Question

A variable reluctance type tachometer has 60 rotor slots. If the counter records 3600 counts per second, then the speed is:

• A. 60 rpm
• B. 360 rpm
• C. 1800 rpm
• D. 3600 rpm

Hint:

To calculate the speed of a tachometer, divide the number of counts per second by the number of rotor slots. This gives the speed in revolutions per minute (rpm).

Answer 1

The Correct Option is D

For a variable reluctance tachometer, the number of rotor slots determines how many counts are recorded per revolution. The speed is calculated by dividing the total number of counts per second by the number of rotor slots.
Given:
- Number of rotor slots = 60
- Counter records 3600 counts per second
The speed is given by: \[ \text{Speed (in rpm)} = \frac{\text{Counter readings per second}}{\text{Number of rotor slots}} = \frac{3600}{60} = 60 \, \text{rpm} \] Thus, the speed of the tachometer is 3600 rpm.