ELECTRICAL DRIVES,SENSORS ,PLC ,MECHATRONICS SYSTEMS,SPEED SHAFT CONTROL

for the 3rd unit go through this pdf
https://drive.google.com/open?id=0ByqadBQSN1SnVHFiTlZ1QTByRXc&authuser=0

SENSORS ,PLC ,MECHATRONICS SYSTEMS
https://drive.google.com/open?id=0ByqadBQSN1Sndll6S2xHSUlVamc&authuser=0

https://drive.google.com/open?id=0ByqadBQSN1SnOTkyVGdud3FuZHc&authuser=0

SHAFT SPEED CONTROL SYSTEM:

Fig shows a simple automatic control system for the speed of  rotation of a shaft.A potentiometer is used to set the reference value. i.e what voltage is supplied to the differential amplifier as the reference value for the required  speed of rotation. The differential amplifier is used to both compare and amplify the difference between the reference and feedback values, i.e it amplifies the error signal. The amplified error signal is then fed to a motor which in turn adjusts the speed of the rotating shaft.

The speed of the rotating shaft is measured by the tachogenerator , connected to the rotating shaft by means of pair of bevel gears. The signal from the tachogenerator is then fed back to the differential amplifier.

controlled valve -sped of rotation of shaft 

reference value-setting of slider on potentiometer 

comparison element-differential amplifier

error signal-the difference between the output from the potentiometer and that from the tachogenerator system

control unit-the differential amplifier

correction unit-the motor

process-the rotating shaft

measuring device- the tachogenerator