three phase outlet for a new CNC flatbed laser cutter which was being shipped from the USA to Australia via their subsiduary in New Zealand. Since it was coming from the States which has completely different electrical supplies compared to Australia, we asked them to confirm that the necessary modifications had been made for it to be run on Australian voltage. They assured us that it had indeed been modified so we did as we had been asked. The next day, the Rep from the USA arrived to provide training to the staff in the operation of the machine. The power was switched on and the control computer immediately released blue smoke into the air.

No modifications had been made and we soon discovered that it was expecting a 120V-0-120V supply instead of the 415V it was given. Apparently the Rep had no idea about the different supplies outside of the USA. Thankfully all that needed replacing was the computer as the other components only received power after the computer finished starting up. In the meantime we had to source an isolating transformer with a centre tap on the secondary

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Heatwave shmeatwave: Brit IT departments cool their racks – explicit pics

prodromos65
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Re: I've done this too

Got a late night call out on New Years Eve as the Comms room for a Law firm in one of the buildings we looked after had gone down. It turned out that they had scheduled maintenance on the Comms room cooling system that night as network traffic was at a minimum. In order to keep things cool while the crack units got serviced, several portable A/C units had been brought into the Comms room which the A/C contractor had plugged into power outlets on the wall of Comms room, all of which were backed up by the Comms room UPS.

Queue UPS overload alarm followed by immediate power loss to all computer equipment in the room.

It took me a while to get there as the CBD was closed to all traffic on New Years Eve and I had to walk from a couple of kilometers away, so by the time I got there they had already figured out their mistake and had everything running again.

Had another callout to a bank branch that was suffering from heat related issues. The A/C plant on the roof had broken down so an A/C company had brought in portable units to keep things cool, with the hot air being pumped into the false ceiling which acted as the return air of the currently not working A/C plant. Thus, all the hot air came flowing out of the return air vents in the ceiling and the place just got hotter and hotter, since no one had actually thought about how they were actually going to remove the heat from the building. Their computers were already slowing down due to CPU throttling and it would not have been long before their network equipment shutdown.

I explained the basic thermal dynamics to the manager, and the fact that they would soon be unable to trade when their network died. They craned a large temporary unit onto the roof the next day.

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prodromos65
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Re: Pffft Amateurs

A lecturer I had at university commented that the old reel to reel tape drives in use in the computer rooms each had their own cooling system, and there was a space in the back of each which was just big enough to fit a six pack of beer.

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*Thunk* No worries, the UPS should spin up. Oh cool, it's in bypass mode

prodromos65
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Re: My one win over beancounters

Putting it in bypass mode is fine. The only issue is that no where in the manuals does it state how to take it out of bypass mode. Once you've changed your batteries you perform a battery test and if it completes successfully it will put the UPS back into ONLINE mode.

This also follows if you have an external bypass switch. After you've done maintenance on the UPS, switch from BYPASS to TEST, power up your UPS and put it into internal bypass. Switch the external switch to ONLINE and then do the battery test. The SMART UPS's need to monitor the load while in internal bypass to be able to supply the correct load when it goes to online. If you put it online and then switch the external switch back to online the UPS will fill its pants and go into overload alarm.

We once sent back a perfectly good UPS because the person responsible did not know the procedure and assumed we had just installed a faulty unit (replacing the old one which had failed)

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