ECN Forum
Posted By: ThinkGood 60Hz +/- ??? - 02/21/03 06:40 PM
On my residential electric, I used a DMM to check the frequency. One leg read 60Hz, the other read 61Hz. I believe that voltage can run anywhere from 110 to 125 VAC. Is there a particular range for the frequency as well? I don't think that one Hz will matter very much, but it seems strange that one is 60 and one is 61.
Posted By: C-H Re: 60Hz +/- ??? - 02/21/03 06:59 PM
>One leg read 60Hz, the other read 61Hz.

Impossible. That would require you to be connected to two different power grids.

>Is there a particular range for the frequency as well?

Yes, and it is probably less than 1 Hz. For Europe it's +/-1%, but for the main European grid it's .1 Hz or better, AFAIK. I cannot imagine that the American grid would be any worse.
Posted By: Pearlfish Re: 60Hz +/- ??? - 02/21/03 07:09 PM
the 1.6% difference your seeing between readings is just the margin-of-error built into your meter. Some meters have higher tolerences than others. Your readings could be affected by anything from ambient temperatures/humidity or your battery strength or how many times you dropped your meter.
Posted By: Trumpy Re: 60Hz +/- ??? - 02/24/03 05:13 AM
Pearlfish,
Good point, mate!. [Linked Image]
Meter accuracy is very important when taking frequency measurements, a lot more so than on voltage measurements.
I would personally only use an Analouge meter, built for the purpose. [Linked Image]
Posted By: Admin Re: 60Hz +/- ??? - 02/25/03 04:41 AM
Posted for Bjarney:
Quote
Electric utilities worldwide use GPS clocks for system frequency tracking, that are routinely accurate to 0.000 000 05 seconds. In the US, regional electric coordinating councils take frequency accuracy very seriously, for not doing so would make it very hard to conduct bulk-power transactions. {It takes electricity about 0.000 000 001 seconds to travel 1 foot through cable.}

Read over your meter’s manual and consider its published accuracy figures—it’s likely there is some measurement error.

- Bjarney
Posted By: Andre M Re: 60Hz +/- ??? - 02/25/03 09:42 PM
Since long time, line frequency (60Hz) was used to drive street and house clocks in America.
Still some grids in Third World has synchonized (between power plants) but not stabilized frequency, and their line powered clocks lag 10-20 minutes per day.
Of course, no problem with battery, quartz stabilized clocks.
Andre
Posted By: pauluk Re: 60Hz +/- ??? - 02/26/03 12:40 AM
I'd say it's the display resolution of the meter. Applied voltage shouldn't affect the frequency readout, but on some types a minor difference in voltage between the two legs could cause the display counter to be out by one count on the two readings.
Posted By: sparky66wv Re: 60Hz +/- ??? - 02/26/03 02:06 AM
(Ahem) Check Check test test *tap tap tap* Is this thing on?

Mods feel free to delete, apparently I'm having no problems posting here...

[Linked Image]

[This message has been edited by sparky66wv (edited 02-25-2003).]
Posted By: Sandro Re: 60Hz +/- ??? - 02/26/03 03:17 AM
Interesting topic.... when doing field installations, I still come across specs on wiring for 60hz and wiring for 50hz. When and where would I come across 50hz frequency? Or is dual frequency rating a standard manufacturing practice?
Posted By: SvenNYC Re: 60Hz +/- ??? - 03/04/03 04:30 AM
Sandro, 50 hertz is usually used in Europe, Asia, Africa and parts of South America (Argentina and Chile, for ex.).

I don't know where it would be used here in North America and the northern part of South America (Colombia, Venezuela, Ecuador). I think all power companies in this area generate 60 hertz.

Wonder why the wiring would be different...probably something internal with the equipment you're wiring? A frequency dependent component like a timing chip, perhaps?

(puzzled)
Posted By: Admin Re: 60Hz +/- ??? - 03/04/03 06:10 AM
Posted for Bjarney:
Quote
One short 50Hz versus 60Hz discussion…
http://www.ieee.org/organizations/history_center/faqs.html#60%20cycles

In the US, the Los Angeles area switched from 50 to 60Hz in the mid 1930s.
Posted By: pauluk Re: 60Hz +/- ??? - 03/04/03 03:41 PM
Quote
I don't know where it would be used here in North America

Several Caribbean nations use 50Hz power, mostly those which were/are colonies of the UK or other European countries, e.g. Barbados, Jamaica (120V), Guadeloupe, Martinique, St. Lucia, Dominica (220-240V).

The frequency will affect timing devices that are synchronized to the supply, as has already been mentioned, but there are other items which can be affected. The ballast in a fluorescent light fixture is an example. The inductive reactance is dependent upon the applied frewuency, so the current will be different when run on the "wrong" supply. Similar constraints apply to transformers: Although not a problem for small xfmrs in appliances, it can be significant for a big power xfmr (i.e. multi kVa).
Posted By: C-H Re: 60Hz +/- ??? - 03/04/03 04:27 PM
Quote

Similar constraints apply to transformers: Although not a problem for small xfmrs in appliances

Ahem... This is not what I have been told. To cut cost on small transformers, the iron core is made as small as possible which means that the headroom is so small that a 60Hz core reaches saturation when used on 50Hz. There are reports from travellers confirming that overheating is a problem.
Posted By: Sandro Re: 60Hz +/- ??? - 03/05/03 04:09 AM
Sven...

Allow me to un-confuse you. I was wiring a motor contactor from a manufacturer "ABB" and written write on the specs of the contactor were 50hz specs, and 60hz specs. So, judging from the responses on this forum I figure this contactor from ABB is sold worldwide.
Posted By: Sean WB Re: 60Hz +/- ??? - 03/05/03 06:31 AM
thinkgood, were you just curious? why would you sine/sync a res electric service? maybe setting a gen set?the unspoken laws of electricity. they are truly fascinating , mathematical mysteries. i have seen these meters only when testing backup/emergency power gen sets at hospitals etc.to ensure synchronization between sine waves in service power and backup power. Because the damage that may incur when applying voltage that is lagging or leading the service (in cycles)can be incredibly disastrous to motors.
besides , the kind of meter it takes to read the frequencies accurately are very very expensive and come in clean, padded, fancy, drop proof, shock proof boxes LOL
© ECN Electrical Forums