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| Thread ID: 107817 | 2010-03-02 23:45:00 | Phase Angle - what is it? | Agent_24 (57) | PC World Chat |
| Post ID | Timestamp | Content | User | ||
| 863271 | 2010-03-02 23:45:00 | I'm hoping someone with more electronics knowledge than me can explain what "Phase Angle" is in the context of the mains power supply. We had one of those new digital power meters installed a while back, and while setting it up the technician showed me what it could measure After pressing the button a few times and commenting on the various items he came to one which he called "Phase Angle". He then proceeded to read out the number (I think it was 50-something) and then told me in no uncertain terms "that means your power is sh!t" What does this all mean and why is it sh!t? What causes it? And most importantly, is there a detrimental effect on my computer? :lol: |
Agent_24 (57) | ||
| 863272 | 2010-03-02 23:49:00 | I have to admit I don't have a clue but I am somewhat concerned about smart meters which are not that smart. | Sweep (90) | ||
| 863273 | 2010-03-03 00:24:00 | Apparently it has Bluetooth capability and can theoretically interface with yet-to-be-built washing machines to allow power usage only during off-peak hours to save money or something... I reckon it's just a security hole waiting to be exploited... |
Agent_24 (57) | ||
| 863274 | 2010-03-03 01:17:00 | In an AC circuit like your mains supply, when you are using power the voltage and current rise to a maximum, fall to zero and then reverse to another peak, back to zero, and repeat. Both the current and voltage oscillate at 50 cycles per second in NZ. However, they only very rarely do this synchronously (or in phase), that rare event is said to be when the phase angle is zero. Because this rise and fall is called a cycle it is commonly measured along the time axis in degrees, with 360 deg being the time between the same points in each cycle. The goal of the power supplier (aside from regular price rises) is to deliver a supply that is as close as possible to a zero phase angle; i.e. both voltage and current rising and falling simultaneously. The load you apply to the supply sometimes changes this, it is good to make corrections to ensure you get all the useful power you are paying for. Sounds like you and/or your neighbours need a bit of power factor correction to get the phase angle back where it belongs. | R2x1 (4628) | ||
| 863275 | 2010-03-03 02:12:00 | Nice explanation by R2x1, but I would add that voltage and current are only in phase for resistive loads like heating elements. Anything inductive like a motor, or items with power capacitors in them like fluorescent lights will cause the voltage and current to be out of phase. Equipment with switch-mode power supplies (such as computers) also cause phase errors. The greater the power factor error, the higher your power bill gets, so major plants and office buildings use active power factor correction to maximise efficiency and minimise power costs. Their saving can be quite substantial. It would be unusual for a domestic household to have bad power factor, though some degree of error is pretty much always present. However, your apparent PF is influenced by all the other consumers sharing the same phase on the local supply transformer so there's not much you can do about it. It won't affect your computer at all. Cheers Billy 8-{) |
Billy T (70) | ||
| 863276 | 2010-03-03 04:12:00 | It's so they can justify the doubled power bill when it arrives. Take a google about NZ smart meters, in particular user comments. Seems to be the common theme. |
pctek (84) | ||
| 863277 | 2010-03-03 06:08:00 | billy...do they still use the cap banks to counter the inductive loading by major industries ? that helps to correct bad power factor. |
tweak'e (69) | ||
| 863278 | 2010-03-03 06:18:00 | Time to consider solar? If you borrow $4000 say @ 8%,thats $320 a year. If you save say $50 a month,that is a saving of $600. |
Cicero (40) | ||
| 863279 | 2010-03-03 07:02:00 | It's so they can justify the doubled power bill when it arrives . . . Seems to be the common theme . For the company that owns the meter, isn't that the smart thing to do? ;) |
R2x1 (4628) | ||
| 863280 | 2010-03-03 07:36:00 | The greater the power factor error, the higher your power bill gets, so major plants and office buildings use active power factor correction to maximise efficiency and minimise power costs . Their saving can be quite substantial . Is that true for domestic users here? The traditional metering has been kWh with no penalty for low power factor . |
PaulD (232) | ||
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