WHAT IS A TRANSFORMER?
TRANSFORMER IS A STATIC DEVICE WHICH TRANSFERS AN ELECTRICAL POWER FROM ONE ELECTRICAL CIRCUIT TO ANOTHER ELECTRICAL CIRCUIT OR MULTIPLE CIRCUITS. IT IS A STATIC OR STATIONARY DEVICE BECAUSE IT DOES NOT CONTAIN ANY MOVING PART LIKE ELECTRICAL MOTORS.

PRINCIPLE OF TRANSFORMER -

TRANSFORMER IS A DEVICE WHICH IS CAPABLE OF CONVERTING AC VOLTAGES AND CURRENT OF HIGH VALUE INTO LOW OR DESIRED VALUE AND TRANSFERS IT TO THE REQUIRED LOCATION FOR UTILIZATION PURPOSE. ELECTRICAL TRANSFORMER PLAYS AN IMPORTANT ROLE IN ELECTRICAL POWER SYSTEM.

TRANSFORMER WORKS ON THE PRINCIPLE OF MUTUAL INDUCTION. IN TRANSFORMER THERE ARE TWO COILS PLACED USING SAME CORE BUT ON DIFFERENT LIMBS, ONE IS PRIMARY COIL AND OTHER IS SECONDARY COIL. THIS CREATES A MAGNETIC CIRCUIT FOR BOTH COILS. THESE COILS ARE HAVING HIGH MUTUAL INDUCTANCE, WHEN AN ELECTRICAL CURRENT PASSES THROUGH THE PRIMARY COIL IT PRODUCES MAGNETIC FIELD AROUND IT, WHICH WILL PASS THROUGH THE TRANSFORMER CORE AND LINKS WITH THE SECONDARY COIL. THE MAGNETIC FIELD OR FLUX IS ALTERNATING IN NATURE THUS, ACCORDING TH FARADAY'S LAW OF ELECTROMAGNETIC INDUCTION AN EMF (ELECTROMOTIVE FORCE) WILL BE INDUCED IN THE SECONDARY COIL AND CURRENT WILL START FLOWING THROUGH IF LOAD IS CONNECTED. THIS PHENOMENA IS CALLED MUTUAL INDUCTION.

SINGLE PHASE TRANSFORMER

THE TRANSFORMER INCREASES OR DECREASES THE VOLTAGE LEVEL DEPENDS ON THE RELATIVE NUMBER OF TURNS BETWEEN THE PRIMARY AND SECONDARY SIDE OF THE TRANSFORMER.

A TRANSFORMER THAT INCREASES VOLTAGE BETWEEN THE PRIMARY TO SECONDARY WINDINGS IS CALLED AS A STEP-UP TRANSFORMER. FOR STEP UP TRANSFORMER THE NUMBER OF TURNS ON PRIMARY COIL IS LESS THAN SECONDARY COIL THUS THE VOLTAGE WILL INCREASE.

A TRANSFORMER THAT DECREASES VOLTAGE BETWEEN THE PRIMARY TO SECONDARY WINDINGS IS CALLED AS A STEP-DOWN TRANSFORMER. FOR STEP DOWN TRANSFORMER THE NUMBER OF TURNS ON PRIMARY COIL IS MORE THAN SECONDARY COIL THUS THE VOLTAGE WILL DECREASE.

[NOTE = THERE IS A DIFFERENCE BETWEEN INDUCTION AND PRODUCTION. WE ARE INDUCING AN EMF FROM MAGNETIC FIELD LINES THUS WE CALL IT AS "INDUCTION OF EMF IN SECONDARY WINDING". IT IS NOT THE MAGNETIC LINES THAT SUPPOSED TO PRODUCE EMF, WE ARRANGED THE CIRCUITRY IN SUCH A WAY THAT MAGNETIC LINES ARE SET IN THE CORE AND WILL BE LINKED WITH SECONDARY WINDING TO INDUCE EMF IN IT.]

MAJOR PARTS OF TRANSFORMER –

1. TRANSFORMER WINDINGS – THERE ARE TWO WINDINGS IN TRANSFORMER PRIMARY AND SECONDARY. PRIMARY WINDING IS THE ONE WHICH CARRIES THE CURRENT FROM SOURCE AND SECONDARY WINDING IS THE ONE WHO TRANSFERS THE CURRENT TO LOAD. WINDINGS ARE MADE UP OF COPPER WHICH HAS HIGH CONDUCTIVITY AND HIGH DUCTILITY PROPERTY. WINDINGS ARE INSULATED WITH VARNISH.
2. MAGNETIC CORE – CORE IS MAJOR PART IN TRANSFORMER IT DOES MULTIPLE JOBS OF HOLDING OR SUPPORTING THE TRANSFORMER WINDINGS AND PROVIDING LOW RELUCTANCE PATH TO THE MAGNETIC FLUX LINES. CORE IS MADE UP OF LAMINATED SILICON STEEL STAMPING TO PROVIDE HIGH PERMEABILITY AND REDUCE THE CORE/IRON LOSSES IN TRANSFORMER.
3. INSULATION FOR CORE AND WINDINGS – INSULATION IS IMPORTANT FOR WINDINGS TO PREVENT THEM FROM CAUSING SHORT CIRCUIT. INSULATION IS ALSO IMPORTANT AT TERMINALS TO PREVENT THEM FROM CORROSION AND ANY DIRECT CONTACT WITH EACH OTHER. FOR SMALL TRANSFORMER INSULATION PAPER, INSULATION TAPE, VARNISH, LAMINATION, INSULATION OIL IS MOSTLY USED AS INSULATION MEDIA.

VOLTAGE TRANSFORMER RATIO –

                (E1/N1) = (E2/N2) = K

WHERE,     K IS VOLTAGE TRANSFORMER RATIO AND IT IS CONSTANT,

           E1 IS PRIMARY VOLTAGE,

           E2 IS SECONDARY VOLTAGE,

           N1 IS NO. OF PRIMARY WINDING TURNS,

           N2 IS NO. OF SECONDARY WINDING TURNS.

IF,        N2 > N1, THEN K > 1 FOR STEP-UP TRANSFORMER,

IF,        N2 < N1, THEN K < 1 FOR STEP-DOWN TRANSFORMER.

WHAT IS AN ELECTRIC MOTOR?
ELECTRIC MOTOR IS A MACHINE THAT CONVERTS ELECTRICAL ENERGY INTO  MECHANICAL ENERGY. ELECTRICAL ENERGY IS SUPPLIED BY DC POWER FOR DC MOTORS AND WITH AC POWER FOR AC MOTORS.

PRINCIPLE OF ELECTRIC MOTOR -

WE NEED TO GIVE DOUBLE EXCITATION TO MAKE A DC MOTOR TO ROTATE. IN THE DC MOTOR, WE GIVE ONE SUPPLY TO THE STATOR AND ANOTHER TO THE ROTOR THROUGH BRUSH ARRANGEMENT. BUT IN INDUCTION MOTOR, WE GIVE ONLY ONE SUPPLY. IT IS SIMPLE, FROM THE NAME ITSELF WE CAN UNDERSTAND THAT HERE, THE INDUCTION PROCESS IS INVOLVED. WHEN WE GIVE THE SUPPLY TO THE STATOR WINDING, A MAGNETIC FLUX GETS PRODUCED IN THE STATOR DUE TO THE FLOW OF CURRENT IN THE COIL. THE ROTOR WINDING IS SO ARRANGED THAT EACH COIL BECOMES SHORT-CIRCUITED THUS IS FORMS THE CLOSED CIRCUIT .

THE FLUX FROM THE STATOR CUTS THE SHORT-CIRCUITED COIL IN THE ROTOR. AS THE ROTOR COILS ARE SHORT-CIRCUITED, ACCORDING TO FARADAY’S LAW OF ELECTROMAGNETIC INDUCTION, THE CURRENT WILL START FLOWING THROUGH THE COIL OF THE ROTOR. WHEN THE CURRENT THROUGH THE ROTOR COILS FLOWS, ANOTHER FLUX GETS GENERATED IN THE ROTOR. NOW THERE ARE TWO FLUXES, ONE IS STATOR FLUX, AND ANOTHER IS ROTOR FLUX. THE ROTOR FLUX WILL BE LAGGING IN RESPECT OF THE STATOR FLUX. BECAUSE OF THAT, THE ROTOR WILL EXPERIENCE A TORQUE WHICH WILL MAKE THE ROTOR TO ROTATE IN THE DIRECTION OF THE ROTATING MAGNETIC FIELD. THIS IS THE WORKING PRINCIPLE OF BOTH SINGLE AND THREE PHASE INDUCTION MOTORS.

THE DIRECTIONS OF THIS INDUCED EMF, CURRENT FLOW AND ROTATIONAL TORQUE CAN BE DETERMINED WITH THE HELP OF FLEMING'S LEFT HAND RULE.FLEMING'S LEFT HAND RULE, SHOWS THE DIRECTION OF CURRENT, FORCE/TORQUE &  MAGNETIC FIELD. THIS RULE ONLY SHOWS THE DIRECTION OF EITHER ONE IF OTHER TWO DIRECTIONS ARE KNOWN. HOWEVER, IT DOES NOT SPECIFIES THE MAGNITUDE OF THESE PARAMETERS.

FLEMING'S LEFT HAND RULE DIRECTIONS

TO APPLY FLEMING'S LEFT HAND RULE WE WILL USE 3 FINGERS OF LEFT HAND AND HELD THEM PERPENDICULAR TO EACH OTHER SUCH THAT, THE THUMB WILL SHOW DIRECTION OF FORCE/MOTION OF CONDUCTOR, FOREFINGER WILL SHOW THE DIRECTION OF MAGNETIC FIELD, MIDDLE FINGER WILL SHOW DIRECTION OF CURRENT.THIS RULE IS APPLICABLE FOR ELECTRIC MOTORS.

UNDERSTANDING WORKING OF ELECTRICAL MOTOR -

AS MENTIONED ABOVE DC MOTOR CAN BE STARTED AND RUN WITH THE USE OF DOUBLE EXCITATION. HOWEVER IN CASE OF AC MOTOR WE ONLY GIVE ONE SUPPLY TO STATOR WINDINGS ONLY BUT THIS IS NOT ENOUGH FOR ROTATING THE SINGLE PHASE AC MOTOR. AS WE KNOW, IN ORDER TO FOR ROTOR TO ROTATE WE NEED ROTATIONAL TORQUE BUT IN SINGLE PHASE AC MOTORS ACCORDING TO THE NATURE OF SUPPLY THE POLARITIES ARE KEEP ON CHANGING AND THUS IT CAUSES TO PRODUCE OPPOSITE TORQUE TO PRODUCE IN ROTOR WHICH WILL STOP THE ROTATION. THUS, IN ORDER TO ROTATE WE NEED TO PROVIDE THE SUPPLY TO SINGLE PHASE AC MOTOR IN SUCH A WAY THAT IT WILL PROVIDE A ROTATIONAL TORQUE IN UNI-DIRECTION THUS MOTOR WILL ROTATE IN THE SAME DIRECTION AS TORQUE AND WILL NOT STOP UNTIL THE INTERRUPTION OF SUPPLY.

WORKING OF DC MOTOR - 

WORKING PRINCIPLE OF DC MOTOR MAINLY DEPENDS UPON FLEMING LEFT HAND RULE. IN A BASIC DC MOTOR, AN ARMATURE IS PLACED IN BETWEEN MAGNETIC POLES. IF THE ARMATURE WINDING IS SUPPLIED BY AN EXTERNAL DC SOURCE, CURRENT STARTS FLOWING THROUGH THE ARMATURE CONDUCTORS. AS THE CONDUCTORS ARE CARRYING CURRENT INSIDE A MAGNETIC FIELD, THEY WILL EXPERIENCE A FORCE WHICH TENDS TO ROTATE THE ARMATURE. SUPPOSE ARMATURE CONDUCTORS UNDER N POLES OF THE FIELD MAGNET, ARE CARRYING CURRENT DOWNWARDS AND THOSE UNDER S POLES ARE CARRYING CURRENT UPWARDS. BY APPLYING FLEMING’S LEFT HAND RULE, THE DIRECTION OF FORCE F, EXPERIENCED BY THE CONDUCTOR UNDER N POLES AND THE FORCE EXPERIENCED BY THE CONDUCTORS UNDER S-POLES CAN BE DETERMINED. IT IS FOUND THAT AT ANY INSTANT THE FORCES EXPERIENCED BY THE CONDUCTORS ARE IN SUCH A DIRECTION THAT THEY TEND TO ROTATE THE ARMATURE.

(MINIMUM TORQUE)
NO CURRENT WILL FLOW THROUGH CONDUCTORS

AGAIN, DUE THIS ROTATION THE CONDUCTORS UNDER N-POLES COME UNDER S-POLE AND THE CONDUCTORS UNDER S-POLES COME UNDER N-POLE. WHILE THE CONDUCTORS GO FORM N-POLES TO S-POLE AND S-POLES TO N-POLE, THE DIRECTION OF CURRENT THROUGH THEM, IS REVERSED BY MEANS OF COMMUTATOR. DUE TO THIS REVERSAL OF CURRENT, ALL THE CONDUCTORS COME UNDER N-POLES CARRY CURRENT IN DOWNWARD DIRECTION AND ALL THE CONDUCTORS COME UNDER S-POLES CARRY CURRENT IN UPWARD DIRECTION AS SHOWN IN THE FIGURE. HENCE, EVERY CONDUCTOR COMES UNDER N-POLE EXPERIENCES FORCE IN SAME DIRECTION AND SAME IS TRUE FOR THE CONDUCTORS COME UNDER S-POLES. THIS PHENOMENON HELPS TO DEVELOP CONTINUOUS AND UNIDIRECTIONAL TORQUE.

(MAXIMUM TORQUE)
MAXIMUM CURRENT WILL FLOW THROUGH THE CONDUCTORS

WORKING OF AC MOTOR -

WORKING OF ELECTRIC MOTOR IN THE CASE OF INDUCTION MOTOR IS LITTLE BIT DIFFERENT FROM DC MOTOR. IN SINGLE PHASE INDUCTION MOTOR, WHEN A SINGLE PHASE SUPPLY IS GIVEN TO THE STATOR WINDING, A PULSATING MAGNETIC FIELD IS PRODUCED AND IN A THREE PHASE INDUCTION MOTOR, WHEN THREE PHASE SUPPLY IS GIVEN TO THREE PHASE STATOR WINDING, A ROTATING MAGNETIC FIELD IS PRODUCED. THE ROTOR OF AN INDUCTION MOTOR IS EITHER WOUND TYPE OR SQUIRREL CADGE TYPE. WHATEVER MAY BE THE TYPE OF ROTOR, THE CONDUCTORS ON IT ARE SHORTED AT END TO FORM CLOSED LOOP. DUE TO ROTATING MAGNETIC FIELD, THE FLUX PASSES THROUGH THE AIR GAP BETWEEN ROTOR AND STATOR, SWEEPS PAST THE ROTOR SURFACE AND SO CUTS THE ROTOR CONDUCTOR. HENCE ACCORDING TO FARADAY’S LAW OF ELECTROMAGNETIC INDUCTION, THERE WOULD BE A INDUCED CURRENT CIRCULATING IN THE CLOSED ROTOR CONDUCTORS. THE AMOUNT OF INDUCED CURRENT IS PROPORTIONAL TO THE RATE OF CHANGE OF FLUX LINKAGE WITH RESPECT TO TIME. AGAIN THIS RATE OF CHANGE OF FLUX LINKAGE IS PROPORTIONAL TO THE RELATIVE SPEED BETWEEN ROTOR AND ROTATING MAGNETIC FIELD. AS PER LENZ'S LAW THE ROTOR WILL TRY TO REDUCE THE EVERY CAUSE OF PRODUCING CURRENT IN IT. HENCE THE ROTOR ROTATES AND TRIES TO ACHIEVE THE SPEED OF ROTATING MAGNETIC FIELD TO REDUCE THE RELATIVE SPEED BETWEEN ROTOR AND ROTATING MAGNETIC FIELD.

ARE SINGLE PHASE AC MOTORS SELF STARTING?

THE ANSWER IS "NO";

WE KNOW THAT THE AC SUPPLY IS A SINUSOIDAL WAVE AND IT PRODUCES A PULSATING MAGNETIC FIELD IN THE UNIFORMLY DISTRIBUTED STATOR WINDING.

SINCE WE CAN ASSUME THE PULSATING MAGNETIC FIELD AS TWO OPPOSITELY ROTATING MAGNETIC FIELDS, THERE WILL BE NO RESULTANT TORQUE PRODUCED AT THE STARTING, AND HENCE THE MOTOR DOES NOT RUN. AFTER GIVING THE SUPPLY, IF THE ROTOR IS MADE TO ROTATE IN EITHER DIRECTION BY AN EXTERNAL FORCE, THEN THE MOTOR WILL START TO RUN. WE CAN SOLVE THIS PROBLEM BY MAKING THE STATOR WINDING INTO TWO WINDING – ONE IS THE MAIN WINDING, AND ANOTHER IS AUXILIARY WINDING.

WE CONNECT ONE CAPACITOR IN SERIES WITH THE AUXILIARY WINDING. THE CAPACITOR WILL MAKE A PHASE DIFFERENCE WHEN CURRENT FLOWS THROUGH BOTH COILS. WHEN THERE IS A PHASE DIFFERENCE, THE ROTOR WILL GENERATE A STARTING TORQUE, AND IT WILL START TO ROTATE. PRACTICALLY WE CAN SEE THAT THE FAN DOES NOT ROTATE WHEN THE CAPACITOR GETS DISCONNECTED FROM THE MOTOR, BUT IF WE ROTATE WITH THE HAND, IT WILL START ROTATING. THAT IS WHY WE USE A CAPACITOR IN THE SINGLE-PHASE INDUCTION MOTOR.

SINGLE PHASE AC INDUCTION MOTOR CIRCUIT

ARE THREE PHASE AC MOTORS SELF STARTING?

THE ANSWER IS "YES";

UNLIKE SINGLE PHASE, IN A THREE PHASE SYSTEM, THERE ARE THREE SINGLE PHASE LINES WITH A 120° PHASE DIFFERENCE. SO THE ROTATING MAGNETIC FIELD HAS THE SAME PHASE DIFFERENCE WHICH WILL MAKE THE ROTOR TO MOVE. IF WE CONSIDER THREE PHASES A, B, AND C WHEN PHASE A GETS MAGNETIZED, THE ROTOR WILL MOVE TOWARDS THE PHASE A WINDING A, IN THE NEXT MOMENT PHASE B WILL GET MAGNETIZED AND IT WILL ATTRACT THE ROTOR AND THEN PHASE C. SO THE ROTOR WILL CONTINUE TO ROTATE.

WORKING OF SYNCHRONOUS MOTOR - 

IN SYNCHRONOUS MOTOR, WHEN BALANCED THREE PHASE SUPPLY IS GIVEN TO THE STATIONARY THREE PHASE STATOR WINDING, A ROTATING MAGNETIC FIELD IS PRODUCED WHICH ROTATES AT SYNCHRONOUS SPEED. NOW IF AN ELECTROMAGNET IS PLACED INSIDE THIS ROTATING MAGNETIC FIELD, IT IS MAGNETICALLY LOCKED WITH THE ROTATING MAGNETIC FIELD AND THE ROTOR ROTATES WITH THE ROTATING MAGNETIC FIELD AT SAME SPEED THAT IS AT SYNCHRONOUS SPEED.

WHAT IS AN ALTERNATOR?
ALTERNATOR IS AN ELECTRIC MACHINE THAT CONVERTS MECHANICAL ENERGY INTO ELECTRICAL ENERGY. THE MECHANICAL ENERGY CAN BE PROVIDED BY MEANS OF PRIME MOVERS.

PRINCIPLE OF ALTERNATOR?

ALTERNATOR WORKS ON THE PRINCIPLE OF FARADAY'S LAW OF ELECTROMAGNETIC INDUCTION, "WHENEVER A CONDUCTOR IS ROTATED BETWEEN A MAGNETIC FIELD, THE CURRENT GETS INDUCED IN THAT CONDUCTOR DUE TO RELATIVE MOTION BETWEEN CONDUCTOR AND MAGNETIC FIELD".

THERE IS ANOTHER RULE IMPLEMENTED FOR ALTERNATORS/GENERATORS WHICH FLEMING'S RIGHT HAND RULE, THIS RULE SHOWS THE DIRECTION OF CURRENT, FORCE, MAGNETIC FIELD. THIS RULE ONLY SHOWS THE DIRECTION OF EITHER ONE IF OTHER TWO DIRECTIONS ARE KNOWN. HOWEVER, IT DOES NOT SPECIFIES THE MAGNITUDE OF THESE PARAMETERS.

TO APPLY FLEMING'S RIGHT HAND RULE WE WILL USE 3 FINGERS OF RIGHT HAND AND HELD THEM PERPENDICULAR TO EACH OTHER SUCH THAT, THE THUMB WILL SHOW DIRECTION OF FORCE/MOTION OF CONDUCTOR, FOREFINGER WILL SHOW THE DIRECTION OF MAGNETIC FIELD, MIDDLE FINGER WILL SHOW DIRECTION OF CURRENT.

UNDERSTANDING WORKING OF ALTERNATOR -

LET US TAKE TWO OPPOSITE MAGNETIC POLES N-POLE AND S-POLE. WE WILL PLACE A COIL/CONDUCTOR IN BETWEEN THE TWO MAGNETIC POLES. WE WILL DIVIDE THE COIL/CONDUCTOR IN TWO PARTS, CONDUCTOR A-B AND THE CONDUCTOR C-D. THE MAGNETIC FIELD OR LINES IS MOVING FROM N-POLE TO S-POLE.

NEGLIGIBLE CURRENT FLOW 0°

NOW, AS PER THE PRINCIPLE, CONDUCTOR NEEDS TO BE ROTATED IN THE MAGNETIC FIELD. FOR THE FIRST ROTATION CONDUCTOR A-B WILL ROTATED CLOCKWISE FOR 90°.NOW THE CONDUCTOR A-B WILL MOVE NEAR S-POLE AND CONDUCTOR C-D WILL MOVE NEAR N-POLE IN HORIZONTAL POSITION.

NOW IF WE APPLY FLEMING'S RIGHT HAND RULE RULE WE CAN SEE THAT THE CONDUCTOR IS NOW PERPENDICULAR TO THE MAGNETIC FILED. THUS, IT WILL PROVIDE MAXIMUM INDUCED CURRENT BECAUSE CONDUCTOR WILL CUT MORE AMOUNT OF MAGNETIC FIELD.AS WE KNOW THE DIRECTIONS OF MOTION OF CONDUCTOR AND THE MAGNETIC FIELD WE CAN USE THE FLEMING'S RIGHT HAND RULE AND CHECK THE DIRECTION OF CURRENT, WE CAN SAY THAT THE CURRENT IS NOW MOVING THROUGH CONDUCTOR A-B FROM POINT A TO B. AND SIMILARLY, THE CONDUCTOR C-D WILL HAVE CURRENT FLOWING FROM POINT C TO D.

MAXIMUM CURRENT FLOW 90°

SO, FOR THE NEXT 90° ROTATION THE CONDUCTORS A-B AND C-D ARE NOW COME IN VERTICAL POSITION. AT THIS POSITION THE CONDUCTOR WILL CUT NEGLIGIBLE AMOUNT OF FLUX AND ALMOST ZERO CURRENT WILL BE INDUCED IN THE CONDUCTOR.

NEGLIGIBLE CURRENT FLOW 180°

ONCE AGAIN, FOR NEXT 90° OF ROTATION THE CONDUCTOR A-B IS NOW COME IN THE VICINITY OF N-POLE AND CONDUCTOR C-D WILL MOVE NEAR S-POLE HOWEVER, THE DIRECT OF CURRENT THROUGH THE CONDUCTOR A-B IS NOW FROM POINT B TO A, AND FOR CONDUCTOR C-D THE DIRECTION OF CURRENT FROM POINT D TO C.

MAXIMUM CURRENT FLOW 270°

THUS, AS PER THE ROTATION THE CONDUCTOR WILL KEEP ON ROTATING AND CURRENT DIRECTION WILL BE KEEP ON CHANGING ACCORDINGLY. THE CIRCULATING CURRENT WHEN THE CONDUCTOR COMES IS HORIZONTAL POSITION FROM VERTICAL POSITION IS B->A->D->C.

FROM THIS WE CAN SAY THAT THE CURRENT WHICH IS INDUCED AT EVERY 180° OF ROTATION WILL FLOW IN OPPOSITE DIRECTION WHICH RESULT IN TOTAL 360° OF ROTATION TO GIVE 1 COMPLETE CYCLE OF AC WAVEFORM OF CURRENT.HOWEVER, ALTERNATOR PRODUCED 3 PHASE OUTPUT IN A MORE SIMILAR BUT LESS DIFFERENT WAY WHICH WE WILL DISCUSS NOW.

HOW 3-PHASE AC POWER IS PRODUCED BY ALTERNATOR?

NOW AS WE KNOW HOW THE ALTERNATOR INDUCES CURRENT IN IT, LET US KNOW HOW TO UTILIZE THIS CURRENT. SO, IF WE TAKE THIS INDUCED CURRENT OUT WITH THE HELP OF BRUSHES WE CAN UTILIZE THIS AC CURRENT.

HOWEVER, THE PRACTICAL ALTERNATOR HAS A DIFFERENT DESIGN THAN A TRADITION GENERATOR DESIGN. THE ACTUAL ALTERNATOR HAS STATIONARY ARMATURE AND ROTATING FIELD INSTEAD OF TRADITION GENERATOR DESIGN. IN ALTERNATOR ROTOR IS CONNECTED WITH TURBINE BLADES WHICH IS ROTATED WITH THE HELP OF SOME MECHANICAL FORCE. THIS WILL HELP ROTOR TO ROTATE AT SYNCHRONOUS SPEED Ns. THE ARMATURE CONDUCTORS ARE STATIONARY AND THEY ARE DISPLACED AT 120° ARRANGEMENT IN THE SLOTS. THIS WILL CAUSE THE CONDUCTORS TO CUT THE MAGNETIC FILED EVERY 120° OF TIME DELAY. RESULTING IN THE PRODUCTION OF THREE DIFFERENT PHASES INSTEAD OF ONLY SINGLE PHASE OF 360° OF AC CYCLE. THIS PRODUCED 3 PHASE AC POWER CAN NOW BE TRANSMITTED TO DISTRIBUTION STATION TO FULFILL THE DOMESTIC AND INDUSTRIAL CONSUMER NEEDS.

3-PHASE AC WAVEFORM

WHAT IS AN ELECTRICAL MACHINE?

AN ELECTRICAL MACHINE IS A DEVICE THAT CONVERTS MECHANICAL ENERGY INTO ELECTRICAL ENERGY AND VICE VERSA. FOR EX. GENERATOR AND MOTOR. HOWEVER, TRANSFORMER IS A TYPE OF MACHINE THAT DOES NOT CONVERT ONE FORM OF ENERGY INTO OTHER BUT IT DOES CONVERTS ONE AC VOLTAGE LEVEL INTO ANOTHER AC VOLTAGE LEVEL.
AN ELECTRICAL MACHINES PLAYS VITAL ROLE IN NOT ONLY INDUSTRIES BUT ALSO IN OUR DAILY LIFE. ELECTRICAL MACHINES ARE USED IN FAN, AC, HAIR DRYER, VEHICLES, TOYS, ETC WHICH WE USE IN DAILY WITHOUT THEM OUR LIFE MORE LIKELY TO BE STOPPED.

TYPES OF ELECTRICAL MACHINES:

ELECTRIC GENERATOR - 

AN ELECTRIC GENERATOR IS A MACHINE THAT CONVERTS MECHANICAL ENERGY INTO ELECTRICAL ENERGY. IT WORKS ON THE PRINCIPLE OF ELECTROMAGNETIC INDUCTION. THIS STATES THAT WHENEVER A ROTATING CONDUCTOR PLACED IN A MAGNETIC FIELD IT CUTS THE MAGNETIC FIELD WHICH INDUCED EMF(ELECTROMOTIVE FORCE) IN THE CONDUCTOR.

EMF (ELECTROMOTIVE FORCE) IS NOTHING BUT A VOLTAGE OR ELECTRIC POTENTIAL. THAT CAUSES CURRENT TO FLOW THROUGH A CONDUCTOR.

GENERATOR IS MADE UP OF A ROTOR AND A STATOR. MECHANICAL ENERGY IN THE FORM OF ROTATION IS PROVIDED TO THE ROTOR BY MEANS OF PRIME MOVERS SUCH AS, TURBINES LIKE, STEAM TURBINE, WIND TURBINE, WATER TURBINE, ETC. ALSO BY IC ENGINES, ETC.

TYPES OF ELECTRICAL GENERATOR -

• AC GENERATOR OR ALTERNATOR = THIS GENERATORS CONVERTS MECHANICAL ENERGY INTO AC CURRENT. ALTERNATORS HAVE STATIONARY ROTOR AND ROTATING FIELD OR STATOR.

• SALIENT POLE TYPE - THIS ALTERNATOR USED FOR LOW AND MEDIUM SPEED BECAUSE IT HAS LARGE NUMBER OF POLES PROJECTING OUT OF ITS PERIPHERY. THIS ALTERNATORS HAVE LARGE DIAMETER AND SHORT AXIAL LENGTH.

• NON-SALIENT OR CYLINDRICAL TYPE - THIS ALTERNATOR HAS SHORT DIAMETER AND LARGE AXIAL LENGTH OF ROTOR, WHERE THE FILED WINDING IS PLACED INSIDE THE TOOTHED TYPE SLOTS PRESENT ON ITS OUTER PERIPHERY. THUS IT CAN BE USED AT HIGH SPEED. IT HAS ONLY 2 OR 4 NUMBER OF POLES.

•  DC GENERATOR = THIS GENERATOR CONVERTS MECHANICAL ENERGY INTO DC CURRENT. DC GENERATORS HAVE ROTATING ROTOR AND STATIONARY FIELD.

• SELF EXCITED DC GENERATOR - IN THIS TYPE FIELD COIL IS CONNECTED WITH ARMATURE IN EITHER SERIES OR PARALLEL OR SERIES-PARALLEL COMBINATION. 

• SERIES GENERATOR - FIELD WINDING IS CONNECTED IN SERIES WITH ARMATURE WINDING.

• SHUNT GENERATOR - FIELD WINDING IS CONNECTED IN PARALLEL WITH ARMATURE WINDING.

• COMPOUND GENERATOR - FIELD COILS ARE CONNECTED IN SERIES AND PARALLEL WITH THE ARMATURE WINDING.

• SHORT SHUNT GENERATOR.

• LONG SHUNT GENERATOR.

• SEPARATELY EXCITED GENERATOR  - IN THIS TYPED OF GENERATOR THE FIELD WINDING DOES NOT COME IN CONTACT WITH ARMATURE WINDING PHYSICALLY, THE SOURCE IS SEPARATELY PROVIDED TO FIELD WINDING.

UNDERSTANDING BASICS OF ELECTRICITY:

THE GREATEST INVENTION OF MANKIND IS AN ELECTRICITY. THERE IS NO FUTURE FOR HUMANITY WITHOUT AN ELECTRICITY. MOST OF THE EQUIPMENTS IN DAY TO DAY LIFE REQUIRES AN ELECTRICITY AT SOME POINT IN ORDER TO RUN. MACHINES ARE THE MOST IMPORTANT PART OF HUMAN LIFE AS THEY HELP SAVING HUGE AMOUNT OF HUMAN EFFORTS AND TIME.

AN ELECTRICITY CAN BE CREATED PHYSICALLY (FOR EX. FRICTION OF CARPET AND SOCKS) AND/OR CHEMICALLY (LIKE IN BATTERIES) IN THE FORM OF CHARGE. NOW, ELECTRICITY CAN BE EXPRESSED SIMPLY AS MOVEMENT OF CHARGE FROM, POSITIVE POINT TO A NEGATIVE POINT. NO MATTER HOW THE ELECTRICITY IS CREATED THE MOVEMENT OF DISCHARGE IS CALLED ELECTRICITY.

UNDERSTANDING CURRENT:

THE RATE/MEASURE OF FLOW OF ELECTRICAL CHARGE IS CALLED AS "ELECTRICAL CURRENT". THE UNIT OF CURRENT IS "AMPERES". THERE ARE TWO TYPES OF ELECTRICAL CURRENT, ALTERNATING CURRENT(AC) AND DIRECT CURRENT(DC).
DIRECT CURRENT(DC) - DC IS THE CONSTANT CURRENT THAT FLOWS IN THE SAME DIRECTION TILL THE VOLTAGE POLARITIES ARE CONSTANT. IN ORDER TO CHANGE THE DIRECTION OF FLOW OF DC CURRENT WE NEED TO CHANGE THE VOLTAGE POLARITIES OF THE CIRCUIT.

DC SUPPLY

ALTERNATING CURRENT(AC) - AC IS THE CURRENT THAT HAS A NATURAL ZERO PERIOD. THAT IS, IT CHANGES ITS DIRECTION ALONG WITH VOLTAGE POLARITIES AT A CERTAIN PERIOD. THIS PERIOD IS DEPEND UPON THE FREQUENCY.

AC SUPPLY

SCIENTIST SUCH AS, THOMAS EDISON AND A. VOLTA HAS CREATED THE THEORY OF DIRECT CURRENT WHILE NICOLA TESLA HAS INVENTED AN AC CURRENT THEORY. THE DC IS MOSTLY USED AT PORTABLE APPLICATIONS AS THE TRANSMISSION OF DC IS TOO INEFFICIENT.

HOWEVER THE AC CURRENT THEORY OF N. TESLA HAS CHANGE THE LIFESTYLE OF HUMANITY. WITH THE USE OF AC CURRENT THEORY IT BECAME POSSIBLE TO TRANSMIT THE ELECTRICITY AT LONGER DISTANCE AND ALSO TO PRODUCE HIGH AC VOLTAGE IN POWER PLANTS.

    

OHM'S LAW:

THE MOST BASIC LAW AND IMPORTANT LAW OF ELECTRICITY IS OHM'S LAW. THIS LAW STATES THAT "THE CURRENT THROUGH A CONDUCTOR BETWEEN TWO POINTS IS DIRECTLY PROPORTIONAL TO THE VOLTAGE ACROSS THE TWO POINTS". NOW, THE RESISTANCE IS TERMED AS A COMPONENT OF CIRCUIT WHICH OPPOSES THE FLOW OF CURRENT. UNIT OF RESISTANCE IS "OHM". AS RESISTANCE RESISTS THE FLOW OF CURRENT FRICTION OCCURS AND HEAT GETS PRODUCED. THIS HEAT THEN WHICH CAUSES THE VOLTAGE DROP IN CIRCUIT. VOLTAGE IS TERMED AS THE MEASURE OF WORK(PRESSURE) REQUIRED TO MOVE THE CURRENT FROM ONE POINT OF CIRCUIT TO THE OTHER. UNIT OF VOLTAGE IS "VOLTS". FROM THE TWO POINTS OF CIRCUIT ONE POINT HAS HIGHER VOLTAGE VALUE AND OTHER POINT HAS LOWER VOLTAGE VALUE FOR EX. POSITIVE POINT HAS +5V AND NEGATIVE POINT HAS 0V OR CALLED AS "NEUTRAL POINT". TO ALLOW THE FLOW OF CURRENT IN CIRCUIT IT IS NECESSARY TO HAVE NON-ZERO THE POTENTIAL DIFFERENCE BETWEEN POSITIVE AND NEGATIVE POINT. SOMETIME THE NEGATIVE POINT COULD BE NON-ZERO VOLTAGE FOR EX. IF POSITIVE POINT HAS +20V THEN NEGATIVE POINT COULD BE -20V, +10V. AS LONG AS THERE IS A NON-ZERO POTENTIAL DIFFERENCE BETWEEN THE TWO POINT THE CURRENT WILL KEEP FLOWING THROUGH THE CIRCUIT. THE DIRECTION OF THIS CURRENT COULD BE CHANGE IF THE POTENTIAL DIFFERENCE BECOMES NEGATIVE. FOR EX. POSITIVE POINT NOW HAS +10V AND NEGATIVE POINT CHANGED TO -20V THE DIFFERENCE WILL BE 10-20=-10V. THIS WILL CAUSE THE CURRENT TO FLOW IN OPPOSITE DIRECTION.

THE PARAMETERS OF OHM'S LAW -

V = I * R
"V" IS THE APPLIED VOLTAGE IN "VOLTS".
"I" IS THE CURRENT FLOWING THROUGH CIRCUIT  IN "AMPERES".
"R" IS THE RESISTANCE OF THE CIRCUIT IN "OHMS" or "Ω".

BASIC TYPES OF ELECTRICAL CIRCUIT:

MULTIPLE RESISTANCE IN THE CIRCUIT USED TO DIVIDE VOLTAGE OR ALTER THE CURRENT PATH. THERE ARE TWO TYPES OF CIRCUIT DIVISION POSSIBLE USING RESISTANCES, "SERIES CIRCUIT" AND "PARALLEL CIRCUIT".

SERIES CIRCUIT AND PARALLEL CIRCUIT -

THE SERIES CIRCUIT IS IN-LINE WITH POWER SOURCE. THAT IS RESISTANCES HERE ARE CONNECTED IN SERIES WITH VOLTAGE SOURCE. THE CURRENT IS THE SERIES CIRCUIT IS CONSTANT. HOWEVER, THE VOLTAGE NOW GETS DIVIDED BY THE NUMBER OF RESISTANCES. HENCE, IN SERIES CIRCUIT NUMBER OF RESISTANCES CAUSES REDUCTION IN VOLTAGE DEPENDING UPON THE VALUES OF RESISTANCES.

PARALLEL CIRCUIT IS THE CIRCUIT THAT IS DIVIDED INTO DIFFERENT LOOPS OR BRANCHES WITH COMPONENTS ARE ON THE DIFFERENT BRANCH AND POWER SOURCE IS ON THE DIFFERENT BRANCH. IN PARALLEL CIRCUIT THE VOLTAGE IS CONSTANT. HOWEVER, DUE TO THE PRESENCE OF DIFFERENT LOOPS OR BRANCHES IN THE CIRCUIT IT WILL CAUSE CURRENT TO DIVIDE IN EACH BRANCH.

SERIES AND PARALLEL AC CIRCUIT

THE BEST EXAMPLE OF SERIES CIRCUIT IS DECORATION LIGHTS. IT BECOME SO ANNOYING TO SEE WHEN THE DECORATIVE LIGHTS SHUTS DOWN COMPLETELY ONLY BECAUSE OF ONE LAMP IN HUNDREDS IS BROKEN. THIS IS MAINLY BECAUSE ALL THE LAMP NEEDS SAME AMOUNT OF CURRENT TO LIGHT UP AND THE CURRENT NEEDS A CLOSED LOOP TO FLOW THROUGH. BECAUSE OF ONE FAULTY LAMP CIRCUIT TENDS TO GET OPEN AND CURRENTS WILL BECOME ZERO. THIS WILL CAUSE WHOLE SERIES OF LIGHTS TO SHUT DOWN.

HEALTHY SERIES DECORATION LIGHTS

FAULTY SERIES DECORATION LIGHTS

NOWADAYS, PARALLEL CONNECTED DECORATIVE LIGHTS ARE AVAILABLE IN THE MARKET. THIS USUALLY WORKS AS, LAMPS WILL NOW BE DIVIDED INTO DIFFERENT BRANCHES IF ONE LAMP BREAKS DOWN THE ONLY ONE BRANCH THAT OF THE SAME LAMP WILL SHUT DOWN BUT  REST OF THE BRANCHES AND LAMPS WILL REMAIN HEALTHY.

HEALTHY PARALLEL BRANCHES OF DECORATION LIGHTS

ONE FAULTY AND ONE HEALTHY PARALLEL BRANCH OF DECORATION LIGHTS

HOW TO APPLY OHM'S LAW:

WE WILL TAKE COMPONENTS WITH VALUES IN CONSIDERATION AS,

R1 = 300 Ω
R2 = 250 Ω
I  = 5 AMPS (BATTERY CURRENT) DC
V  = 5 VOLTS (BATTERY VOLTAGE) DC
S1 = SWITCH

WE KNOW OHM'S LAW IS V = I * R IT CAN BE USED TO FIND "I",

AS THE CIRCUIT HAS TWO RESISTANCES CONNECTED IN SERIES WE CAN ADD THEIR VALUES TO FIND COMMON VALUE THIS IS CALLED EQUIVALENT RESISTANCE "Req".

NOW,

Req = R1 + R2 ;
    = 300 + 250 ;
Req = 550 Ω.

NOW, WE CAN CALCULATE CURRENT - 

I = V / Req
  = 5 / 550
  = 9 mAMPS

APPLYING OHM'S LAW APPLIED TO SERIES CIRCUIT - 

IN ORDER TO APPLY OHM'S LAW WE WILL TAKE A CIRCUIT IN CONSIDERATION THAT HAS TWO LED LIGHTS AS OUR TWO RESISTANCES "R1" AND "R2" RESPECTIVELY. "S1" WILL BE THE SWITCH OF THE CIRCUIT.
ONCE THE SWITCH IS CLOSED, CURRENT WILL START FLOWING THROUGH THE LOOP. BATTERY SUPPLIES CURRENT OF 5 AMPS HOWEVER THE CIRCUIT LOADS ONLY USES NECESSARY AMOUNT OF IT.

DC SERIES CIRCUIT SUPPLYING TWO LED LAMP LOADS

WE KNOW THE BATTERY VOLTAGE WHICH IS Vs = 5 VDC.

NOW, WE NEED TO CALCULATE THE VOLTAGE DROP ACROSS LED1 AND LED2 THAT IS V1 AND V2 RESPECTIVELY.
WE KNOW OHM'S LAW IS V = I * R ;
AS,

I  = 9 mAMPS
R1 = 300 Ω
R2 = 250 Ω
V1 = I * R1 ; & V2 = I * R2 ;
   = 0.009 * 300 ;    = 0.009 * 250 ;
V1 = 2.7 VOLTS V2 = 2.3 VOLTS

KIRCHHOFF'S VOLTAGE LAW:

THE VOLTAGE DROPS IN SERIES CIRCUIT BRINGS A NEW LAW CALLED KIRCHHOFF'S VOLTAGE LAW IN CONSIDERATION. KIRCHHOFF'S VOLTAGE LAW STATES THAT AN ALGEBRAIC SUM OF VOLTAGES IN CLOSED LOOP IS EQUAL TO ZERO.
KIRCHHOFF'S VOLTAGE LAW USED IN SERIES CIRCUITS AS ONLY SERIES CIRCUITS HAS VOLTAGE DROPS NOT PARALLEL CIRCUITS. IF WE KNOW THE VOLTAGE DROP IN R1 ONLY WE CAN FIND THE VOLTAGE DROP OF R2 WITH THE HELP OF KIRCHHOFF'S VOLTAGE LAW (KVL).
IN KVL WE NEED TO ASSUME ONE CURRENT DIRECTION, WE WILL ASSUME IT AS CLOCKWISE(+VE TO -VE), ALONG WITH POLARITIES OF THE COMPONENTS R1 AND R2 AS SHOWN.

KVL APPLIED TO DC SERIES CIRCUIT

NOW,

Vs = V1 + V2 ; REARRANGING EQUATION ACCORDING TO KIRCHHOFF'S VOLTAGE LAW
Vs - V1 - V2 = 0 ;

        (5) - (I * R1) - (I * R2) = 0 ;

5 - (0.009 * 300) - (0.009 * 250) = 0 ;
5 - (2.7 - 2.3) = 0;

        5 - 5 = 0.

THUS, Vs - (V1 + V2) = 0, HENCE THEORY PROVED.

OHM'S LAW APPLIED IN PARALLEL CIRCUIT -

NOW TO APPLY OHM'S LAW TO A PARALLEL CIRCUIT WE WILL TAKE COMPONENTS AS SERIES CIRCUIT AND CONNECT THEM PARALLEL WITH THE SAME SOURCE.
THIS WILL DIVIDE THE CIRCUIT IN DIFFERENT BRANCHES:

BRANCH 1 HAS R1, 
BRANCH 2 HAS SUPPLY SOURCE AND SWITCH, 
BRANCH 3 HAS R2.

AS WE ALREADY KNOW THE VOLTAGE IN PARALLEL CIRCUIT IS CONSTANT IN ALL BRANCHES. BUT THE CURRENT IN PARALLEL CIRCUIT IS DIVIDED IN EVERY BRANCH WITH VALUE DEPENDING UPON THE RESISTANCE OFFERED BY THE BRANCH.

DC PARALLEL CIRCUIT SUPPLYING TWO LED LAMPS

CALCULATE CURRENT FLOWING THROUGH BRANCH 1 -

I1 = Vs / R1 ;
   = 5 / 300 ;
I1 = 0.017 AMP.

FOR BRANCH 2 THE TOTAL CURRENT USED BY THE CIRCUIT -

It = Vs / Req ;

FOR PARALLEL CIRCUIT  Req CAN BE FOUND OUT BY TAKING ADDITION OF RECIPROCALS OF THE RESISTANCES ;

(1 / Req) = (1 / R1) + (1 / R2) ;
(1 / Req) = (1 / 300) + (1 / 250) ;
(1 / Req) = (0.00733) ;
Req   = (1 / 0.00733) ;
Req   = 136.4 Ω.

NOW,

        It = (5 / 136.4) ;
It = 0.037 AMPS.

CALCULATE CURRENT FLOWING THROUGH BRANCH 3 -

I2 = Vs / R2 ;
   = 5 / 250 ;
I2 = 0.02 AMP.

THE CURRENT GETS DIVIDED IN EACH BRANCH BUT BRANCH WITH LOWER RESISTANCE WILL HAVE HIGHER VALUE OF CURRENT FLOWING THROUGH IT, HENCE THEORY PROVED.

KIRCHHOFF'S CURRENT LAW:

AS WE KNOW, CURRENT IN SERIES CIRCUITS ARE CONSTANT BUT CURRENT IN PARALLEL CIRCUIT IS VARYING, DUE TO THIS ANOTHER KIRCHHOFF'S LAW BROUGHT OUT.
THIS LAW STATES THAT CURRENT ENTERING IN THE NODE WILL BE EQUAL TO CURRENT OUT-COMING FROM THE NODE. THAT IS THE ACTUAL CURRENT IN NODE WILL BE ZERO.

i.e. Iin - Iout = 0.

BEFORE WE SOLVE THIS WITH KCL WE HAVE ALREADY VALUES DETERMINED FROM PARALLEL CIRCUIT ABOVE SO, 

        It = I1 + I2 ;
HERE, It = Iin ;
(I1 + I2) = Iout ;

SO, THE ACCORDING TO THEORY WE CAN SAY THAT, 

It - (I1 + I2) = 0 ;
PUT THE VALUES DETERMINED BY SOLVING PARALLEL CIRCUIT ABOVE,
0.037 - (0.017 + 0.02) = 0 , HENCE THEORY PROVED.

NOW LET US PROVE THIS THEORY WITH KCL -

KCL APPLIED TO DC PARALLEL CIRCUIT

WE ALREADY KNOW THAT,

It = (I1 + I2) ;

WHERE It IS INCOMING CURRENT TO THE NODE AND (I1 + I2) ARE THE CURRENTS OUT-COMING FROM NODE.

FIND THE VALUES OF CURRENTS USING OHM'S LAW ;

It = (Vs / Req) ;
I1 = (Vs / R1) ;
I2 = (Vs / R2)

PUTTING VALUES OF CURRENTS IN EQUATION OF KCL;

It - (I1 + I2) = 0 ;
(Vs / Req) - [(Vs / R1) + (Vs / R2)] = 0 ;
(5 / 136.4) - [(5 / 300) + (5 / 250)] = 0 ; 
(0.036) - [0.036] = 0 ; HENCE THEORY PROVED.

ELECTRICAL POWER EQUATION:

ELECTRICAL POWER IS MEASURE OF ELECTRICAL ENERGY IN WATTS. THE POWER EQUATION IS AS FOLLOWS,

P = V * I ;
WHERE, P = POWER IN WATTS ;
V = VOLTAGE IN VOLTS ;
I = CURRENT ;

THUS DEFINITION OF POWER IS PRODUCT OF VOLTAGE APPLIED TO THE CIRCUIT AND CURRENT FLOWING THROUGH THE CIRCUIT. HOWEVER, FOR AN AC CURRENT CIRCUIT, THERE ARE SOME LOSSES ALSO INVOLVED IN THE ELECTRICAL SYSTEM THAT IS WHEN THE POWER FACTOR TERM COMBINES WITH ELECTRICAL POWER EQUATION.

THE POWER EQUATION FOR AC CIRCUITS IS AS FOLLOWS,

P = V * I * COSФ, 
WHERE, COSФ = POWER FACTOR.

WE CAN USE OHM'S LAW WITH POWER EQUATION TO FIND OUT UNKNOWN VALUES OF VARIABLES. FOR EXAMPLE,

I = V / R ; 

COMBINE THIS WITH POWER EQUATION WE GET,

P = V * (V / R) ;
P = (V^2 / R).

OR

V = I * R ;

COMBINE THIS WITH POWER EQUATION WE GET,

P = (I * R) * I ;
P = (I^2 * R).

USING THIS EQUATION WE CAN FIND THE POWER CONSUMED BY PARALLEL CIRCUIT,

P = (I^2 * R) ;
HERE,
I^2 = It^2 ;
R = Req ;
P = [(It^2) * Req] ;
P = [(0.036^2) * 136.4] ;
P = 183 mWATTS.

SIMILARLY USING OTHER EQUATION,

P = (V^2 / R) ;
HERE,
V^2 = Vs^2 ;
R = Req ;
P = [(Vs^2) / Req] ;
P = [(5^2) / 136.4] ; 
P = 183 mWATTS.