This
is a question we have appealed with the CAA. The true induction tachometer uses
a notched wheel (phonic wheel)
This question was referring to a 3 phase AC tachometer.
It
is incorrect to refer to it as an induction tachometer.
Although
the squirrel cage motor that drives the indicator is known as an induction
motor, that does not make it an induction tachometer.