Working Principle of Mechanical Tachometers or Counters

Working Principle of Mechanical Tachometers or Counters Points : Working Principle of Mechanical Tachometers or Counters Basically a mechanical tachometer consists of three wheels as shown. Its operating principle is illustrated in the fig. Here there are three wheels each having 10 teeth. Every tooth is numbered from 0 to 9. First wheel is called units wheel, second wheel is called Tens and third is called hundreds wheel. First wheel rotates in anti-clock wise direction. When it rotates of a complete rotation, the window shows the next digit. When the first wheel completes one complete rotation the next digit on the 2”’ wheel appears due to mechanical linkage. In his way when tens wheel completes one revolution, the next digit on the hundreds wheel appears. In the same way the thousands and ten-thousands wheel can be added with the mechanical counter.