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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => AC Power and Grounding => Topic started by: Todd Friemuth on April 02, 2018, 07:08:16 pm

Title: Random question about something not audio related
Post by: Todd Friemuth 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.
Title: Re: Random question about something not audio related
Post by: Andrew Broughton 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.
Title: Re: Random question about something not audio related
Post by: Todd Friemuth 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.
Title: Re: Random question about something not audio related
Post by: Jonathan Johnson 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.
Title: Re: Random question about something not audio related
Post by: Tim McCulloch 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?
Title: Re: Random question about something not audio related
Post by: Todd Friemuth 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.
Title: Re: Random question about something not audio related
Post by: Thomas Harkin 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.
Title: Re: Random question about something not audio related
Post by: Kevin Graf 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.
Title: Re: Random question about something not audio related
Post by: John Roberts {JR} 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
Title: Re: Random question about something not audio related
Post by: Mike Sokol 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.   
Title: Re: Random question about something not audio related
Post by: Stephen Swaffer on April 03, 2018, 11:00:24 pm
I may be wrong-but I seriously doubt Hawaii is on the same grid-so that would make it 48  :)
Title: Re: Random question about something not audio related
Post by: Mike Sokol on April 04, 2018, 12:02:46 am
I may be wrong-but I seriously doubt Hawaii is on the same grid-so that would make it 48  :)
OK... details, details. But it appears to be broken up a little more. And no mention of Hawaii: https://en.wikipedia.org/wiki/Continental_U.S._power_transmission_grid

So Texas is indeed on its own grid, but there's a few other major regions.

The electrical grid that powers mainland North America is divided into multiple regions. The Eastern Interconnection and the Western Interconnection are the largest. Three other regions include the Texas Interconnection, the Quebec Interconnection, and the Alaska Interconnection. Each region delivers 60 Hz electrical power. The regions are not directly connected or synchronized to each other, but there are some HVDC interconnections.
Title: Re: Random question about something not audio related
Post by: Steve M Smith on April 04, 2018, 03:08:08 am
Or a genuine Hammond B3.  Synchronous 60Hz motor.  Is the organ on pitch or sharp a few cents?

As I mentioned in another thread yesterday, we should have standardised at 55Hz - tuned to A.  You could check your power with a tuning fork!


Steve.
Title: Re: Random question about something not audio related
Post by: Keith Broughton on April 04, 2018, 03:16:07 am
You could check your power with a tuning fork!


Steve.
Just don't stick your fork in the outlet  ;D
Title: Re: Random question about something not audio related
Post by: Dave Garoutte on April 04, 2018, 03:42:25 pm
Just don't stick your fork in the outlet  ;D
LOL literally!
Title: Re: Random question about something not audio related
Post by: Jonathan Johnson on April 05, 2018, 02:15:09 pm
As I mentioned in another thread yesterday, we should have standardised at 55Hz - tuned to A.  You could check your power with a tuning fork!


Steve.

Just remember, you can tuna fish but you can't teach it to sing.
Title: Re: Random question about something not audio related
Post by: Dave Garoutte on April 05, 2018, 06:52:25 pm
Just remember, you can tuna fish but you can't teach it to sing.
The reason you can't tuna fish is they have too many scales.
Title: Re: Random question about something not audio related
Post by: Mike Sokol on April 05, 2018, 07:35:50 pm
The reason you can't tuna fish is they have too many scales.

Please mako it stop.... :o
Title: Re: Random question about something not audio related
Post by: Art Welter on April 07, 2018, 01:06:17 am
Please mako it stop.... :o
This thread is going to need a sturgeon to get it out of the tank.
Title: Re: Random question about something not audio related
Post by: David Allred on April 07, 2018, 10:40:21 am
Take the microwave to work, or a friend's house that lives far enough away for a week.  Might not tell you much  but it will tell you something.
You will definitely learn how much you rely on a microwave.
Title: Re: Random question about something not audio related
Post by: Todd Friemuth on April 08, 2018, 06:08:27 am
I finally had a chance to revisit this yesterday with a proper meter in hand. I tested the microwave circuit and let the meter stabilize for 30 minutes and I got 60.02 Hz. Moved the meter to the kitchen island circuit and let it stabilize for 30 minutes and got 60.00 Hz. Random outlets around the house all read 60.00, go back to the microwave, back to 60.02. Never did bother pulling the stove out to meter it's circuit.
Title: Re: Random question about something not audio related
Post by: Mike Sokol on April 08, 2018, 06:37:00 am
I finally had a chance to revisit this yesterday with a proper meter in hand. I tested the microwave circuit and let the meter stabilize for 30 minutes and I got 60.02 Hz. Moved the meter to the kitchen island circuit and let it stabilize for 30 minutes and got 60.00 Hz. Random outlets around the house all read 60.00, go back to the microwave, back to 60.02. Never did bother pulling the stove out to meter it's circuit.

At first blush I would say this is impossible, but perhaps there's something else going on that can cause both the clock and meter to run fast. As noted earlier, what if there was noise on the line that could be interpreted as the extra 0.02 Hz? Maybe something creating a 2 or 4 Hz noise pulse on that branch circuit is happening. 
Title: Re: Random question about something not audio related
Post by: Todd Friemuth on April 08, 2018, 10:43:11 am
It did cross my mind that within this same period of time that I've been noticing this issue, that the electric company has been going around installing their "smart electric meters". Is it possible the smart meter could cause this?
Title: Re: Random question about something not audio related
Post by: Jean-Pierre Coetzee on April 08, 2018, 11:57:55 am
It did cross my mind that within this same period of time that I've been noticing this issue, that the electric company has been going around installing their "smart electric meters". Is it possible the smart meter could cause this?

I have heard from HAM radio guys about "smart meter" throwing off tons of harmonics into their systems. This might be the cause of your problem but why it would just be on 1 circuit is beyond me. Maybe there is a cap going in your microwave that is causing the harmonics and is magically on the same circuit as your stove(here in South Africa the stove has to be on its own dedicated 30A circuit but not sure about there) and it's just throwing those two off.
Title: Re: Random question about something not audio related
Post by: John Roberts {JR} on April 08, 2018, 02:24:33 pm
It did cross my mind that within this same period of time that I've been noticing this issue, that the electric company has been going around installing their "smart electric meters". Is it possible the smart meter could cause this?
If you had a scope handy you might see the noise on the mains.

An old school mechanical motor clock could reveal whether it is frequency drift (unlikely) or noise (more likely).

I have used mains frequency for a time base a number of times over the decades. I always filtered it to reduce HF noise issues.

JR

PS: If this is a widespread problem your utility and/or microwave maker may know about it, of course if a new issue they may not have a solution and be ready to talk about it yet.
Title: Re: Random question about something not audio related
Post by: Kevin Maxwell on April 08, 2018, 06:35:56 pm
This thread is going to need a sturgeon to get it out of the tank.

I can't fathom that, it is too deep for me. Did you say that on porpoise?

Somewhat on topic, a presenter I used to work with occasionally, used to say if you had more then one time piece you really didn't know what time it is. The digital clock in my car (part of the radio) keeps on gaining time. I have to keep resetting it or I might actually arrive somewhere on time.
Title: Re: Random question about something not audio related
Post by: Scott Holtzman on April 08, 2018, 08:06:37 pm
I can't fathom that, it is too deep for me. Did you say that on porpoise?

Somewhat on topic, a presenter I used to work with occasionally, used to say if you had more then one time piece you really didn't know what time it is. The digital clock in my car (part of the radio) keeps on gaining time. I have to keep resetting it or I might actually arrive somewhere on time.

I get this, I lead a temporally challenged existence too.  It's amazing that your friends will actually start making accomodations for it after a period of time.

Title: Re: Random question about something not audio related
Post by: Mike Sokol on April 08, 2018, 09:15:41 pm
I get this, I lead a temporally challenged existence too.  It's amazing that your friends will actually start making accomodations for it after a period of time.

My twin brother was always late for dinner, so we told him 6PM for a 6:30 dinner, and we always made it there 5 minutes early.
Title: Re: Random question about something not audio related
Post by: David Allred on April 09, 2018, 10:06:58 am
My twin brother was always late for dinner, so we told him 6PM for a 6:30 dinner, and we always made it there 5 minutes early.

You mean there are 2 of you?!   :)
Title: Re: Random question about something not audio related
Post by: Dave Garoutte on April 09, 2018, 12:46:30 pm
You mean there are 2 of you?!   :)
I hope his name is Ike.
Title: Re: Random question about something not audio related
Post by: Mike Sokol on April 09, 2018, 06:32:50 pm
I hope his name is Ike.

We are a couple of fruits...