Do these make sense?

gar

Senior Member
190827-1512 EDT

Back to power and energy monitoring.

A tool to measure and record power and energy vs time is useful for learning, research, and troubleshooting.

To use such a tool to try to know what specific load is on and its power consumption form the main panel location is unreasonable in many cases. I would really say in most cases.

To be useful I think multiple units are required.

Probably what i need is 22 current sensors, and scanning of these. In my main panel I have a plugin main fuse, seven 2 pole and six 1 pole breakers. At a few times per day I may want a general idea of what is on. Has a heater been left on, are some large light loads on, etc?

With smart meters the power company provides adequate information on my total daily usage. I also get natural gas usage information. Water department provides water use.

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synchro

Senior Member
190827-1451 EDT

There are devices called resolvers that have two outputs. These can be described as two phase devices. Their outputs are of identical frequency, waveforms close to each other, and approximately the same amplitude. However, the phase angle of one output relative to the other can be anywhere between 0 and 360 degrees depending the resolver input shaft angle. Should these be a two phase device at only some specific angle, not reasonable?
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Given my forum username I figured I should chime in that there are also electrical/shaft angle transducers called synchros that have a single phase input and 3 outputs. The amplitude of the 3 AC outputs is a function of the shaft angle. Synchros and resolvers have been used since WWII, and they still are used in some high reliability applications.
 

kwired

Electron manager
Not a metering expert by any means, but have seen single phase 120/240 metering several times where they only use one CT and run each ungrounded "line" in opposite directions through the CT. Same direction cancels, opposite direction is additive, just like it would be with a clamp on ammeter.
 

gar

Senior Member
190827-2133 EDT

kwired:

That works.

Usually can not do in a main panel from a space and current transformer size perspective.

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