The document outlines the history, principles, types, and applications of tachometers, instruments designed to measure speed. It details various classification methods such as data acquisition (contact vs. non-contact) and measurement techniques (time-based vs. frequency-based), as well as differences between analog and digital tachometers. The document also lists multiple types of tachometers and their specific applications in sectors like automotive, medical, and industrial machinery.

5. History
 The inventor is assumed to be the
German engineer Dietrich Uhlhorn
 He used it for measuring the speed of
machines in 1817
 Since 1840, it has been used to measure
the speed of locomotives

6.  The word comes from Greek ταχος (tachos "speed")
and matron ("measure"). Essentially the words tachometer and
speedometer have identical meaning: a device that measures
speed.
A tachometer is an instrument measuring the rotation speed
of a shaft or disk as in a motor or other machine

7. Working principle of Tachometer

9. Block Diagram
IR SENSOR
ACTIVE
FILTER
Microcon
troller7 Segment Display

10. Types
 Tachometers can be classified on the basis of data
acquisition – contact or non contact types
 They can also be classified on the basis of the
measurement technique – time based or frequency
based technique of measurement
 They can also be classified as analog or digital type

11.  Contact type – The wheel of
the tachometer needs to be
brought into contact with the
rotating object
 Non Contact type – The
measurement can be made
without having to attach the
tachometer to the rotating
object
Classification Based on Data Acquisition Technique

12. Classification Based on Measurement Technique
 Time Measurement – The tachometer calculates speed by
measuring the time interval between the incoming pulses
 Frequency Measurement – The tachometer calculates
speed by measuring the frequency of the incoming pulses

13. Analog Tachometer
• Has a needle and
dial type of interface
• No provision for
storage of readings
• Cannot compute
average, deviation,
etc
Digital Tachometer
• Has a LCD or LED
readout
• Memory is provided
for storage
• Can perform
statistical functions
like averaging, etc
Comparison Between Analog and Digital Tachometers

15. What Are the Different Types of Tachometers?
• Mechanical Tachometers
• Revolution Counter
• Hand Speed Indicator
• Centrifugal Tachometer
• Resonance (vibrating read) Tachometer
• Electrical Tachometers
• Eddy Current or Drag Cup Tachometer
• Contactless Electrical Tachometers
• Magnetic Pickup Tachometer
• Photo-Electric Tachometer

16. Mechanical Tachometers
16

17. Revolution Counter
 Revolution counter is used to measure an average
of rational speed instead of instantaneous
rotational speed.
 It consists of a worm gear that is usually attached
to a spindle. It has two dials, an inner one and an
outer one.
 These are limited to low speed engines and
measure satisfactory up to 2000-3000r.p.m.

18. Hand Speed Indicator
 Hand Speed Indicator has an integral stopwatch and
counter with automatic disconnect.

19. Centrifugal Tachometer
 Centrifugal Tachometer operates on principle that
centrifugal force is proportional to speed of
rotation.
 They are suitable for 4000r.p.m.

20. Resonance (Vibrating Read) Tachometer
 In Vibrating Read Tachometers a series of consecutively
timed steel rods are used to determine speed on basis
of vibrations created by machine.
 These can be used in speed range of 600-10000 rpm .

21. Electrical Tachometers

22. Eddy current or Drag Cup Tachometer
 An Eddy-Current Tachometer uses the interaction of
the magnetic fields generated by a permanent magnet
and a rotor, whose speed of rotation is proportional to
the eddy currents generated.

24. Contactless Electrical Tachometers

25. Magnetic Pickup Tachometer
 A coil wounded on permanent magnet not
on iron core, this configuration enable us to
measure rotational speed of the systems.

26. Photo-Electric Tachometer
 It consists of a opaque disc mounted on the shaft whose speed is
to be measured. The disc has a number of equivalent holes
around the periphery. On one side of the disc there is a source of
light (L) while on the other side there is a light sensor (may be a
photosensitive device or photo-tube) in line with it (light-source).

27. Photo-Electric Tachometer
Computer mouse with a ball

28. General Applications of Tachometer
 Electric tachometers are utilized in machinery and automobiles.
 Tachometers are used in aircraft , rails, automobiles and other
vehicles for indicating the rotation rate of the crankshaft of the
engine.
 Used in traffic engineering to estimate traffic speed and
volume.
 Used for measuring heart rate , arterial blood flow rate ,
respiratory gas flow rate in medical.

29. Industrial Applications of Tachometer
 Mixers
 Conveyors
 Compressors
 Printing Equip
 Fans and Blowers
 Winders
 Motor Control
 PLC Interface
 Extruders
 Molding
 Automated Assembly
 Bottling

32. Thank You