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Registered Member #561
Joined: Sat Mar 03 2007, 02:46AM
Location: Adelaide Australia
Posts: 230
aonomus wrote ...
Depending on the venue you are at, you may be required to hire a professional electrician to do your service wiring due to insurance policy requirements. It could be a barn, shed, or professionally run venue, however insurance policies vary... check with the owner, and your own insurance company.
Also, you should read up and understand star or Y (wye?) 3-phase vs delta 3-phase. Essentially delta is the L1-L2, L2-L3, L3-L1 wiring in your second diagram with no neutral, and iirc is used more for 3-phase motors, whereas the L1-N, L2-N, L3-N configuration is used for separate 1-phase services.
The venue is going to be my new houses 150m2 shed/studio thing so I'm not worrying about the owners complaints
Registered Member #347
Joined: Sat Mar 25 2006, 08:26AM
Location: Vancouver, Canada
Posts: 106
Since you have a non-linear load, PFC caps won't help your power factor, there's really nothing you can do except use power factor corrected power supplies in all the LAN party PCs.
Registered Member #561
Joined: Sat Mar 03 2007, 02:46AM
Location: Adelaide Australia
Posts: 230
tesla500 wrote ...
Since you have a non-linear load, PFC caps won't help your power factor, there's really nothing you can do except use power factor corrected power supplies in all the LAN party PCs.
It's a bring your own computer lan party so I can't do that, I'll just have to do my best evenly distribute the power load
Registered Member #72
Joined: Thu Feb 09 2006, 08:29AM
Location: UK St. Albans
Posts: 1659
An unbalanced load on each phase just means neutral current flows, it doesn't need correcting, that's what the neutral to the house is for. The power supplier, who's hauling tens of thousands of amps around will be worried about balance as his 200kV neutral is going to be thinner, or even absent. However diversity is going to come to his aid, and your tiny bits of unbalance is going to average out with the rest of the district's contribution to an insignificant fraction at the distribution transformer.
You can load each phase to any random fraction (0-100%) of 32A, and your neutral current will never exceed 32A - at least that's true for similar loads, and unless you do anything artificial like put all the big mothers on one phase, all the old PCs on another, they will be similar. And yes, you can trim the balance with PFCs, but it doesn't really matter.
Third harmonic (and 9th etc, the so called triplens) will cause neutral current flow even when otherwise balanced, these would be caused by big rectifier input capacitor banks, such as were used in power supplies in the bad old days. AFAIK, all PSUs above 300 watts built in the last few years must have active input PFC correction, and so have insignificant triplen draw, and most smaller PSUs as well, even though it's not mandatory, as the input control chips are available and low cost. Even so, I think you would be hard pressed with a room full of old computers to overheat a 32A rated neutral. And what sort of LAN partygoer is going to be hefting less than 300 watts?
If you want to say you've done your bit to achieve balance, then count your guests and put roughly a third on each phase, it really doesn't need to be any more accurate than that.
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
I wouldn't worry too much, PC PSU watts are measured the same way as car audio amp watts. (Take the real continuous power it can supply without catching fire, and multiply by the marketing guy's shoe size, or his IQ, whichever is less.)
As others have said, PFC caps won't help, as they mostly correct displacement power factor, and don't much help harmonic power factor. Third harmonic is the usual culprit, as the fundamental currents from the three phases cancel in the neutral wire, but the third harmonic currents add. The other triplen harmonics do too, but the third is usually strongest. All you need to do is use a neutral conductor the same gauge as the phase conductors, and it will handle it safely. It's only undersized neutral wires that cause trouble.
And it's between phase and neutral for 240V! Phase to phase is 415V. If you get this wrong, your next LAN party could be your last.
Registered Member #561
Joined: Sat Mar 03 2007, 02:46AM
Location: Adelaide Australia
Posts: 230
Steve McConner wrote ...
I wouldn't worry too much, PC PSU watts are measured the same way as car audio amp watts. (Take the real continuous power it can supply without catching fire, and multiply by the marketing guy's shoe size, or his IQ, whichever is less.)
As others have said, PFC caps won't help, as they mostly correct displacement power factor, and don't much help harmonic power factor. Third harmonic is the usual culprit, as the fundamental currents from the three phases cancel in the neutral wire, but the third harmonic currents add. The other triplen harmonics do too, but the third is usually strongest. All you need to do is use a neutral conductor the same gauge as the phase conductors, and it will handle it safely. It's only undersized neutral wires that cause trouble.
And it's between phase and neutral for 240V! Phase to phase is 415V. If you get this wrong, your next LAN party could be your last.
I was going to measure the voltage anyway once I move into the house, This was so I could plan for it
Registered Member #152
Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
Almost all power supplies today are built with an active PFC circuit or at least a passive choke (in the cheaper ones), so I wouldn't worry about that, unless they bring 3+ year old PCs
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Voltage between phases
