Amplitude Posted September 4 Share Posted September 4 I just today installed a pro em-50 to monitor a home with 2 large air conditioning units. The unit is working properly and is connected to the cloud, but unfortunately due to the quirk of the north American power grid it does not accurately calculate the power of the circuits being monitored: it accurately measures the voltage and current of the wire that the ct is clamped onto, but remember that in north America due to the standard usage of a "split-phase" distribution system in residential environments, it is measuring the entire CURRENT of the circuit, but only HALF of the voltage (if the circuit is 1-ph, 240 v). So while it correctly reads the current of the Air conditioning units, it is calculating consumption as though they are 120 v devices when they are, in fact, 240 v devices. Could I fix this issue by writing a script and simply multiplying the measured voltage by 2 and returning the value to the register? Or installing a shelly PM in the circuit at the load center, from L1-L2, and then using the measured voltage from the pm to insert into the script? Even if I can't visualize the data in the app I would like to accurately record the data to somewhere for analysis. Quote Link to comment Share on other sites More sharing options...
Members thgoebel Posted September 4 Members Share Posted September 4 Using a separate Shelly pro EM-50 to monitor the 220V devices (voltage measurement between the two live wires) and another EM-50 for the 110V appliances (measuring voltage between live and neutral) will solve the issue. Quote Link to comment Share on other sites More sharing options...
Amplitude Posted September 5 Author Share Posted September 5 22 hours ago, thgoebel said: Using a separate Shelly pro EM-50 to monitor the 220V devices (voltage measurement between the two live wires) and another EM-50 for the 110V appliances (measuring voltage between live and neutral) will solve the issue. Can you elaborate on this? I have the em-50 currently exclusively monitoring 240-volt appliances. I have it wired and connected correctly. I also noticed that the ct's of both channels need to be on the same phase conductor, otherwise one will read a negative value, regardless of how the ct is oriented with respect to the grid-load direction Quote Link to comment Share on other sites More sharing options...
Members thgoebel Posted September 5 Members Share Posted September 5 You‘re welcome: 1 Quote Link to comment Share on other sites More sharing options...
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