Using the extra voltage inputs

Can the extra two voltage inputs normally used in three phase mode be used in single phase configuration to monitor other voltages?

Also what is the nominal voltage sensing input voltage? I’d be monitoring a 240 volt circuit so, of course, I’d need a transformer with a turns ration double that of the 120 V reference transformer.



I use a Euro 230V transformer to measure 240V in my house. Works fine.

I went back to the manual. I know, I know, RTFM, right? I see the extra voltage inputs are shared with CT inputs 13 and 14 and are configured through those inputs including the phase relationship as needed.

I guess I could have answered my other question myself by looking at the voltage reference transformer on my system. Being 120VAC/9VAC I could have reasoned that what I need for what I’d like to do is get a 240VAC/9VAC transformer.

As always, thank you for a great product.

Here’s a transformer I’m looking at which is available from for sensing 240 VAC. It’s a Triad TCT3-12E07AE.

I’ve not been able to find a decent transformer with a 240V primary and 9V secondary. This Triad transformer has a 240V primary and 10V secondary.

The input voltage divider in the IoTaWatt is 12K/1K about (13:1). Since this transformer is a bit higher than 9V would it be wise to add an extra series resistor externally?

I want to build this into an AC voltage regulator I’m building to monitor the downstream voltage to the load.


That would work.

Not necessary, should be fine.

I got that transformer and am building my system to regulate the line voltage to my heat pump. I just need to make a cable so I can monitor it.

What is the spec for the voltage input jacks and compatible plugs?

The most common size for these coaxial power plugs seems to be 5.5mm X 2.1mm or 5.5mm X 2.5mm. I’ll need to make a custom cable for my equipment and need to know the proper plug size to use.