Triac Motor On/Off Circuit:Load side Interchangeble?

Thread Starter


Joined Aug 21, 2021
You can connect the motor where the green circle is but you cannot connect it where the red cross is.
View attachment 246262
Thanks Albert, I Have a circuit as you described with the motor where the green circle is. The reason I ask is that the voltage drop at 240VAC 3A is 2.4V, which is higher then st micro recommended circuit simulation estimated. The triac is getting hotter then expected for the 5.5k/w heat sink. I should be able to run 11A at 60c ambient but can only run 3-4A


Joined Jan 23, 2018
The main consideration will be the voltage on the triac heat sink and any possible shock hazard possibility. Radiated electrical noise might also be a concern. Or maybe not.