elesrcrc

1. TACHO GENERATOR
R.AMITHESH 18DG06

2. DEFENITION
 Tacho generator is a device which is used for
measuring the speed of shaft and converting into
a voltage so that it can be measured.It converts
angular velocity into voltage.
 They are used to measure the speed of electric
motors, engines, and the equipment they power
:Conveyor belts, machine tools, mixer,fans,etc.

3. PRINCIPLE
 The major principle for tachogenerator is that the
relative motion between a Magnetic field & a
conductor results the voltage in that conductor

4. Types of Tacho generator
 DC Tachogenerator - A DC tachogenerator is a
small DC generator ,which generate electrical
voltage corresponding to the speed of rotating
machine.
 AC Tachogenerator – The AC tachogenerator is a
small brushless alternator with a rotating multi-
pole permanent magnet. The output voltage is
again measured by a voltmeter although the
varying frequency will affect the accuracy of this
instrument.

7. CONSTRUCTION
 An Armature is rotating type & this magnet is
fixed type.
 Armature is coupled to a machine whose velocity
is to be measured.
 It consists of commutator and brushes is
connected to armature.
 Output is connected to Moving Coil (MC) type
Voltmeter

8. WORKING
 When the armature is stationary there is no relative motion between the
magnetic field and the armature winding.
 Hence the output voltage is Zero.
 As the armature speed increases the relative motion also increases.
 The output voltage is induced in the armature winding.
 The magnitude of this voltage is propotional to the speed of armature.
 A commutator and brush are connected in the armature to give the DC
output voltage.
 The polarity of output voltage indicates the direction of rotation.
 This output voltage is measured with the help of moving coil voltmeter
calibrated in terms of speed.

9. THANK YOU