Tachogenerator
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Transcript of Tachogenerator
WELCOME
TACHOGENERATOR
• Presented by :• 1.asdfadfd• 2.zxcvdsf• Institute :
UPON COMPLETION OF THIS TOPIC WE COME TO KNOW ABOUT :
AC & DC TachogeneratorsPrinciples of TachogeneratorsIts Operation Advantages & Disadvantages
PRINCIPLE
The major principle for tachogenerator is that the relative motion between a Magnetic field & a conductor results the voltage in that conductor.
Tachogenerators are used for measurement of angular velocity • There are mainly two Types
of Tachogenerators :• 1. A.C. Tachogenerator• 2. D.C. Tachogenerator
CONSTRUCTION• An Armature is rotating type &
this magnet is fixed type.• Armature is coupled to a
machine whose velocity is to be measured.
CONSTRUCTION
• It consists of commutator and brushes is connected to armature.
• Output is connected to Moving Coil (MC) type Voltmeter
OPERATION
• When the armature is stationary there is no relative motion between the magnetic field and the armature winding.
• Hence the output voltage is Zero
OPERATION
• 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.
OPERATION
• 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.
ADVANTAGE
• The main advantage of this meter is the direction of rotation is indicated by the polarity of the output voltage
DISADVANTAGE
• The Commutator and Brushes require periodic maintainence
• The output voltage is non - linear
CONSTRUCTION• It consists of :-• Permanent Magnet• Coil (Stator)• Rectfier Bridge• Moving Coil (MC) Voltameter
OPERATION• When the magnet rotates in the
stationary coil an AC voltage is generated• The amplitude and the frequency of this
voltage are both propotional to the speed of rotation.
• Thus either the amplitude or frequency of the induced voltage may be used as a measure of rotational speed
OPERATION
• The output voltage AC Tachogenerator is rectified and is measured with MC meter
ADVANTAGES
• Maintenance free due to absence of brushes and commutators
DISADVANTAGE
• Large number of poles are required• Required high input impendence
display devices
THANK YOU