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Author Topic: Random question about something not audio related  (Read 1342 times)

Todd Friemuth

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Random question about something not audio related
« on: April 02, 2018, 07:08:16 pm »

I have noticed recently, that the clock on both my microwave and oven have been running fast. They are on two separate circuits of a 200a panel. Everything else in my house (DVR, TV's, computers, etc) get their clocking from the internet I assume. I've noticed this since the time has changed. About once a week I have to reset the microwave and stove and back them up about 5 mins in reference to the actual time. I haven't metered the frequency yet as I don't have a meter at home that does Hz.

With all that said, is it possible that could be any indication that the transformer serving my house is about to go, or what else can the hive mind suggest I investigate that may cause this situation?

Thanks in advance.
Todd.
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Andrew Broughton

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Re: Random question about something not audio related
« Reply #1 on: April 02, 2018, 07:22:38 pm »

Digital clocks on the Microwave and Oven? They'll be unaffected by power other than to stop working when there isn't any.
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Todd Friemuth

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Re: Random question about something not audio related
« Reply #2 on: April 02, 2018, 07:29:24 pm »

Yes, both clocks are digital. They both keep exact time in reference to each other, however they both end up running about 5 minutes fast per week compared to my cell phone or the tv or anything battery operated in my house. The microwave and stove are two separate units on two separate circuits.
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Jonathan Johnson

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Re: Random question about something not audio related
« Reply #3 on: April 02, 2018, 07:34:54 pm »

I have noticed recently, that the clock on both my microwave and oven have been running fast. They are on two separate circuits of a 200a panel. Everything else in my house (DVR, TV's, computers, etc) get their clocking from the internet I assume. I've noticed this since the time has changed. About once a week I have to reset the microwave and stove and back them up about 5 mins in reference to the actual time. I haven't metered the frequency yet as I don't have a meter at home that does Hz.

With all that said, is it possible that could be any indication that the transformer serving my house is about to go, or what else can the hive mind suggest I investigate that may cause this situation?

Thanks in advance.
Todd.

Some line-powered digital clocks do indeed get their "sync" from the 60 Hz (50 Hz in Europe) line frequency. Not all of them use an independent oscillator.

If this is the case, it seems very odd to me that they would gain or lose time, because the line frequency of the power grid is normally very very stable; it's regulated with atomic clocks. It's awfully hard to change the speed of hundreds of tons of phase-locked rotating mass.

On the other hand, I suppose it's possible that somehow you're not even connected to the larger grid, and your neighborhood is being fed by a single generating station not far from where you are. That would be a bad situation, because it's not easy to bring an out-of-phase portion of a grid back into the main grid. There again, you've got an enormous amount of rotating mass to bring into phase with the rest of the grid before you connect it, and you don't want to push the frequency too far off of target or you can damage customer equipment.

There are 10,080 minutes in a week. 5 minutes of variation in that time is about 0.05%. To gain five minutes in a week, the frequency would have to be around 60.03 Hz.

For a poor-man's frequency meter, get an analog, line-powered motorized clock with a sweep second hand. Using a quartz-regulated watch or clock with a sweep second hand, compare the two after several hours to see how much they are off and do the math.

(Good luck finding a line-powered motorized clock. They are pretty much obsolete.)

A call to your electric utility may be in order.
« Last Edit: April 02, 2018, 07:40:59 pm by Jonathan Johnson »
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Tim McCulloch

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Re: Random question about something not audio related
« Reply #4 on: April 02, 2018, 07:53:39 pm »

Some line-powered digital clocks do indeed get their "sync" from the 60 Hz (50 Hz in Europe) line frequency. Not all of them use an independent oscillator.

If this is the case, it seems very odd to me that they would gain or lose time, because the line frequency of the power grid is normally very very stable; it's regulated with atomic clocks. It's awfully hard to change the speed of hundreds of tons of phase-locked rotating mass.

On the other hand, I suppose it's possible that somehow you're not even connected to the larger grid, and your neighborhood is being fed by a single generating station not far from where you are. That would be a bad situation, because it's not easy to bring an out-of-phase portion of a grid back into the main grid. There again, you've got an enormous amount of rotating mass to bring into phase with the rest of the grid before you connect it, and you don't want to push the frequency too far off of target or you can damage customer equipment.

There are 10,080 minutes in a week. 5 minutes of variation in that time is about 0.05%. To gain five minutes in a week, the frequency would have to be around 60.03 Hz.

For a poor-man's frequency meter, get an analog, line-powered motorized clock with a sweep second hand. Using a quartz-regulated watch or clock with a sweep second hand, compare the two after several hours to see how much they are off and do the math.

(Good luck finding a line-powered motorized clock. They are pretty much obsolete.)

A call to your electric utility may be in order.

Or a genuine Hammond B3.  Synchronous 60Hz motor.  Is the organ on pitch or sharp a few cents?
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Todd Friemuth

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Re: Random question about something not audio related
« Reply #5 on: April 02, 2018, 08:29:15 pm »

Or a genuine Hammond B3.  Synchronous 60Hz motor.  Is the organ on pitch or sharp a few cents?

I think I'll grab a meter from the shop tomorrow. The meter fits in my Honda a little easier.
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Thomas Harkin

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Re: Random question about something not audio related
« Reply #6 on: April 03, 2018, 08:25:34 am »

I have noticed recently, that the clock on both my microwave and oven have been running fast. They are on two separate circuits of a 200a panel. Everything else in my house (DVR, TV's, computers, etc) get their clocking from the internet I assume. I've noticed this since the time has changed. About once a week I have to reset the microwave and stove and back them up about 5 mins in reference to the actual time. I haven't metered the frequency yet as I don't have a meter at home that does Hz.

With all that said, is it possible that could be any indication that the transformer serving my house is about to go, or what else can the hive mind suggest I investigate that may cause this situation?

Thanks in advance.
Todd.

Google, "clocks slow in europe" for an interesting read.
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Kevin Graf

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Re: Random question about something not audio related
« Reply #7 on: April 03, 2018, 09:08:45 am »

Primitive digital clocks used the zero crossing of the AC line to keep time. So noise spikes would also count as zero crossings and cause the clock to run fast.
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John Roberts {JR}

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Re: Random question about something not audio related
« Reply #8 on: April 03, 2018, 10:31:46 am »

Many hand held vom have frequency counters but I don't know how accurate they are.

Noise is more likely than generator frequency off, but 5min a week is something like 0.05%

We take the accuracy of modern clocks for granted.

JR
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Mike Sokol

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Re: Random question about something not audio related
« Reply #9 on: April 03, 2018, 10:52:14 pm »

On the other hand, I suppose it's possible that somehow you're not even connected to the larger grid, and your neighborhood is being fed by a single generating station not far from where you are. That would be a bad situation, because it's not easy to bring an out-of-phase portion of a grid back into the main grid. There again, you've got an enormous amount of rotating mass to bring into phase with the rest of the grid before you connect it, and you don't want to push the frequency too far off of target or you can damage customer equipment.
IIRC almost the entire USA grid is phase locked at 60-Hz together, allowing any sort of cross connecting power between generators in different states. It's actually only 49 states since Texas is on it's own grid. So unless your two fast running clocks have a Texas connection and your other clocks are on the USA grid, I don't see how there could be any clock gain when everything in your house is on the same grid frequency.   
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