Electricity Quality

sawmill

I have been using an Outback vfx 3524 for the past three years. It appears that in recent months the digital clocks have been showing a greater increase of time gain in a 24 hour period.

Today the microwave died (could have been it's time). The one who must be obeyed has raised questions about the quality of electricity being produced by our solar system.

My Kill A Watt meter shows 59.9 cycles from the grid and the same from the Vfx.

Any comments or suggestions would be appreciated.

Bill

mike95490

Re: Electricity Quality

How close to Area 51 are you ?

Brock

Re: Electricity Quality

Is it tied to the grid? If so it's getting it Hz from the grid anyway. I haven't heard of any having issues, without a good meter like a fluke 87 or better that can min max Hz in 1/10 seconds it might be hard to find out. I would highly doubt the inverter killed the micro, but without more info it's hard to say.

niel

Re: Electricity Quality

temporary minor fluctuations in frequency have occured on the grid, but nothing that would cause what you're seeing that i'm aware of. don't buy that kind of clock and microwave ovens are being cheapened in their quality compared to the previous decade and don't seem to last as long.

as an alternative, buy one clock that is considered atomic (figuritively and not literally) in that it has a small radio receiver in it to pick up broadcasts from the atomic clock in boulder col. with the callsign wwv and set the other clocks to that one. if you're into sw listening then tune in the broadcasts once in a while on 2.5, 5, 10, 15 and 20mhz and readup on utc time and how it compares to your local time.

sawmill

Re: Electricity Quality

I have a stand alone system, not grid tied.

My Vfx feeds a ten circuit transfer switch in order to control my loads.
The digital (2) clocks only gain time when on the inverter and keep correct time on the grid.

I use a WWV connected clock for accurate checking. The Kill A Watt meter shows 59.9 hz on the inverter circuit and 59.9 hz when that circuit is switched to the grid. Minor inverter voltage swings depending on loads, the grid voltage will vary depending on time of day but well within specs.

The time gain is a very minor problem and only mentioned because of concern about the quality of electricity being produced by the Vfx3524.

Mike--since I am in NC I believe you are much closer to area 51.

Neil is probably right about the poor microwave quality and has no relation to inverter output but still doesn't explain clock speed.

niel

Re: Electricity Quality

if you develope any theories to it or actually find out why then please let us know. btw, my kill-a-watt meter also says 59.9hz.

Brock

Re: Electricity Quality

Hey ours is also 59.9 I suppose the entire grid is all connected so it should be the same right?

BB.

Re: Electricity Quality

It looks like the kWhr meter is probably reading 59.9999Hz or something--and not rounding off...

My Xantrex GT 3.0 inverter reads 60.0 Hz 100% of the time (and it has to be accurate--I presume--since it is a regulated function looking at utility frequency).

I think that the 60Hz can droop by a couple 0.01% or so below 60Hz during the day (during heavy loads, summer A/C / pumping seasons, etc.), and then the utility will late at night run it up by a couple 0.01% so that by the end of a 24 hour period the average will be exactly 60.00000000... Hz.

A wiki article (at least a start):

Frequency stabilization of large interconnected power systems allow line-operated clocks to keep accurate time. Network operators will regulate the daily average frequency so that clocks stay within a few seconds of correct time. In practice the nominal frequency is raised or lowered by a specific percentage to maintain synchronization. In the continental European UCTE grid, the deviation between network phase time and UTC is calculated at 08:00 each day in a control center in Switzerland, and the target frequency is then adjusted by up to ±0.02% from 50 Hz as needed, to ensure a long-term frequency average of exactly 3600×24×50 cycles per day is maintained.[14] In North America, whenever the error exceeds 2 seconds for the east, 3 seconds for Texas, or 10 seconds for the west, a correction of ±0.02 Hz (0.033%) is applied. Time error corrections start and end either on the hour or on the half hour.[15][16] A real-time frequency meter for power generation in the United Kingdom is available online.[2] Smaller power systems may not maintain frequency with the same degree of accuracy.


The frequency of large interconnected power distribution systems is tightly regulated so that, over the course of a day, the average frequency is maintained at the nominal value within a few hundred parts per million.[17] While this allows simple electric clocks and motors, based on synchronous electric motors, to keep accurate time, the primary reason for accurate frequency control is to allow the flow of alternating current power from multiple generators through the network to be controlled. The trend in system frequency is a measure of mismatch between demand and generation, and so is a necessary parameter for load control in interconnected systems. Regulation of power system frequency for timekeeping accuracy was not commonplace until after 1926 and the invention of the electric clock driven by a synchronous motor.

-Bill