Question

A variable reluctance type tachometer is used to measure angular velocity of a rotating shaft. The shaft is rotating at a constant speed of about 150 rpm. If the tachometer wheel is having 40 teeth then the pulses/ sec indicated by the counter for the given speed is?

• A. 100

Answer 1

The correct option is A 100
$Speed\left(N\right)=\frac{\text{P}}{\text{T}}\times 60$

$\text{N = rpm speed}$

$\text{P =pulses/sec}$

$\text{T = Number of teeth}$

$\therefore$ $\text{Given N = 150 rpm, T =40}$

$\therefore 150=\frac{\text{P}}{40}\times 60$

$P=100pulses/sec$