Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Electrification wikipedia , lookup
Commutator (electric) wikipedia , lookup
Electric machine wikipedia , lookup
Voltage optimisation wikipedia , lookup
Brushless DC electric motor wikipedia , lookup
Electric motor wikipedia , lookup
Induction motor wikipedia , lookup
Stepper motor wikipedia , lookup
EXPT.NO.3 TITLE: TO CONTROL SPEED OF D.C.SHUNT MOTOR BY ARMATURE VOLTAGE CONTROL METHOD. APPARATUS: D.C. SHUNT MOTER D.C.AMMETER D.C.VOLTMETER RHEOSTAT RHEOSTAT - 230 VOLT ,12A ,3KW. 0 TO 5/10 Amp. 0 TO 300 V 1000, 1.5 TO 5 Amp. 3000, 1.2 Amp. PRIOR CONCEPTS: WORKING OF D.C.MOTOR AND DIFFERENT TYPES OF D.C.MOTOR. CONNECTION OF D.C.MOTORS SUCH AS D.C.D.C.AMMETER AND D.C.VOLTMETER. HOW TO HANDLE TACHOMETER FOR MEASUREMENT OF SPEED. NEW CONCEPTS: PROPSITION 1: FOR CONTROLLING THE SPEED OF D.C.SHUNT MOTOR STUDENT SHOULD STUDY THE EQUATION FOR SPEED ON D.C.SHUNT MOTOR AND THE PARAMETERS ON WHICH SPEED OF D.C.SHUNT MOTOR DEPENENDS. THE STUDENTS SHOULD KNOW DIFFERENCE TERMS IN THE EQUATION. FOR SPEED OF D.C.SHUNT MOTOR N=(V –Ia.Ra)/ I WHERE , I=SPEED OF MOTOR. V=APPLIED VOLTAGE. Ia=ARMATURE CURRENT. I=FIELD FLUX. CONCEPT STRUCTURE 1 :SPEED OF D.C.SHUNT MOTOR CAN BE CONTROOLED BY BY VARYING FLUX PRODUCED IN THE FIELD OF MOTOR CHANGING THE APPLIED VOLTAGE NOT PRACTICABLE METHOD BY VARYING THE `V`ACROSS ARMATURE OF THE MOTOR ONLY SPEEDS ABOVE NORMAL CAN BE OBTAINED ONLY SPEEDS BELOW NORMAL CAN BE ORTAINED LEARNING OBJECTIVES:INTELLECTUAL SKILLS: TO UNDERSTAND CONNECTION OF THE OF D.C.SHUNT MOTOR WITH 3 POINT STARTER. TO CONTROL THE SPEED OF D.C.SHUNT MOTOR BY VARYING ARMATURE CIRCUIT RESISTANCE. MOTOR SKILLS: ABILITY TO CONNECT 3 POINT STARTER TO START MOTOR. ABILITY TO VARY ARMATURE CIRCUIT RESISTANCE AND MEASURE VARIABLE SPEED AND RECORD THE OBSERVATIONS. INSTRUMENT: SR.NO. INSTRUMENT 1. D.C.MOTOR 2. VOLTMETER 3. AMMETER NAME OF MANUFACTURER SERIAL NO.OF THE INSTRUMENT STEPWISE PROCEDURE: CONNECT THE MOTOR WITH ALL METERS AND RHEOSTAT AS PER THEIR POLARITIES SHOWN IN FIG. KEEP BOTH THE REHEOSTAT IN THEIR INITIAL POSITIONS. SWITCH ON THE D.C.SUPPLY BY MAKING ICDP SWITCHES GRADUALLY ROTATE THE HANDLE OF 3 POINT STARTER IN CLOCKWISE DIRECTION TO START THE MOTOR. ADJUST THE SPEED OF D.C.SHUNT MOTOR TO IT`S RATED SPEED BY VARYING THE FIELD CIRCUIT RESISTANCE. NOTE DOWN THE INITIAL VOLTAGE ACROSSS THE ARMATURE TERMINALS AND ALSO SPEED OF THE ROTOR. START VARYING ARMATURE CIRCUIT RESISTANCE AND NOTE DOWN CORRESPONDING SPEED. PLOT THE GRAPH OF ARMATURE VOLTAGE ON X-AXIS AND SPEED ON Y-AXIS. OBSERVATIONS: TABLE FOR DIFFERENT READINGS SR.NO. VOLTAGE ACROSS ARMATURE SPEED OF MOTOR IN RPM CONCLUSION: AS VOLTAGE ACROSS OF THE ARMATURE AS THE MOTOR DECREASES SPEED OF THE MOTOR DECREASES. THUS WE CAN OBTAIN SPEEDS BELOW NORMAL SPEED THE MOTOR .THEREFORE THIS METHOD CAN BE ALSO KNOWN AS SPEED CONTOL OF D.C.SHUNT MOTOR BELOW NORMAL SPEED. TABLE FOR DIFFERENT READINGS SR.NO. FIELD CURRENT If IN Amp. SPEED OF MOTOR IN RPM CONCLUSION: AS THE FIELD CIRCUIT STARTS DECREASING MOTOR SPEED INCREASES. THUS WE CAN OBTAIN SPEEDS ABOVE NORMAL SPEED THE MOTOR .THEREFORE THIS METHOD CAN BE ALSO KNOWN AS SPEED CONTOL OF D.C.SHUNT MOTOR BELOW NORMAL SPEED QUESTIONS: Q1.STATE ANY TWO USES OD D.C.SHUNT MOTOR? Q2.STATE FLEMING LEFT HAND RULE? Q3.WHAT ARE DIFFERENT WINDINGS OF D.C.SHUNT MOTORS. Q4. HOW SPEED OF D.C.SHUNT MOTOR CHANGES WITH FLUX ? Q5.HOW THE NORMAL SPEED OF THE MOTOR CAN BE BEFORE VARYING THE FLUX? CIRCUIT DIAGRAM