Im working on a AC triac motor controller for universal motors For this I want to measure the motor current and the speed. For the speed the motor provides a tacho-signal. To isolate the measurement I will use a current sense transformer for the motor current before feeding the signal to the ADC. But what I am not sure about is wether an isolation of the tachometer signals are necessary. I do not have any documentation of the motor but i guess it uses a hall sensor for providing the tacho signal. So in my opinion no isolation is needed and I can feed the signal directly to the ADC but I want to make sure I am right.
So my question is:
What is your opinion? Do I need an Isolation for the tacho signals?
thanks in advance