20230215_iotamsgs.txt (25.0 KB)
The readings were just fine in the beginning. One room has an electrically heated floor and indicated the correct power consumption (240V/60Hz) with a PF of 1.00. Lately it’s indicated power consumption with nasty power factors EVEN WHEN THE FLOOR IS OFF. I don’t get it.
I check to ensure that the CTs are securely closed, and I compared to a separate device to make sure that power was truly off.
Today we were on generator power for a while and the the reading were wildly off. There is a walk-in cooler on the monitored sub-panel, and it’s readings have also become wonky.
Any insights? I really want to depend on this system for accurate readings so that I have numbers for operating costs.
I have had no reports of wonkyness.
You haven’t given much to go on. I have had Iotawatt(s) for years. In my experience wonky measurements are typically caused by a wonky install. You haven’t provided and pictures or indicated what you are using for CTs and what you are using for a VT.
Is the wonkyness limited to a single circuit? If swap the channels and see what happens. Then swap the CTs. That will tell you if the wonkyness is in the CT, the placement of the CT, the wiring, or perhaps a single input channel of the Iotawatt.
Exactly how much power is it reporting?
Where is the graph?
Not isolated to a single circuit. I monitor three 240V sub-panels.
- One panel starts getting power factors in the .5-.6 range, then drifts back to 1.0. All that’s running is a 240V space heater and water heater.
- One panel shows a load even when I open the breaker.s (Electric floor and down stream walk-in cooler) Roughly 3kW
- One panel has been pretty normal since only a 30W ceiling fan when not in use. (My wife’s studio with propane heat)
50A CTs (six total) for three panels. AcuCT-H040-50
The major disruption is when I’m on generator. It’s a high speed generator and they are given to a lot of harmonics. Could that noise have messed with the IotaWatt processor?
I’m adding two graphs for the day. I was in the orchard when the power failed, so there’s a period of no readings before I got the generator started. I was busy with a lot of things going on, so I regret that I couldn’t capture live screen displays. I hope that overlaying the wattage and PF plots gives some clarity. Please note that the sink room load is very resistive with only a wall fan and the fan in the electric heater.
I can accept that this could be a power quality issue. My #1 priority is to keep rooms warm and the cooler cold.
I suspect it could.
I search my historic data (still in IotaWatt:
Looks like there was a power failure in mid January 2021 that was quite long. I have an automatic standby generator, so it starts automatically 20-30s after the power goes out. You can see the PF is wonky during that time. I know my generator emits a lot of harmonic distortion, so much that some electronics from the late 70’s/early 80’s can’t handle it and I have to unplug them after the normal power comes back. More modern equipment handles it fine. But, you can see that Iotawatt gets confused when on generator power. I never noticed this before, because I never looked at PF before. It looks like your generator isn’t much worse than mine in terms of out putting clean power. I have a big enough generator that I don’t need to worry about over taxing it. As you can see from the voltage, it has a lot of room to go down before there would be an issue (also its voltage regulator is not so good as I can’t get it low enough when there is light load).
If you are only seeing the issue when on generator, it is likely your generator is just too noisy to work well. The monitoring system I was using before was much worse on generator. I suspect there might be some way to make something that works better, but I don’t know of anything off the shelf that does better.
It is not necessary to capture a live screen display. Iotawatt has a great data storage system, so the same data is still there.
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Better graph of what IotaWatt can do. The first graph makes it look like IotaWatt can’t handle my generator at all. That is because MainA is on the main panel before the generator so there was no power in use, just noise on the circuit.
This graph shows the CT on the sub panel that is powered by the generator. The numbers all look reasonable to me, with little difference between generator and prime power.
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Am I correct in understanding you were on grid power until about 12:30 and then on generator after 14:00?
In both graphs, I don’t see a big difference between grid and generator. Whatever barrel is, it cycles frequently but the PF stays in the high .90’s. The sink graph has a several kW component that short cycles frequently and has a pf close to unity. When it’s at baseline of probably 50Watts or so, the PF is about .90. There is some other 100Watt or so load that shows up during the gaps tht has a PF around 0.70. All of that is about the same morning and afternoon.
Where is the plot of that?
I think you may be mistaken.
As above, I don’t see any issues with the generator. It looks about the same as on grid. What are you looking at that qualifies as a major disruption?
Harmonics or other bad power will not cause the IoTaWatt processor to make repeated mistakes. Computers don’t work like that. It could cause a restart, but not errors or miscalculations. I see some power fail restarts in your message log, but they seem to be associated with actual grid failure and generator startup. After that it seems to have run without incident.
