Author Topic: Monitor Three phases (not triphased load)  (Read 8785 times)

xtrader07

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Monitor Three phases (not triphased load)
« on: April 09, 2011, 12:19:18 PM »
If we want to monitor three phases (not a triphased load): in the distribution board in the house we have 3 phases + neutral, all the loads are monophased and take 120 between one phase and the neutral.
I purchased a TED 5000 with an additional MUT. And I need to know how to make the connection and the measurement since in the instruction manual is not explained. Thanks

vanhook2

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Re: Monitor Three phases (not triphased load)
« Reply #1 on: April 10, 2011, 02:37:37 AM »
Lead, follow or get out of the way!!!
Do not listen to the Muppets

SherlockOhms

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Re: Monitor Three phases (not triphased load)
« Reply #2 on: April 11, 2011, 04:31:11 AM »
You would need to monitor them as 120 loads with one CT only.

TEDSupport6

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Re: Monitor Three phases (not triphased load)
« Reply #3 on: May 13, 2011, 07:47:15 AM »
We currently have our 3-phase TED in beta testing (sorry, no testers are needed at this time). The 3-phase model will be released later this year, however no release is currently set. More information will be posted on the website once it becomes available.

Mr Mohon

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Re: Monitor Three phases (not triphased load)
« Reply #4 on: May 13, 2011, 11:50:04 AM »
What about a wireless TED? Are you guys working on anything like that. One that will allow the MTU's and the Gateway talk wirelessly and not through the power lines? If there were one like this then there would not be PLC noise.
TED 5003-C
MTU 1 = House Sub Panel 1 = Load
MTU 2 = House Sub Panel 2 = Load
MTU 3 = Guest House Sub panel = Stand Alone

TEDSupport6

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Re: Monitor Three phases (not triphased load)
« Reply #5 on: May 18, 2011, 10:24:14 AM »
What about a wireless TED? Are you guys working on anything like that. One that will allow the MTU's and the Gateway talk wirelessly and not through the power lines? If there were one like this then there would not be PLC noise.

We don't have any plans to develop a wireless TED at this time, however our engineers are always looking into ways they can make TED better and more efficient. Thank you for your input!

jrgrant

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Re: Availability
« Reply #6 on: May 20, 2011, 07:40:13 AM »
...
"If you have 3-phase or 230 V 50Hz electrical services, TED 5000 will not work.  We are working on these.
Energy, Inc. is currently developing a 3-phase unit that is expected to be available in April 2011."
...
My condo distributes two legs of a three phase system to each unit.  I look forward to being able to install a three phase TED to monitor my electric energy usage.
Two legs of a three-phase system is single phase, not three phase.  You may be getting 120/208 3 wire (not likely), but even so it would still be single phase and TED should work just fine.

rotus8

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Re: Availability
« Reply #7 on: May 20, 2011, 08:43:54 AM »
Two legs of a three-phase system is single phase, not three phase.  You may be getting 120/208 3 wire (not likely), but even so it would still be single phase and TED should work just fine.
It may look like single phase, but the two legs' phase angle is 120 degrees, rather than the 180 that TED expects. This will cause incorrect power factor computation, and therefore inaccurate power readings.

jrgrant

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Re: Availability
« Reply #8 on: May 20, 2011, 09:58:30 AM »
Two legs of a three-phase system is single phase, not three phase.  You may be getting 120/208 3 wire (not likely), but even so it would still be single phase and TED should work just fine.
It may look like single phase, but the two legs' phase angle is 120 degrees, rather than the 180 that TED expects. This will cause incorrect power factor computation, and therefore inaccurate power readings.
Yes, in a three phase power system the three phasors have a phase angle of 120 degrees.  However, when you only have two points of reference (the two legs) there's no way to tell what the absolute phase angle is, only the relative phase angle between the voltage phasor and the current phasor.  Again, for a residential system you are most likely being supplied with 120/240 3-wire, which is a delta configuration (vs. Y configured which would be 120/208 in the US) on the secondary.  In that circumstance, there is even less to worry about since the neutral is tied to the center of the delta secondary which make the two legs appear as 180 out with respect to each other as viewed from the neutral point.

rotus8

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Re: Availability
« Reply #9 on: May 20, 2011, 12:12:20 PM »
Two legs of a three-phase system is single phase, not three phase.  You may be getting 120/208 3 wire (not likely), but even so it would still be single phase and TED should work just fine.
It may look like single phase, but the two legs' phase angle is 120 degrees, rather than the 180 that TED expects. This will cause incorrect power factor computation, and therefore inaccurate power readings.
Yes, in a three phase power system the three phasors have a phase angle of 120 degrees.  However, when you only have two points of reference (the two legs) there's no way to tell what the absolute phase angle is, only the relative phase angle between the voltage phasor and the current phasor.  Again, for a residential system you are most likely being supplied with 120/240 3-wire, which is a delta configuration (vs. Y configured which would be 120/208 in the US) on the secondary.  In that circumstance, there is even less to worry about since the neutral is tied to the center of the delta secondary which make the two legs appear as 180 out with respect to each other as viewed from the neutral point.
Both questioners in this thread stated pretty clearly that they have three phase power coming in. I wouldn't presume they are wrong, but instead explain how the system works and let them draw their own conclusions. If the two legs are referenced to the neutral they will show up in TED as 120 degrees apart as it also uses the neutral for a reference.

I do agree that this is a weird configuration as any 220 equipment such as a dryer will only see 208 when connected across the legs.

TEDSupport6

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Re: Monitor Three phases (not triphased load)
« Reply #10 on: May 23, 2011, 07:57:29 AM »
The specifications page link above has been updated; I apologize that it was not corrected sooner. As I mentioned above, our 3-phase model is currently in beta testing, which directly affects the timeline on which the model is produced and released. More information will be made available as soon as there are more definite details. Thanks to all of you who are waiting patiently for the release!

TEDSupport6

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Re: Monitor Three phases (not triphased load)
« Reply #11 on: June 07, 2011, 11:17:48 PM »
That link has been updated as well.