I'm trying to automate an exhaust fan by using this ESPHome-driven relay:
I've got the relay setup working and now I'm puzzling over the actual AC motor control unit. The unit is Sentera STR-1. The transformer inside is STC-1-10L10. The unit has a rotary switch (Gottak GTK 46RCTH), which basically shorts different paths to the transformer to get the required voltage (if I understand it correctly).
I think that the lower left terminal on this is connected to the coloured wires in the top row in different positions. Here in this gif I cycle through all knob positions from OFF to 1 to 5 and you can see the mechanics behind the switching – the terminals are connected to the copper plate when the knob is turned. The plan is to connect wires to the appropriate terminal/rotary knob terminals and let the ESPHome switching do the magic.
However, before I blow up my motor or the relay, I want to ask:
What happens if I energize multiple inputs (e.g. 80V and 110V) on the transformer at the same time?
I'm using the interlock feature provided by ESPHome switch component. The ESPHome documentation has an angry red box warning that the software interlock might fail. I'm not sure what would happen with the relay/motor then. Hence the question.
Here's an image of what I think the current scheme looks like on the top, and what I would like to do on the bottom: (Disclaimer: the schematics are probably wrong, but I hope they give an idea of what I'm trying to do) Sorry for butchering the schematic, but several online tools didn't support all the necessary features, so I did an "MS Paint" on it. I hope it's understandable.
Ideally, I would appreciate two answers:
- Would the transformer blow up if the interlock feature fails (it might fail momentarily – for a few dozen milliseconds, perhaps).
- What would be a proper, reasonably cheap solution instead of separate relays?