I've been cursed with one of these new septic systems with an aerator motor, and it's having one issue after another. I need some way to monitor the amount of current the motor is drawing, and have that graphed out. I bought a Tuya PC31 from Amazon, which works on the Smart Life app, and it will show the current in the live view, but the graphing only shows total power used. I need something that I can specifically graph the current.
I know there are smart outlets, but this has to fit inside the control box. With the Tuya device and it's clamps, there's about no left for air inside the box, so I don't have enough room to add plugs to the wires to use a regular smart plug. There are ones that have a cord on either end, and I'm perfectly comfortable with cutting the plug and outlet ends off, and splicing that in. That would integrate with Hubitat, but I want to make sure I can set up a graph specifically for current, otherwise there's no point in buying it.
Yes. The motor is controlled by the control panel, but the control panel and motor each have their own disconnect boxes, with their own home runs to the breaker box, so I can put whatever device in the disconnect box for the motor, always have power that far, but still monitor current on just that line.
But, in the disconnect box, there still isn't enough room to put plugs on the wires.
Maybe it’s my lack of familiarity with your motor or the Tuya plug you tried.
But why do you have to track current directly?
Are you maybe referring to energy (not power) when you say “total power?” i.e. power over a period of time, like a kilowatt-hour.
I could see how that would not be helpful if you’re looking for max and min (instantaneous) power draws over a period of time, but the smartlife app may not give you that option.
I think essentially any plug that’s compatible with Hubitat and has the capability for power monitoring can give you the info you need.
Depending on your graphing needs, Hubitat has some limited tools, or there are more robust graphing solutions that can also integrate with Hubitat to take the power reporting data generated by a smart plug and create more complex graphs.
If the motor is going bad, it will start to draw more than it's rated current, which is 4 amps. But, if it's happily drawing 4 amps, other than the inrush current when it starts up, then the motor is fine, and that tells me the panel is going bad. With a graph of the current, I can see if the current suddenly went up when the panel alarm starts going off, which tells me it's the motor, most, likely the bearings wearing out on it. If the current stays steady on the graph when the alarm goes off, then it's the panel, because the panel has no way to know that anything is wrong with the motor other than the current goes way too high or cuts out, so that would mean the panel is alarming when nothing is wrong.
But it's not. It's averaging out the power that was used in that time. The motor uses 480 watts while running, and it's half hour on, half hour off. So for easy math, that's a quarter KwH. But, when a motor turns on, it will have a small burst of current to get it going. The graph here does not show that. In fact, it's showing as a half sine wave, where it curves up to the peak power used, then curves back down. I know for a fact that motor is not just slowing starting up and slowing winding down. I need the fraph to show me the exact current being used at any one time.
Locked Rotor Amps (what you are referring to) should occur for a fraction of a second. I can capture it with a Klein clamp multimeter. But even my Sense energy monitor, which samples at 1 MHz (i.e. 1 million events per second) fails to capture it.
I believe the key here is what unit of time are you looking for?
As @aaiyar said, if you need resolution well below one second, I don’t think there’s any device intended for home automation usage that would come even close to meeting that need.
It doesn’t really matter whether you want to see current in amps or power in watts.
Just and update. I did find something to do what I needed. Shelly has a monitor, the Wave PM Mini. I was able to graph out the wattage over time, not just an average, but, OK, I can work with watts on the graph. And I was able to see that the motor would run fine, then just start shooting up, before the system shut it down.
But, I do have one question. I know for a fact that the motor was drawing 3.8-4 amps, so that's 456-480 watts. The Shelly shows it was at 242-245 watts. When setting it up, that Shelly device is not on the list, so I tried a couple, and the Minoston Mini Power Meter plug was the only one that would allow it to show anything, but it doesn't have a setting for offset. Does anyone know if there is code that can be uploaded for this Shelly device?
Is IotaWatt still being manufactured / sold? I've seen several references to them here in this community so I went to go check them out and it looks like they may have ended retail sales?
