I just installed a Aeon Labs Gen5 ZW095 Home Energy Meter (HEM).
There are 2 clamps as expected these go on the 2 phases of power coming into the home.
Then there is just 1 wall plug which is connected to one of the 2 phases. This powers the unit and I assume measures the voltage.
But there is a child device for the other phase voltage.
How would that work?
What are the physics behind it?
Are they just assuming the same voltage on both phases?
Without a physical wire connected to the other phase they can't possibly know the voltage.
My Sense HEM on the other hand wires into both phases which then obviously can measure the 2 voltages accurately.
I'm thinking if I have a big motor on 1 phase (or even just turn on a hair dryer) then that phase voltage will droop and the readings will be off. There is no spec for the "accuracy" that I see in the doc - just a range of 0A-200A so that doesn't inspire confidence.
https://drzwave.blog/
There are 2 clamps as expected these go on the 2 phases of power coming into the home.
Then there is just 1 wall plug which is connected to one of the 2 phases. This powers the unit and I assume measures the voltage.
But there is a child device for the other phase voltage.
How would that work?
What are the physics behind it?
Are they just assuming the same voltage on both phases?
Without a physical wire connected to the other phase they can't possibly know the voltage.
My Sense HEM on the other hand wires into both phases which then obviously can measure the 2 voltages accurately.
I'm thinking if I have a big motor on 1 phase (or even just turn on a hair dryer) then that phase voltage will droop and the readings will be off. There is no spec for the "accuracy" that I see in the doc - just a range of 0A-200A so that doesn't inspire confidence.
https://drzwave.blog/
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