motor selection 1

M/s Help Line (Consulting Engineers) mail: [email protected] 38A, sonagiri, Raisen Road, phone: 0755-5262708 Bhopal 462021 mobile: 9826338127 Consultant to MPERC

THE AUTHOR WORKED IN BHEL BHOPAL FOR 29 YEARS(INCLUDING 8 YEARS EXPERIENCE IN DESIGN AND 21 YEARS EXPERIENCE IN EXECUTION OF CONTRACTS EXECUTION IN THE AREAS OF MOTORS , ALTERNATORS & HYDROPROJECTS, FRAMING SPECIFICATIONS, QA PLANS, ARRANGING STAGE, ELECTRICAL AND FINAL INSPECTION. THIS WRITEUP IS PREPARED WITH A VIEW TO SPREAD THE LEARNINGS GAINED BY EXPERIENCE

(ANY SUGGESTIONS FOR IMPROVEMENT IN WRITE UP ARE WELCOMED)

MOTORS AN OVERVIEW

1. GENERAL CONSIDERATIONS: -

A DETAILED UNDERSTANDING OF TYPE OF MOTORS, MOUNTING, ENCLOSURES, DUTY HELPS IN IDENTIFYING APPROPRIATE TYPE OF MOTOR FOR THE INTENDED APPLICATION. A LARGE POPULATION OF MOTORS RIGHT FROM FRACTIONAL HORSE POWER TO MOTORS UPTO 12 MW ARE IN USE IN VARIOUS INDUSTRIES.

THIS COVERAGE IS PRIMARILY FOCUSED FOR RATINGS ABOVE 150 KW WHERE APPLICATION, MOUNTING ARRANGEMENT, ATMOSPHERIC CONDITIONS PLAY A MAJOUR ROLE. IT IS ESTIMATED THAT YEARLY DEMAND OF MOTORS RANGING FROM 150 KW ONWARDS IS ROUGHLY 1200 TO 1500 EACH YEAR.

MAJOR PLAYERS IN THE INDIAN CONTEST ARE1) BHELWHOSE MARKET SHARE IS APPROXIMATELY 70% FOLLOWED BY 2) CGL, KEC AND OTHERS.

2. MOTORS CLASSIFICATION: -

A) CLASSIFICATION BASED ON TYPE: -

A1) A.C CURRENT INDUCTION MOTORS A) SQUIRREL CAGE INDUCTION MOTORS B) SLIP RING INDUCTION MOTORS C) VARIABLE SPEED DRIVES INDUCTION MOTORS WITH 2 OR 3 WINDINGS FOR DIFFERENT

SPEEDS. 2 WINDING MOTORS WILL GIVE 4 SPEEDS (2 DIFFERENT SPEEDS FOR EACH WINDING WITH STAR AND DELTA CONNECTION)

A2) DIRECT CURRENT MOTORS: -A) WITH SERIES FIELD WINDING B) WITH SHUNT FIELD WINDING C) WITH COMPOUND FIELD WINDING HAVING SHUNT AS WELL

AS SHUNT WINDING.

A3) SYNCHRONOUS MOTORSA) ASYNCHRONOUS MOTORS HAVING SLIP RING WINDING

ALONGWITH DC FIELD WINDING B) SYNCHRONOUS MOTORS WITH DAMPER BAR WINDING AND DC FIELD WINDING.

THESE CAN BE EITHER B1) SALIENT POLE CONSTRUCTION B2) CYLINDRICAL ROTOR CONSTRUCTION.

C) VARIABLE FREQUENCY DRIVES.

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B) CLASSIFICATION BASED ON MOUNTING: - B1 HORIZONTAL MOUNTING

ALL GENERAL PURPOSE MOTORS FOR CONVEYER, CRUSHER, COMPRESSOR, ID FAN, PA FAN, SECONDARY AIR FAN, EXHAUST, AND SIMILAR APPLICATION SUCH MOTORS ARE IN COMMON USE.

B2) VERTICAL MOUNTINGTHESE ARE GENERALLY USED FOR PUMP APPLICATION, SCREW DOWN APPLICATION, OR VARTICAL BORING, ON BOARD DRILL APPLICATIONS. SOME TIMES FOR PUMPS HORIZONTAL MOTORS ARE ALSO IN USE.

B3) SPECIAL MOUNTING APPLICATIONS: - REQUIRING SUITABIULITY TO OPERATE AT AN ANGLE SAY FOR SUBMARINE OR FRIGATE APPLICATIONS. THIS REQUIREMENT IS CALLED SWING /RANGE. THESE MOTORS ARE ALSO REQUIRED TO BE SUITABLE FOR RESITANCE TO HEAVY SHOCKS GNERATED DUE TO SHELLING OF EXPLOSIVES. (A SHOCK LEVEL OF 7G) MAY BE REQUIRED WHICH IN LAY MANS TERMS CAN BE CONSIDERED EQUIVALENT TO FALLING OF AN EQUIPMENT FROM A HEIGHT OF 9 METERS FROM THE GROUND AND AFTER WHICH THE EQUIPMENT SHOULD STILL BE ABLE TO PERFORM FOR ITS INDENTED DUTY)

OTHER APPLICATIONS ARE TARPIDOES, GUN CONTROL ETC WHERE SUCH SPECIAL PURPOSE MOTORS ARE REQUIRED. THIS CATEGORY ALSO INCLUDE SPECIAL PURPOSE MOTORS REQUIRED FOR BATTLE TANKS. THESE ARE TOTALLY ENCLOSED MOTORS PROVIDED WITH SPECIAL BEARINGS. THESE MOTORS ARE REQUIRED TO SWING UPWARD DOWNWARD AND AT DIFFERENT ANGLES TO VERTICAL AXIS.

C) CLASSIFICATION BASED TYPE OF ENCLOSURE: -

TYPE OF ENCLOSURE WILL DEPEND UPON THE ENVIRONMENT IN WHICH THE MOTOR IS REQUIRED TO OPERATE .

C1) AN IP 23 SPDP/DP TYPE MOTOR CAN BE USED IN A CLEAN ATMOSPHERE FREE OF DUST, AND NON-HAZORDOUS ATMOSPHERE SAY IN THE POWER HOUSE OR CLEAN WORK SHOP. THE HEAT TRANSFER FROM HOT PARTS OF MOTOR TO THE ATMOSPHERE IS BY CONVECTION PROCESS. THE PROCESS INVOLVES ENTRY OF AIR FROM ONE END AND EXIT AT OTHER END. GENERALLY AIR INTAKE IS FROM NON-DRIVE END AND OUTLET IS FROM DRIVE END.

C2) IP 44 DUCT VENTILATED MOTOR IN THIS TYPE OF CONSTRUCTION, INLET AIR IS FED TO THE MOTOR AT NDE SIDE THROUGH A DUCT. AT THE BIGGNING OF DUCT A POWERED FAN IS PROVIDED WHICH FORCES FRESH ATMOSPHERIC AIR INTO THE DUCT. OUT LET AT DE SIDE IS EITHER THROUGH DUCT OR RELEASED IN THE MOTOR SURROUNDING.

FOR MULTI SPEED MOTORS WITH CONSTANT TORQUE APPLICATION, EXCEPT FRICTION AND WINDAGE LOSSES (WHICH ARE PROPERTIONAL TO SPEED), OTHER LOSSES REAMIN CONSTANT NEEDING SAME AMOUNT OF AIR AT ALL SPEEDS FOR EFFECTIVE COOLING. FOR SUCH ARRANGEMENT THIS YPE OF DUCT VENTILATED COOLING IS BEST PROPOSITION PROVIDED THE SURROUNDING ATMOSPHERE IS CLEAN AND NON HAZARDOUS.

C3) IP54 PROTECTION MOTORS ARE TEFC/TETV/CACA/OR CACW ENCLOSURE MOTORS, WHICH ARE EXTENSIVELY USED FOR HUMID, DUSTY, AND CONTAMINATED AIR ATMOSPHERE. THE COMMON TYPE IS: -

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C3.1) TETV/TEFC (IP54/IP55 CLASS OF PROTECTION): - CALLED TOTALLY ENCLOSED TUBE VENTILATED OR TOTALLY ENCLOSED FAN COOLED. THE INSIDE OF THE MOTOR IS CIRCULATED FROM INSIDE OF MOTOR TO THE SPACE (OR SHELL) WHICH HOUSES TUBES. THE HEAT OF INSIDE AIR IS TRANSFERRED TO THE TUBES BY CONDUCTION PROCESS THE OUTSIDE AIR IS FORCED THROUGH THESE TUBES BY FANS MOUNTED ON OUTSIDE PORTION OF THE MOTOR. THE TRANSFER OF HEAT THROUGH THESE TUBES IS BY PROCESS OF CONVECTION.

BLOCK DIAGRAM OF A HORIZONTAL TETV MOTOR

AUX T.B. MAIN T.B, NEUTRAL T.B. MAIN TB

C TRIFURCATING BOX A B

TOTALLY ENCLOSED TUBE VENTILATED (OR ALSO CALLED TOTALLY ENCLOSED FORCED COOLED MOTORS ARE BEST SUITED FOR DUSTY/HUMID & SLINE ENVIRONMENT. THE SECTIONAL LAYOUT OF THE MOTOR BELOW SHOWS VARIOUS MAJOR PARTS AND COOLING

TUBE ARRANGEMENT. TUBES IN THE STATOR FRAME EXTERNAL FAN COVER

ENDSHIELD

SHAFT

BEARING HOUSING

WOUND STATOR ROTOR INTERNAL EXTERNALWITH CAGE FAN FAN

HERE THE TWO INTERNAL FANS CIRCULATE THE INTERNAL BETWEEN ROTOR AND WOUNDSTATOR THROUGH THE SHELL IN THE FABRICATED FRAME. WHILE EXTERNAL FAN TAKESSURROPUNDING OUTSIDE AIR AND PUSHES THROUGH THE COOLING TUBES HOUSED IN THEFABRICATED FRAME.

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SINCE IN THIS TYPE OF CONSTRUCTION COOLING TUBES ARE HOUSED ALL AROUND THEWOUND STATOR CAPSULE, THE COOLING IS EFFECTIVE. THESE MOTORS HAVE HIGHER ORDEROF EFFICIENCY COMPARED TO CACA OR TOTALLY ENCLOSED TYPE CONSTRUCTION MOTORS.

C3.2) CACA TYPE INDUCTION MOTORSTHESE MOTORS ARE PROVIDED WITH TOP OR SIDE MOUNTED AIR TO AIR HEAT

EXCHANGERS. EQUIPMENT HOT INSIDE AIR PASS THROUGH THE COOLER SHELL AND HEAT TRANSFER TAKES PLACE THROUGH HEAT EXCHANGER TUBES WHICH CARRY SURROUNDING ENVIROMENTAL COOL AIR.

CACA COOLER

SHAFT

FRONT VIEW

ROTORWOUND STATOR INTERNAL FAN EXTERNAL FAN

THE DIFFERENCE BETWEEN TETV AND CACA MOTORS IS THAT, IN CASE OF TETV/TEFC MOTOR THECOOLER TUBES ARE SORRUNDED ALL OVER AROUND THE WOUND STATOR, WHILE IN CASE OFCACA MOTORS, THE TUBES ARE HOUSED IN TOP MOUNTED COOLER.

FOR THE SAME RATING AND SPEED CACA MOTORS WILL HAVE LESS SHAFT CENTRE HEIGHTCOMPARED TO TETV OR TEFC MOTORS. THEREFORE WHERE EVER SHAFT CENTRE HEIGHT ISLIMITATION, ONE CAN GO FOR CACA MOTORS.

REGULAR CLEANING OF COOLER TUBES IN BOTH CASES IS ESSENTIAL DURING ROUTINEMAINTENANCE SINCE ACCUMULATION OF DUST AND SCALE FORMATION MAY REDUCE HEATTRANSFER CAPABILITY OF COOLER RESULTING REDUCED PERFORMANCE AND HIGHERTEMPERATURE RISE OF THE MOTOR.

IP54/IP55 MOTORS WITH SPEED VARIATION.

SINCE BOTH TETV OR CACA MOTORS HAVE SHAFT MOUNTED FAN FOR EXTERNAL AIR CIRCUIT,WHERE EVER SPEED VARIATION IS INVOLVED, AT REDUCED SPEED ONLY FRICTION LOSSES WILL REDUCE WHILE LOAD LOSSES WILL PRACTICALLY REMAIN SAME.

AT REDUCED SPEED VELOCITY OF INTERNAL CIRCULATING AIR AS WELL AS EXTERNAL CIRCULATINGAIR WILL REDUCE WHICH WILL AFFECT HEAT TRANSFER RESULTING HIGHER TEMPERATURE RISE THEN PERMISSIBLE. THIS WILL EFFECT ON MOTOR PERFORMANCE. IN SUCH CASE BLOWERS ARE PROVIDED ON THE COOLERS WHICH OPERATE ON SEPARATE 230/415 VOLTS SUPPLY.

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THUS BARING REDUCTION IN CAPACITY DUE TO REDUCED INTERNAL AIR CIRCULATION, THE MOTOR(S) CAN OPERATE AT LOWER SPEEDS ALSO GIVING SAME PERFORMANCE.

EXTERNAL BLOWER UNIT OPERATING CONTINUOUSLY THROUGH SEPARATE 230/415 VOLTS SUPPLY

TOTALLY ENCLOSED MOTORS (IP55/IP54 PROTECTION)

THE MOTORS OF SMALLER RATINGS SAY UPTO 250 KW CAN BE OFFERED IN TOTALLY ENCLOSEDFRAMES. THE FRAMES ARE GENERALLY OF ROUND CONSTRUCTION (CAST OR FABRICATED)SINCE HEAT GENERATED DUE TO MOTOR LOSSES IS POSSIBLE TO DISSIPATE THROUGH ONLYSTATOR FRAME, THE STATOR FRAME IS PROVIDED WITH LARGE NO OF FINS TO INCREASE HEATTRANSFER SURFACE AREA. THIS TYPE OF CONSTRUCTION IS COMMONLY KNOWN.

THESE MOTORS ARE MOST SUITED WHERE OPERATIONS ARE SUBJECTED TO OPEN ATMOSPHEREHAVING NO SHADE (E.G. PUMP HOUSES/ EXCAVATION/ MUD COLLECTORS ETC).

C3.3) INCREASED SAFETYSUCH TYPE OF MOTORS ARE REQUIRED WHERE TYPE E PROTECTION ISREQUIRED. PRIMARILY THESE MOTORS CAN BE TETV/TEFC/CACW/CACATYPE BUT JOINTS AND MATCHING PARTS SHOULD BE PERFACT TO AVOIDANY CHANCE OF INGRESS OF OUTSIDE AIR TO COME IN CONTACT WITHINSIDE AIR OF THE MOTOR

C3.4) FLAME PROOF MOTORS/PRESSURISED ENCLOSURETHESE ARE SPECIAL PURPOSE MOTORS, USED IN INFLAMABLE AREA OFOPERATION SAY GAS /OIL PRODUCING UNITS WHERE A LITTLE SPARK CANRESULT GENERATION OF FIRE DUE TO HAZORDOUS ATMOSPHERE PRONETO FIRE. THESE MOTORS USE EVEN ALL TERMINAL BOXES/AUX BOXESWHICH IS FLAME PROOF. EACH AND EVERY MOTOR IS REQUIRED TO BE TESTED AT CMRI/DHANBAD FOR ASCERTAINING ITS WORTHYNESS FOR WORKING IN SUCHATMOSPHERE.

WHERE EVER FLAME PROOF MOTORS ARE NOT POSSIBLE TO SUPPLY (SAY IN CASE OF LARGE RATINGS, OTHER WAY IS TO PRESSURISE THE ENCLOSURE OF THE MOTOR. THISCONSIST OF OPERATION OF MOTOR WITH INSIDE PRESSURE HIGHER THEN OUT SIDEATMOSPHERIC PRESSURE SO THAT OUTSIDE INFLAMABLE GASES DO NOT ENTER INTO THE MOTOR (SINCE MOTOR INSIDE PRESSURE IS HIGHER) FOR SUCH SYSTEM SPECIAL PURGING UNITS ARE FITTED ON THE MOTOR WHICH ARE PREFERRED TO MECHANICALLY OPERATED (FOR AVOIDING ANY SPARKS ETC) AND ONCE INSIDE PRESSURE IS ATTAINED THE BREAKERWILL MAKE ON THE SUPPLY. PRESSURE INSIDE MOTOR IS REQUIRED TO REMAIN HIGHERTHEN OUTSIDE THROUGHOUT THE OPERATING TIME OF THE MACHINE.

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C) CLASSIFICATION BASED ON SUPPLY VOLTAGE DEPENDING ON AVAILABILITY OF SUPPLY VOLTAGE THE MOTORS CAN BE CLASSIFIED AS FOLLOWS: - 1 AS PER AMERICAN/EUROPEAN PRACTICE: - A) LT RANGE MOTORS 230 VOLTS, 415 VOLTS B) MEDIUM VOLTAGE RANG- 690 VOLTS TO 3300 VOLTS C) HT RANGE MOTORS 6600 VOLTS AND 11000 VOLTS. 2) AS PER INDIAN PRACTICE: -

LT RANGE MEANS 230 VOLTS, 415VOLTS AND 690 VOLTS AND HT MEANS 3300, 6600 AND 11000 VOLTS RANGE.

D) MOTORS DUTY E1) SHORT TIME DUTY E2) INTERMITTANT DUTY E3) CONTINUOUS DUTY. GENERALLY BUYERS SPECIFY CONTINUOUS DUTY ONLY.

3 SELECTION OF MOTOR AND DEFINING SPECIFICATIONS: -

IDENTIFYING REQUIREMENTS IS REALLY A CRITICAL TASK. THIS INVOLVES: - A) ENVIRONMENTAL CONDITIONS B) SUPPLY VOLTAGES AND FREQUENCY & VARIATION C) LOAD DETAILS D) CONTROLS/SIGNALS REQUIRED FROM MOTOR INSTRUMNETS FOR VARIOUS CONTROLS E) OTHER STATUTORY REGULATORY REQUIREMENTS. F) OTHER PARAMETERS (NO OF START/STOPS/LOAD CYCLE ETC)

3.1 FIRST 3 PARAMETERS BECOME THE GUIDE LINES FOR FRAMING SPECIFICATIONS AND NEED CAREFUL CONSIDERATIONS. A) ENVIRONMENTAL CONDITIONS INCLUDE AMBIENT CONDITIONS i.e. MAX AMBIENT TEMPERATUR, LATITUDE AND ALTITUDE, TYPE OF ATMOSPHERE (DUSTY/HUMID, SLINE, CHEMICALLY ACTIVE, HAZARDOUS ETC). ENVIRONMENTAL CONDITIONS HAVE BEARING ON TYPE OF ENCLOSURE TO BE SELECTED e.g. FOR HAZARDOUS ATMOSPHERE PRESSURISED ENCLOSURE MOTORS AND IN CASE OF INFLAMABLE ATMOSPHERE (SAY IN REFINERY ETC) FLAME PROOF MOTORS MAY BE REQUIRED. THE TYPE OF ENCLOSURE WILL DECIDE ABOUT THE SIZE OF THE MOTOR AND THE COST AS WELL.

SIMILARLY HIGHER THE AMBIENT, LOWER WILL BE THE TEMPERATURE RISE LIMITS AVAILABLE. FOR EXAMPLE, FOR A CLASS F INSULATED MOTOR, WITH AMB CONDITION OF 20 DEG C, THE ALLOWED TEMP IS 120 DEG (WITH CLASS B LIMITS) FOR THE WINDING THIS MEANS TEMPERATURE RISE CAN GO UPTO 100 DEG C OVER 20 DEG AMBIENT. AT SOME OTHER GEOGRAPHICAL POSITION HAVING AMBIENT OF 50 DEG C, IF FOR SAME RATING IF MOTOR IS TO BE SELECTED THEN ALLOWED TEMP RISE WOULD BE ONLY 70 DEG C. EVENTUALLY A HIGHER SIZE MOTOR WILL BE REQUIRED.

B) LOAD DETAILS FROM ENERGY MANAGEMENT/CONSERVATION POINT OF VIEW LOAD DETAILS PLAY A VITAL ROLE? IN SELECTING A MOTOR RATING. THE ACTUAL LOAD REQUIREMENT AT DUTY POINT MAY BE MUCH LOWER THEN THE MOTOR RATING. THIS WILL RESULT IN POOR LOADING OF DRIVE, LOWER OPERATING EFFICIENCY, AND HIGHER ENERGY LOSSES.

FOR EXAMPLE, IN A BOWL MILL (IN A POWER PLANT) THE LOAD REQUIREMENT MAY BE OF SAY 165 KW AT DUTY POINT. HOWEVER, THE BOWL MILL SUPPLIER WILL TAKE 20% MARGIN AND WILL INDICATE A RATING OF 198 KW. THE CONSULTANT OF THE BUYER WILL TAKE ANOTHER 10% MARGIN ARRIVING AT A RATING OF 220 KW AND WILL FLOAT ENQUIRY FOR ABOVE RATING. THE MOTOR SUPPLIERS DESIGN DEPARTMENT WILL TAKE ANOTHER SAFETY MARGIN OF 10 % AND WILL FINALLY DESIGN THE MOTOR FOR 240 KW RATING. GENERALLY DESIGNERS DESIGN THE MOTOR AT THIS RATING FOR OPTIMAL EFFICIENCY/POWER FACTOR.

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THE RESULT IS EVEN AT 165 KW DUTY POINT (REAL REQUIREMNT) THE PERCENTAGE LOADING WILL ONLY BY 69%. NATURALLY THIS WILL RESULT IN POOR PERFORMANCE OF MOTOR AND HIGHER ENERGY CONSERVATION.

AS SUCH IT IS IMPORTANT ON THE PART OF BUYER/USER TO APPROPRIATELY SELECT THE RATING TAKING ALL ASPACTS INTO CONSIDERATIONS.

C) SUPPLY SYSTEM SUPPLY SYSTEM INCLUDES, SYSTEM VOLTAGE, FREQUENCY AND VARIATION IN VOLTAGES AND FREQUENCY. THESE SHOULD BE STIPULATED CORRECTLY AS THESE ARE IMPORTANT FROM THE POINT OF VIEW OF MOTOR DESIGN.

IN SOME CASES BUYERS SPECIFY 11 KV MOTOR OPERATING VOLTAGES. HOWEVER IF POSSIBLE IT WILL BE PREFERABLE TO HAVE A STEP DOWN TRANSFORMER SO THAT 6600 VOLTS SUPPLY IS AVAILABLE ACROSS MOTOR TERMINALS. THE REASON IS ALMOST ALL MANUFACTURERS NOW A DAYS USE CLASS F INSULATION SYSTEM COMMON FOR ALL VOLTAGES. BUT FOR 11 KV SYSTEMS, DUE TO INCREASED INSULATION THICKNESS SPECIAL VPI TECHNIQUES ARE TO BE IMPLEMENTED INCREASING THE COSTS. FURTHER 11KV WINDINGS ARE DIFFICULT TO REPAIR ALSO.

FOR THE SAME RATING, IN GENERAL, WHILE THERE IS NO REDUCTION IN SIZE OF THE MOTOR, THE COST OF 11KV MOTOR MAY BE HIGHER BY 10 TO 15% COMPARED TO A 6.6 KV MOTOR.

D) OTHER PARAMETERS: -OTHER PARAMETERS LIKE NO OF STARTS, STOPS, STARTING CURRENT LIMITATION, AXIAL THRUST IF ANY ARE ALSO IMPORTANT FROM DESIGN POINT OF VIEW AND NEED TO BE SPECIFIED IN THE TENDER SPECIFICATIONS.

A FORMAT OF TECHNICAL REQUIREMENTS WHICH ARE REQUIRED TO BE SPECIFIED ARE FURNISHED BELOW WHICH COULD BE HELP FUL TO USERS WHILE RAISING ENQUIRY:-

HELP LINE CONSULTING ENGINEERS INFORMATION REQUIRED FOR ARRANGING OFFER FOR MOTORS

NO. DESCRIPTION1 APPLICATION 2 MACHINE DESCRIPTION 3 RATING (KW) / SYNCHRONOUS SPEED 4 SUPPLY SYSTEM PARAMETERS:- 4.1 SUPPLY VOLTAGE 4.2 VARIATION IN VOLTAGE 4.3 VARIATION IN FREQUENCY 5 TYPE OF MOTOR REQUIRED(SLP RING/CAGE/VFD) 6 MOUNTING (HORIZONTAL/VERTICAL/SPECIAL INCLINED) 6 ENCLOSURE (TETV/TEFC/CACA/CACW/SPDP/DP/DUCT VENTILATED) 7 PROTECTION CLASS (IP23/IP44/IP55)FLAME PROOF/INCREASED SAFETY 8 INSULATION CLASS / TYPE(F/B) 9 SITE CONDITIONS:- 9.1 SITE MAX AND MIN AMBIENT 9.2 HUMIDITY 9.3 TYPE OF ATOMOSPHERE(CLEAN/DUSTY/SUSTABLE TO

FIRE(INFLAMABLE GASES ETC) 9.4 ALTITUDE/LATITUDE(FROM MSL)(IF NOT FURNISHED WE WILL

ASSUME IT IS LESS THEN 1000M ABOVE MSL)

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10 LOAD DETAILS

10.1 TYPE OF LOAD(CONVEYER/CRUSHER/ID FAN/PA FAN/PUMP/COMPRE- SSOR/SCREW/MILL/ANY OTHER)

10.2 TYPE OF COUPLING(FLEXIBLE/FLUID/TRACTION/RIGID/V BELT) 10.3 LOAD CURVE IF ANY 10.4 LOAD GD SQ/INERTIA (MKSQ) 11 STARTING CONDITIONS IF ANY:_ 11.1 TYPE OF STARTING- DOL/SOFT STARTER/REACTANCE STARTING 11.2 STARTING CURRENT(IF NOT FURNISHED WE SHALL QUOTE MOTOR

WITH 600% FLC SUBJECT TO IS TOLERANCE) 11.3 STARTING TORQUE REQUIREMENT. 12 DETAILS OF ESSENTIAL ACCESSORIES 12.1 WINDING RTDS-PT 100 12.2 BEARING RTDS-PT 100 12.3 BEARING DIAL THERMAMETERS. 12.3 SPACE HEATERS (240 V, 1PH AC) 12.4 STATOR TB - PSTB / PH, SEP, / ELASTIMOLD / FL.PROOF 12.5 NEUTRAL TB- PSTB / NON-PSTB WITH / WITHOUT CT MOUNTING 12.6 ROTOR TERMINAL BOX(ONLY IN CASE OF SLIP RING MOTOR) 12.7 AUXILIARY TERMINAL BOX FOR RTDS & BTDS 12.8 ANY OTHER REQUIREMENT (FOUNDATION BOLTS ETC)

RATING LIMITS FOR 415 VOLTS OPERATING VOLTAGE:-

MOTOR OPERATING VOLTAGES OF 415 VOLTS ARE SUITABLE FOR LOWER RATINGS ONLY. FOR HIGHER RATINGS EITHER 3300 VOLTS, 6600 VOLTS OPERATING VOLTAGES ARE PREFERABLE.

TO THE EXTENT POSSIBLE FOR HIGHER RATINGS(NORMALLY BEYOND 750KW)SELECTION OF LT (415 VOLTS OR 690 VOLTS) MOTORS SHOULD BE AVOIDED BECAUSE MOTORS WITH SUCH LOW VOLTAGES WILL BE REQUIRED TO BE DESIGNED WITH THICKER WINDING COPPER CONDUCTOR CROSS SECTION, REDUCING PUNCHING TEETH WIDTH . ALSO THE THICKER COIL CROSS SECTION WILL INCREASE OVER HANG LENGTH RESULTING OVER SIZING OF MOTOR. ALSO THERE WILL BE PROBLEMS IN MAIN AND NEUTRAL TERMINATION THROUGH TERMINAL BOXES. SUCH MOTORS MAY NEED HIGHER DIA CABLES WHICH MAY AGAIN BE COSTLY AFFAIR. IN GENERAL LT MOTORS WITH CABLES/TERMINATION/BREAKERS ETC(CONSIDERING SYSTEM IN TOTALITY) MAY BE COSTLY PROPOSITION AS COMPARED TO 3.3 KV OR 6.6 KV MOTORS.

3.2 ENCLOSURE:-

SELECTION OF ENCLOSURE WILL DEPEND ON THE ENVIRONMENTAL CONDITIONS WHICH CAN BE CLASSIFIED AS FOLLOWS:-

@ FOR CLEAN NORMAL ATMOSPHERE SELECTION OF SPDP/DP MOTOR WILL BE ECONOMIC.

@ FOR DUSTY/HUMID/CONTAMINATED/ CORROSIVE ATMOSPHERE IT IS PREFERABLE TO GO FOR TEFC/TETV/CACA OR CACW MOTORS.

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IF RATING AND SIZE PERMITS AND THERE IS NO SUCH CONDITION OF LIMITATIONOF SHAFT CENTRE HEIGHT THEN IT IS PREFERABLE TO SELECT A TEFC/TETV COMPARED TO A CACA MOTOR, BECAUSE THE COOLING TUBES ARE PLACED ALLROUND THE STATOR CORE PROVIDING UNIFORM COOLING THROUGH OUT THE COREPERIPHERY. FURTHER CG OF THE MOTOR WILL REMAIN NEAR TO THE SHAFTCENTRE AXIS THEREBY GIVING HIGHER MOTOR STABILITY FROM GRAVITATIONALSTABILITY POINT OF VIEW

WHEN EVER SHAFT CENTRE HEIGHT IS A LIMITATION THE OTHER ALTERNATIVE IS TO BUY A CACA MOTOR. THIS MOTOR IS ALSO TO IP 54/55 DEGREE OF PROTECTIONBUT IN THIS CASE ALL THE TUBES (WHICH OTHER WISE ARE SPREAD THROU-OUTPERIPHERY OF STATOR CORE) ARE BUNDLED IN THE COOLER CASING. THIS COOLER ISMOUNTED ON TOP OF THE MOTOR. CACW ENCLOSURE IS ANOTHER VERSION IN WHICHWATER COOLED COOLER IS PLACED ON TOP OF THE MOTOR

IN BOTH (i.e.) CACA OR CACW CONSTRUCTION MOTORS, THE FRAME IS OF RECTANGULARCONSTRUCTION(BOX TYPE) WITH COOLER MOUNTED ON TOP OF MOTOR

IN GENERAL FOR MOTOR OF SAME RATING, VOLTS AND SPEED, A TEFC/TETV MOTOR WILLBE OF LARGEST SIZE, THEN A CACW/CACA MOTOR WHICH WILL BE LARGER THEN ASPDP/DP MOTOR. INOTHER WORDS, FOR SAME FRAME, MORE POWER CAN BE PACKED IN ASPDP/DP MOTOR AS COMPARED TO CACW/CACA AND TEFC/TETV MOTOR.

@ FOR LARGE SIZED MOTORS TETV/TEFC MOTORS MAY NEITHER BE AVAILABLE NORECONOMIC AND THEREFORE GENERALLY BUYERS GO FOR CACA/CACW MOTORS

@ FOR VERTICLE MOTORS USED FOR PUMP/DRILL/SCREW DOWN APPLICATIONIT WILL BE WORTHWHILE TO GO FOR A TETV/TEFC MOTOR HAVING COOLINGTUBES ALL ROUND THE STATOR CORE. THE ADVANTAGE OF SUCHCONSTRUCTION IS THAT, IN TETV/TEFC CONSTRUCTION FOR VERTICAL MOTORSCG OF THE MOTORS PASSES THROUGH THE CENTRE OF THE SHAFT RESULTING ABALANCED OPERATION(IN CASE OF VERTICLE MOTORS PUMP AND MOTOR SHAFTCG SHAOULD PASS IN CENTRAL VERTICAL AXIS . IN SUCH MOTORS CACA/CACWMOTORS SHOULD ONLY BE USED IF TETV/TEFC OPTION IS NOT AVAILABLE.BECAUSE, DUE TO ONE SIDE OF COOLER MOUNTED ON MOTOR FRAME CG OFMOTOR WILL SHIFT AWAY FROM CENTRE OF SHAFT AND MAY RESULT VIBRATION

A TEFC TYPE MOTOR HAVING COOLING A CACA MOTOR HAVING SIDE MOUNTEDALL ROUND STATOR IN FABRICATED ON ONE SIDE OF SQUARE FRAME MOTOR FRAME SUPPORTING WOUND STATOR

PUMP PUMP

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A TETV MOTOR FOR SUCH VERTICAL APPLICATIONS MAY HAVE BETTER OPERATIONAL PERFORMANCE COMPARED TO A CACA MOTOR.

@ FLAME PROOF AND INCREASED SAFETY MOTORS GENERALLY WARRANT MORE ASSOCIATION AND CONSULTATION WITH THE MANUFACTURERS, AND THEIR SELECTION SHOULD BE ON MUTUAL DISCUSSIONS AMONG BUYER AND MANUFACTURER..

3. TEMPERATURE RISE CONSIDERATIONS

THE MAIN CAUSE OF RISE IN TEMPERATURE IS COPPER LOSS IN WINDING DUE TO WINDING RESISTANCE, STRAY LOAD LOSS AND NO LOAD LOSS (WHICH COVERS FRICTION WINDAGE LOSS+CORE LOSS+ LOSS ES IN BEARINGS ).

WHILE NO LOAD LOSS IS CONSTANT FOR A ROTATING EQUIPMENT, LOAD LOSS(WHICH ISCOPPER LOSS IN THE WINDING AND STRAY LOAD LOSS VARIES WITH THE SQ OF THE CURRENT FLOWING THROUGH THE WINDING. THIS IS THE LOSS WHICH IS IN MAJORITY IS RESPONSIBLE FOR THE TEMPERATURE RISE OF THE MACHINE. CONSTANT HEATING UP AND PROLONGED USE OF MACHINE RESULTS INTO AGING OF INSULATION AND CORE OF THE MACHINE RESULTING REDUCTION OF PERFORMANCE AND LIFE LEVELS ORIGINALLY DESIGNED/INDENTED. THEREFORE SHOULD HAVE SUFFICIENT THERMAL RESERVES FOR ITS PROLONGED CONSISTANT PERFORMANCE BY AND LARGES MODERN PRACTICE IS TO PROVIDE CLASS F INSULATED MOTORS( WITH ROLL IMPREGNATION OF VACCUM PRESSURE IMPREGNATION). HOWEVER IT IS IN THE INTEREST OF THE MOTOR LIFE THAT TEMPERATURE RISE LIMIT SHOULD BE UPTO CLASS B ONLY.

IT IS ESTIMATED THAT FOR EVERY 10 DEG RISE IN TEMPERATURE MORE THEN THE SPECIFIEDLIMIT, THE LIFE OF MOTOR REDUCES BY 12 MONTHS. AND SINCE A MOTOR IS REQUIRED TO SERVE FOR A LONGER TIME IT WILL BE A GOOD PRACTICE TO HAVE MAX WINDING TEMPERATURE OF ONLY 120 DEG (BY RESISTANCE METHOD) (KEEPING 10 DEG C MARGIN FOR HOT SPOT TEMPERATURE.

MOTORS/GENERATORS ARE AVAILABLE IN VARIOUS CLASS OF INSULATIONS MOST COMMON REPUTED MAKE BEING IN CLASS B AND CLASS F. ( TRACTION MOTORS ARE ALSO AVAILABLE WITH CLASS H INSULATION SYSTEM.) LEAVING A MARGIN FOR THE HOT SPOT TEMPERATURE, THE ALLOWED TEMPERATURE RISE LIMITS FOR CLASS B AND F INSULATION AS PER VARIOUSSTANDARDS ARE AS FLLOWS:- CLASS OF INSULATION...B.F ALLOWED TEMP RISE(OVER 40 DEG C AMB)..80 DEG C.105 DEG C BOTH MEASURED BY RESISTANCE MEASUREMENT OF WINDING IN HOT CONDITION

MACHINES REQUIRED WITH TEMP CLASS T3 AND T4 NEED SPECIAL DESIGN CONSIDERATIONS AND NEED TO BE REFERRED TO CONSULTANTS/DESIGNERS OF MANUFACTURERS.

4. MOTOR STARTING CONDITIONS:-

IF NOT SPECIFIED, MOTOR MANUFACTURERS, QUOTE FOR SQ.CAGE INDUCTION MOTORS SUIITABLE WITH STARTING CURRENT APPROX 600% FULL LOAD CURRENT SUBJECT TO TOLERANCE (WHICH PERMITS STARTING CURRENT UPTO 720% FLC). THUS DURING STARTING THE SYSTEM MAY BE SUBJECTED TO SUBSTANTIAL VOLTAGE DIP (SINCE WHEN AN INDUCTION MOTOR IS STARTED WITH DIRECT ON LINE STARTING, DUE TO POOR STARTING POWER FACTOR WHICH COULD BE OF THE ORDER OF 0.2 TO 0.3, THERE IS SUBSTANTIAL VOLTAGE DIP, AND THIS MAY RESULT TRIPPING OF THE BREKAER IF DUE CARE IS NOT TAKEN.

NOW A DAYS SOFT STARTERS ARE AVAILABLE WHICH PROVIDE INITIAL RESISTANCE TO THE HIGH STARTING CURRENT AND THUS ALLOW SMOOTH STARTING OF THE MOTOR BY LIMITING INITIAL STARTING CURRENT.

CONT..PAGE 11/-


CURRENT 600% FLC

DIRECT ON LINE STARTING

SOFT STARTING

TIME/SPEED

MECHANICALSTRESS

SURGE ON RAPID ACCELERATION DECELERATION DOL STRATING

SURGE REDUCTION WITH GRADUAL ACCLERATION / DECELERATION SOFT STARTING

AS SUCH IN CASE OF ANY STARTING CURRENT LIMITATION, IT SHOULD BE INDICATED AT THE TENDER STAGE ITSELF AS IT HAS BEARING ON DESIGN AND FRAME SELECTIONOF THE MOTOR. IF THIS CONDITIONIS INDICATED AT THE TENDER STAGE, THE TENDERER SHALLBE ABLE TO SELECT PROPER FRAME FOR THE INDENTED RATING THUS AVOIDING PROBLEM ATCOMMISSIONING/EXECUTION STAGE.

IN CASE OF HIGH STARTING TORQUE REQUIREMENT, THE SAME SHOULD BE INDICATED AT THETENDER STAGE. FOR A HIGH STRATING TORQUE REQUIREMNT CONDITION, THE TENDERER MAYHAVE TO SELECT A DOUBLE CAGE INDUCTION MOTOR HAVING 2 CAGE WINDINGS ON THE ROTOR.

5. EFFECT OF AMBIENT AND ALTITUDE:-IN TROPICAL CLIMATES LIKE IN INDIA/AND ASIAN REGION AMBIENTS MAY VARY FROM 10 TO 50 DEGC WITH VARIED HUMIDITY.

HOWEVER IN EUROPE AND AMERICA WHERE THERE ARE EXTREME COLD CLIMATES WHICH MAYHAVE AMBIENTS VARYING FROM 35 DEG C TO 20 DEG C WITH HUMIDITY ALSO VARYING UPTO 95%SUCH CONDITIONS ARE ENTIRELY DIFFERENT FROM COUNTRIES LIKE INDIA/AND ASEANCOUNTRIES AND THEREFORE AMBIENT, HUMIDITY, ALTITUDE AND SUCH CONDITIONS SHOULDCLEARLY BE SPECIFIED BY THE BUYER AT THE TENDER STAGE.

CONT..PAGE 12/-

M/S HELP LINE(CONSULTING ENGINEERS) PAGE 12/-

IN ANY CASE , HOWEVER BUYER IS REQUIRED TO SPECIFY ONLY THE ENVIRONMENTAL CONDITIONS AND IT IS OBLIGATORY ON THE PART OF TENDERER FOR SELECTION AND DESIGN OF MOTORS/GENERATORS AFTER IMPLEMENTING NECESSARY CORRECTIONS TO THIS EFFECT BEFORE SUBMITTING THE QUOTATIONS.

3 SPECIAL REQUIREMENTS ALL SPECIAL REQUIREMENTS, SPECIAL ACCESSORIES, INSTRUMENTATIONS LIKE WINDING RTDS, BEARING RTDS, DIAL THERMAMETERS, HOT AND COLD AIR RTDS/DIAL THERMAMETERS, FOUNDATION BOLTS REQUIREMENTS OF TERMINAL BOXES, PROVISION FOR MOUNTING VIBRATION PROBES, TACHO AND SIMILAR OTHER REQUIREMENT IF INDICATED AT TENDER STAGE WILL BE HELP FUL TO BUYER TO GET A CORRECT OFFER AND PRICE COMPARISION BRINGING ALL THE TENDERERS AT THE SAME FRAME/LEVEL.

8. EFFECT OF ATMOSPHERICE CONDITIONS:-

MOTOR MAY HAVE TO PERFORM IN VARIETY OF ATMOSPHERIC CONDITIONS DEPENDING UPON GEOGRAPHICAL CONDITIONS, TYPE OF PLANT, REGION, AND SEASON IN A YEAR.

CLEAN AND DUST FREE ATMOSPHERE IS EXCELLENT BUT THIS MAY BE AVAILABLE IN A CLEAN POWER HOUSE OR IN A CLOSED DOOR WORKSHOP, OR A VERY CLEAR DRY/DUST FREE REGION. SUCH ATMOSPHERE IS SELDOMNLY AVAILABLE.

ATMOSPHERE EITHER WILL BE HUMID/CONTAMINATED OPEN AIR SUSTABLE TO RAINS/WINDS ETC OR TOO DUSTY(LIKE IN A CEMENT PLANT) OF HAVING COAL PARTICLES(IN A COAL WASHERY/THERMAL POWER STATION OR COLLIARY ETC) OR CHEMICAL PLANT AND SIMILAR ATMOSPHERICE CONDITIONS, DEPENDING UPON THE DEGREE THE PROTECTION TO ENCLOSURE RANGING FROM IP44 TO IP 55 IS REQUIRED TO BE SELECTED AND SPECIFIED BY THE INDENTOR.

FOR SPECIAL CONDITIONS HAVING HAZARDOUS ATMOSPHERIC CONDITIONS LIKE IN REFINERY/ CHEMICAL/HEAVY HYDROGEN PROJECT/HEAVY WATER PROJECT/GAS PLANT ETC) INVOLVE SPECIAL CLASS OF PROTECTION AND WILL NEED MOTORS WITH ENCLOSURES WITH PRESSURISATION UNITS OF FLAME PROOF MOTORS. THESE TYPES HAVE DIFFERENT IMPLICATIONS AND THEREFORE CAREFUL SELECTION OF PROPER ENCLOSURE IS OF ATMOST IMPORTANCE. SUCH ATMOSPHERES ARE LIKELY TO BE SUSTABLE TO CATCHING FIRES AT HIGHER TEMPERATURES. AND THEREFORE THE BUYER IS REQUIRED TO SPECIFY THE TEMPERATURE CLASS WHILE INDICATING REQUIREMENT.

SUCH ATMOSPHERES ARE NORMALLY SPECIFIED AS GROUP C OR D OR E AND ZONE 1, 2 OR 3 . FOR ATMOSPHERES SUSTABLE TO EXTREME FIRE CATCHING CONDITIONS INVARIABLY FLAME PROOF SPECIAL MOTORS ARE TO BE USED.

THE INDIAN STANDARD 13408 INDICATES VARIOUS TEMPERATURE CLASSES WHICH INDICATE LIMITATIONS FOR MAX TEMPERATURE FOR ANY SURFACE OF THE MOTOR THESE ARE SPECIFIED AT TEMP CLASS T1, T2 , T3,T4, T5 AND T6 THE THEME IN THIS IS THAT THE SURFACE TEMPERATURE SHOULD IN NO CASE EXCEED THE LIMITS SPECIFIED IN ABOVE CLASSES SO AS TO PREVENT CHANCES OF FIRE BY INFLAMABLE GASES PRESENT IN THE VICINITY OF THE MOTOR FOR EACH TEMP CLASS VARIOUS LIMITS GIVEN ARE AS FOLLOWS:- TEMP CLASS T1..450 DEG C TEMP CLASS T2.300 DEG C TEMP CLASS T4.150 DEG C TEMP CLASS T5.120 DEG C AND TEMP CLASS T6.... 85 DEG C

CONT..PAGE 13/-

M/S HELP LINE(CONSULTING ENGINEERS) PAGE 13/-

9. NOISE AND VIBRATION OF MOTORS

VARIOUS STANDARDS ARE AVAILABLE WHICH IDENTIFY NOISE AND VIBRATIONS VALUES FOR MOTORS OF DIFFERENT RATINGS AT DIFFERENT SPEEDS. HOWEVER FOLLOWING ARE WORTH CONSIDERING WHILE INDENTING AN EQUIPMENT:-

A) NOISE:- NOW A DAYS NOISE POLLUTION HAS GAINED IMPORTANCE AND GENERALLY NOISE LEVELS OF THE ORDER OF 85 DBA OR LESS ARE BEING ACCEPTED BY WESTERN COUNTRIES PARTICULARLY USA/CANADA.

FOR SPECIAL APPLICATIONS LIKE FRIGATES/SUBMARINES NOIZSE LEVELS EVEN LESS THEN 70 dBA ARE REQUIRED FOR MG SETS/ALTERNATORS.

WHILE FOR 6P AND 4P MOTORS NOISE LEVELS ARE POSSIBLE TO ACHIEVE IN THESE LIMITS. FOR 2 POLE MOTORS DUE TO HIGH AIR TURBULANCE OF AIR AND HIGH PERIPHERIAL SPEEDS NOISE LEVELS OF THESE ORDER ARE DIFFICULT TO ACHIEVE. SOME REPUTED MANUFACTURES DEPLOY NOISE REDUCERS AT NDE SIDE OF THE MOTORS TO REDUCE NOISE LEVELS.

IN WESTERN COUNTRIES PARTICULARLY IN USA FOR REDUCTION IN NOISE LEVELS, ALTERNATORS AND LARGE MOTORS ARE HOUSED IN DOUBLE LAYER BOXES AND INTER LAYER IS PROVIDED WITH NOISE ABSORBERS..

PRIMARILY IT IS VENTILATION AND AIR CIRCULATION CIRCUIT WHICH IS RESPONSIBLE AND THERE FORE NEEDS TO BE CONSIDERED BY THE VENDOR WHILE QUOTING A MOTOR./ELECTRICAL EQUIPMENT.

B) VIBRATION:-

IN TEST FIELD /TEST BED IT IS A COMMON PRACTICE TO MEASURE VIBRATION BOTH IN VELOCITY MODE AND DISPLACEMENT MODE. I.E. VELOCITY ..IN MM/SEC DISPLACEMENT.IN MICRONS THESE MEASUREMENTS ARE DONE AT PLACES LIKE PEDESTAL/BEARING AT MOTOR BASE.(ONLY FOR REFERENCE PURPOSE) AT DRIVE END AND NON DRIVE END OF THE MOTOR.

VIBRATIONS ARE MEASURED AT VERTICAL, HORIZONTAL AND AXIAL DIRECTIONS. VERTICAL VALUES .INDICATES HEALTHYNESS / CORRECTNESS OF MOUNTING PADS/FOUNDATION AXIAL VALUES INDICATES ABOUT PROPER ALIGNMENT

OF EQUIPMENT WRT SLAVE(DRIVING UNIT) OR WITH RESPECT TO MACHINE ITSELF

HORIZONTAL VALUES ..INDICATES WHETHER ROTOR OF THE MACHINE HAS BEEN PROPERLY BALANCED OR NOT

VIBRATION VALUES BOTH IN DISPLACEMENT AND VELOCITY MODE IN ALL I.E. VERTICAL, HORIZONTAL AND AXIAL AXIS ARE IMPORTANT.BUT VELOCITY MODE IS MORE IMPORTANT FROM POINT OF VIOEW OF FOUNDATION DESIGN AS IN FOUNDATION DESIGN CALCULATIONS MM/SEC(VELOCITY MEASUREMENT) ARE CONSIDERED FOR ANALYSING DAMPED VIBRATIONS AND NATURAL FREQUENCY OF VIBRATION OF THE WHOLE SYSTEM WHEN EQUIPMENT AND SYSTEMARE CONSIDERED COMBINED TOGETHER(REF FOUNDATION DESIGN HAND BOOK BY VIDYANATHAN AND SOMAYUJULU)

RELEVENT IS/IEC STANDARDS GIVES GUIDE LINES FOR LIMITING VALUES FOR VARIOUS SPEED/RATINGS.

CONTPAGE 14/-


10. MOTOR BEARINGS :-

THIS IS A COMPONENT WHICH ALLOWS ROTOR OF THE MOTOR TO REST ON THE STATOR THROUGH END SHIELD/BEARING PEDESTALS AND WHILE RUNNING FACILIATES FREE ROTATION OF ROTOR FOR DELIVERY OF REQUIRED TORQUE THROUGH SHAFT EXTENSION

A MOTOR OR A GENERATOR CAN HAVE TWO TYPES OF BEARING SUPPORTS:-

A) BALL AND ROLLER BEARINGS WHICH ARE HOUSED IN BEARING INNER RACE AND OUTER RACE. THE BEARING OUTER RACE IS FITTED IN BEARING HOUSING WHICH IF CLAMPED TO THE STATOR THROUGH END SHIELDS. WHILE INNER RACE IS SHRINKED ON THE ROTOR SHAFT. IT IS THIS INNER RACE WHICH ROTATES WITH THE SHAFT. THE BALL/ROLLER BEARING FACILIATE EASY/FRICTION FREE ROTATION THROUGH CONTINUOUS CONTACT BETWEEN INNER RACE AND OUTER RACE.

A COMBINATION OF BALL AND ROLLER BEARING IS FITTED ON DRIVING END SIDE OF THE SHAFT(OR MOTOR) BECAUSE THE SHAFT EXTENSION IS SUBJECTED TO THE LOAD. THE NON DRIVING END SIDE IS FITTED WITH BALL BEARINGS.

THESE BEARINGS ARE CALLED ANTI FRICTION GREASE LUBRICATED BEARINGS. SUCH BEARINGS HAVE LIMITED LIFE IN TERMS OF HOURS OF RUN. BEARING LIFE IS GENERALLY SPECIFIED BY THE SUPPLIER OF MOTORS/GENERATORS AND SHOULD BE ASKED BY THE BUYER WHILE INDENTING FOR THE EQUIPMENT.

IN GENERAL BALL BEARINGS CAN TAKE AXIAL THRUST(BUT THERE IS NO OR VERY LITTLE AXIAL PLAY) WHILE ROLLER BEARINGS CAN HAVE AXIAL PLAY(AND THERE FORE AXIAL THRUST IS NOT ALLOWED ON MOTORS PROVIDED WITH ROLLER BEARINGS) THIS IS THE REASON WHY DRIVE END SIDE BEARING HAS COMBINATION OF BALL AND ROLLER BEARING SO AS TO TAKE SOME AXIAL THRUST DURING LOADING

B) OTHER TYPE IS END SHIELD OR PEDESTAL MOUNTED SLEEVE BEARINGS THESE CONSIST OF A ROUND BUSH HAVING HIGH PRECISION BABBITING MATERIAL DEPOSITED ON INSIDE OF THE SLEEVE BY HIGH SPEED CENTRIFUGAL PROCESS. AND LATER FINE MACHINING TO ACHIEVE REQUIRED INNER DIA OF THE SLEEVE. THE BABBITING MATERIAL HAS PORSITY TO RETAIN LUBRICATING OIL. SLEEVE BEARINGS WORK ON THE PRINCIPLE THAT THE LUBRICATING OIL (GENERALLY ISO VG 46 OR 48 OR 62) WHEN INTRODUCED INTO THE SLEEVE AT A PRESSURE (MAY BE 0.2 TO 0.5 BAR) WILL FORM A THIN FILM BETWEEN THE BABBIT MATERIAL OF THE BUSH AND THE SHAFT. THE FILM THICKNESS IS SUCH THAT IT CAN SUSTAIN THE LOAD OF THE ROTATING SHAFT(INCLUDING ROTOR). THE OIL IN THE SLEEVE BEARING IS FORCED THROUGH FOL SYSTEM WHICH IS SUPPLIED ALONGWITH THE MOTOR/GENERATOR .

THESE TYPE OF BEARING ARRANGEMENT THEORITICALLY HAS UNLIMITED LIFE AS LONG AS OIL FLOW RATE AND PRESSURES ARE MAINTAINED.

HOWEVER DUE TO PROLONGED OPERATION, BABBIT MATERIAL MAY WORN OUT AND THE BEARING SLEEVES MAY HAVE TO BE REPLACED IF VIBRATIONS ARE GOING BEYON PERMISSIBLE LIMITS. . BEFORE STARTING THE MOTOR OR GENERATOR WITH SLEEVE BEARING ARRANGEMENT, IT SHOULD BE ENSURED THAT REQUIRED QUANTITY OF OIL FLOW AND PRESURE IS MAINTAINED.

THE CAUSE OF WEARING OUT SUCH SLEEVE BEARINGS IS PRIMARILY DUE TO CANTAMINATED OIL/LESS VISCOUS OIL OR TOO MANY STARTS AND STOPS. WHEN THE MOTOR IS AT REST, THE SHAFT RESTS ON THE BABBIT MATERIAL. THOUGH OIL QUANTITY AND PRESSURE IS MAINTAINED, THE PORTION AT WHICH SHAFT IS AT REST ON THE SLEEVE, THER IS VERY LITTLE OIL FILM OR NO FILM. IT IS ONLY AT T=DELTA T THAT OIL RUSHES IN THIS PORTION INITIATING THE FILM. LIKE THIS THERE COULD BE SOME EROSION OF BABIT MATERIAL. SIMILARLY DUE TO CONTAMINATED OIL, LOW VISCOSITY THERE IS IN SUFFICIENT FILM FORMATION OF SKRETCH MARKS RESULTING EROSION OF BABIT MATERIAL RESULTING WEARING OUT OF SLEEVES NEEDING REPLACEMENTS.

CONT..PAGE 15/-


IN GENERAL FOR 2 P MOTORS AND MACHINES REQUIRING TO TRANSMIT LARGE TORQUES IT IS PREFERABLE TO HAVE MOTORS WITH SLEEVE BEARINGS AS THEIR MAINTENANCE AND OPERATION IS EASY.

SLEEVE BEARINGS CAN NOT TAKE ANY AXIAL THRUST AND WILL HAVE AXIAL FLOAT AS SHAFT IS FREE FOR AXIAL MOVEMENT(WITHIN BUSH LIMITS). THEREFORE IN SUCH MACHINES , MAGNETIC IS VERY IMPORTANT TO PREVENT EXCESSIVE AXIAL FLOAT. MANY TIMES DESIGNERS RECOMMEND TO CONTROL AXIAL FLOAT BY LIMITING FLOAT IN THE COUPLING. TYPICALLY FOR PEDESTAL MOUNTED ALTERNATORS MAX ALLOWED AXIAL FLOAT IS +/-- 1.5 MM TO BE CONTROLLED IN THE COUPLINGS.

C) FOR VERTICAL MOTORS DRIVE END SIDE(BOTTOM) HAS ROLLER BEARINGS AND NON DRIVE END SIDE HAS ANGULAR CONTACT ROLLER BEARINGS. IT IS RECOMMENDED THAT PUMP THRUST SHOULD NOT BE TRANSFERRED ON THE MOTOR BEARING SINCE AT DRIVE END SIDE THE MOTORS ARE PROVIDED WITH ROLLER BEARINGS. GENERALLY PUMPS SHOULD BE SO SELECTED THAT THE BEARINGS OF THE PUMP ARE ABLE TO TAKE ANY AXIAL THRUST GENERATED DURING LOADING OF THE PUMP.

12 PERFORMANCE EVALUATION(AT WORKS):-

ALL THE MANUFACTURERS HAVE SEPARATE TEST BED FACILITY WHERE MOTORS CAN BE SUBJECTED TO FIELD TRIALS.

A1 MOTORS OF EACH DESIGN ARE SUBJECTED TO TYPE TESTS(INCLUDING ROUTINE TESTS) LIST OF TESTS ARE INDICATED IN VARIOUS SATANDARDS FOR SUCH TESTS. FOR WHICH VARIOUS STANDARDS ARE AVAILABLE. SINCE DETAILS OF TESTS ARE ELEBORATED IN THE RELEVENT STANDARTDS , THEY ARE NOT LISTED HERE AND FOCUS ONKEY ISSUES.

A2 MOTORS OF REPEAT DESIGN ARE SUBJECTED ONLY FOR ROUTINE TESTS.

A3 IN CASE OF FLAME PROOF MOTORS , SINCE EACH MOTOR IS LIKELY TO BE SUBJECTED TO HAZARDOUS ATMOSPHERE, EACH MOTOR IS REQUIRED TO BE TESTED AT CMRI/DHANBAD FOR ASCERTAINING ITS CORRECTNESS OF ENCLOSUREFR FLAME PROOF FAIL SAFE OPERATIONS. IT MAY BE NOTES THAT AT CMRI DHANBAD ONLY PROTECTION TO ENCLOSURE IS ASCERTAINED AND BALANCE TESTS ARE TO BE CARRIED OUT AT MANUFACTURERS WORKS.

A4 TYPE TESTS INCLUDE A SERIES OF TESTS INCLUDING HEAT RUN TEST FOR EVALUATION OF TEMPERATURE RISE FOR MOTOR WINDING AND OTHER PARTS. BESIDE THIS MANUFACTURER ALSO USES THIS DATA OF TESTS FOR EVALUATION OF EFFICIENCY.

METHODS OF PERFORMANCE EVALUATION DURING TEST BED FIELD TRIALS:-

A) CALCULATION OF TEMP RISE AND LOSSES:-

THERE IS NO DIRECT METHOD OF MEASUREMENT OF OUTPUT OF THE MOTOR. THOUGH IN LABORATORIES STRAIN GAUGES ARE FIXED ON THE SHAFT AND TORQUE CAN BE MEASURED TO ASCERTAIN OUTPUT BEING DELIVERED BY THE MOTOR DURING VARIOUS LOAD, THIS CAN ONLY BE A LOABORATOR MODEL AND FOR A MANUFACTURER, NEEDING TO PRODUCE 400 TO 600 MOTORS OF DIFFERENT DESIGNS( ROUGHLY 150 TO 200 ON AN AVERAGE) IT IS NEITHER POSSIBLE NOR PRACTICAL TO TYPE TEST MOTORS ON LINES OF LABORATOR Y MODELS.

CONTPAGE 16/-


THEREFORE, A MUCH SIMPLER AND ASERTIVE METHOD IS TO ASSESS INPUT POWERSUPPLY AND FEED TO THE MOTOR. THE METHOD INVOLVES :-

A) ASSESSMENT OF TEMP RISE AND FULL LOAD LOSSES.1) ASSESSMENT OF INPUT POWER BY DIVIDING THE RATED OUT PUT RATING BY THE

GUARANTEED EFFICIENCY(OR THE DESIGNED EFFICIENCY) 2) MOTOR IS RUN AT ABOVE INPUT POWER SUPPLY AT RATED VOLTAGE AND CURRENT

DRAWN BY THE MOTOR IS MEASURED. THE CURRENT VALUE SHOULD BE NEAR TO THEDESIGNED FULL LOAD AMPS. IF THE MOTOR IS DRAWING MORE CURRENT(WITHINPERMISSIBLE VARIATION) IT SHOWS THAT THE MOTOR MAY HAVE POWER FACTOR LOWER THEN THE DESIGNED OR THE MOTOR MAY HAVE MORE LOSSES. IN SUCH CASES DESIGNER MAY HAVE TO BE REFERRED THE CASE.

3) INPUT KW, KVA, POWER FACTOR, SPEED, BEARING TEMP, STATOR FRAME TEMPERATUREAND OTHER PARAMETERS ARE REQUIRED TO BE MEASURED WITH TIME INTERVAL TILL THE MOTOR HAS REACHED POSITION OF THERMAL EQUILIBRIUM(I.E TEMP RISE HAS STABILISED)

4) MOTOR IS PUT FOR SHUT DOWN AND HOT WINDING TEMPERATURE IS MEASURED.GENERALLY IT TAKES SOME TIME FOR THE MOTOR TO COME TO REST AFTERWHICHONLY HOT WINDING RESISTANCE TO BE MEASURED WITH THE BRIDGE (THERE ARE SEPARATE STANDARDS FOR METHOD OF MEASUREMENT AND CORRECTION FACTO5RSTO BE EMPLIED FOR ARRIVING HOT WINDING TEMPERATURE AT THE INSTANT OF SHUT DOWN). THIS WILL CONFIRMATION OF SUITABILITY OF MOTOR FOR THE INDENTEDTEMPERATURE RISE.

C) ASSESSMENT OF EFFICIENCY:-

FORASSESSMENT OF EFFICIENCY WE NEED NO LOAD LOASSES(COMPRISING IRON LOSS,FRICTION AND WINDAGE LOSS ) AND FULL LOAD LOSSES, STRAY LOAD LOSSES.

1) NO LOAD LOSS ASSESSMENT:-@ MOTOR IS RUN AT NO LOAD AT VARIOUS VOLTAGES(GENERALLY FROM 120% RATEDVOLTAGE TO 25% RATED VOLTAGE) AND INPUT KW, AND CURRENT IS NOTED. A GRAPH IS DRAWN BETWEEN INPUT KW AND VOLTAGE. THE GRAPH IS INTERPOLATED BELOW 25% RATED VOLTAGE SUCH THAT IT INTERSECTES Y AXIS. THE PORTION XX SHOWN WILL BEFRICTION AND WINDAGE LOSS. AND BALANCE WILL BE IRON LOSS+NO LOAD COPPER LOSS.

NO LOAD LOSS CURVE

IN PUT KW

EXTRAPOLATED PORTIONCURVE DRAWN BASED ON TEST

XX25% 50% 75% 100% 120% VOLTAGE

2) FULL LOAD LOSS IS KNOWN FROM TEMPERATURE RISE TEST CARRIEDAS PER PARA A ABOVE

3) TOTAL LOSSES = NO LOAD LOSS+ FULL LOAD LOSS+ STRAY LOAD LOSS 4) EFFICIENCY= (INPUT-TOTAL LOSSES)/INPUTX100 = % EFFY.

CONT PAGE 17/-


4 MEASUREMENT OF LOCKED ROTOR TORQUEFOR CARRYING OUT THIS TEST, THE MOTOR IS CLAMPED WITH THE BED FIRMELY AND SHAFT IS ALSO PROPERLY LOCKED SO AS TO PREVENT ITS ROTATION.CURRENT IS SUPPLIED AT 100%, 150% AND 200% OF RATED CURRENT AND VOLTAGE IS MEASURED AT EACH CURRENT VALUEINPUT POWER IS ALSO MEASURED.FROM ABOVE DATA, AS PER JEC 37 LOCKED ROTOR TORQUE AND CURRENTS AREEVALUATED.

5 ASSESSMENT OF OTHER PARAMETERS:- OTHER PARAMETERS IMPORTANT FROM PERFORMANCE POINT OF VIEW ARE:-

VIBRATION . LIMITES SHALL BE IN LINE WITH GUIDE LINES GIVEN IN RELEVENT STANDARDS FOR RATINGS, SPEEDS ANDTYPE OF MOUNTING.

NOISE . .NOISE LEVELS ALSO VARY FOR DIFFERENT MACHINES, ITS VALUES WILL DEPEND ON SIZE, TYPE, SPEED AND OTHER

PARAMETERS FOR WHICH RELEVENT STANDARDS CAN BEREFERRED.

SHAFT . .IN ANY MOTOR THEORITICALLY SHAFT VOLTAGE SHOULD VOLTAGE BE ZERO. HOWEVER IT IS NOT PRACTICAL AND THERE WILL

BE SOME RESIDUAL VOLTAGE . HOWEVER EFFORTS SHOULD BE TO KEEP IT MINIMAL. AND TAKE PREVENTATIVE BYINSULATING ONE SIDE BEARING TO AVOID ANY CIRCULATINGCURRENT (WHICH WILL RESULT IN ITCHING OF BEARING)

IR, PI, HV AND TAN DELTA TESTS:- THOUGH IN ALL STAGES OF MANUFACTURE, STATORS, WOUND ROTORS ARESUBJECTED TO STAGE INSPECTION, WHICH INCLUDE INTER TURN TEST AND HIGH VOLTAGETEST, IT IS CUSTOMARY TO CONDUCT THESE TESTS AFTER ALL THE PERFORMANCE TRIALSARE COMPLETED.

1) BEFORE CONDUCTING H.V. TEST IT IS ESSENTIAL TO CARRY OUT IR TEST FOR VARIOUSWINDINGS. AND IF IR VALUE IS LOW IT IS NECESSARY TO INVEASTIGATE CAUSE OF LOWIR VALUE.

IR VALUE TEST IS TO BE DONE WITH SUITABLE MEGGERING INSTRUMENTS WHICH AREAVAILABLE IN VARIOUS VOLTAGES OF 500 VOLTS TO 5KV. DEPENDING UPON THEVOLTAGE CLASS OF MACHINE (LT, 3.3KV, 6.6KV, OR 11 KV) TEST VOLTAGE FOR MEGGERING SHOULD BE SELECTED.

2) PI VALUE TEST:

THIS IS POLARISATION INDEX TEST AND INVOLVES MEASUREMENT OF IR VALUE BETWEEN 1 MINUTE AND 10 MINUTE INTERVAL THE UNDERLYING PRINCIPLE IS THATEACH WINDING WITH CONNECTING CABLES, TERMINAL BUSHING ETC IS A SERIES OFHIGHE RESISTANCES AND CAPACITANCES. TYPICALLY IN ELECTRICAL TERMS IT CAN BE SHOWN AS FOLLOWS:-

R1 R2 R3

C1 C2 C3 WINDING CABLES BUSHING ETC.

CONT..18/- HELP LINE(CONSULTING ENGINEERS) PAGE 18/-

WING

O BE 2.0 AS PER EE 43-1974. THIS CAN BE CONSIDERED AS GENERAL GUIDE LINES ONLY.

UGS FOR APPROX 100 TO 150 MM WAS EMOVED, THE IR VALUE SHOWED IMPROVEMENTS.

HEREFORE HIGH INITIAL IR VALUES RECORDED AT 1 IN TEST IT SELF MAY BE VERY HIGH.

R CONSULTING DESIGNERS/EXPERTS IT CAN BE CONSIDERED TO GO OR HV TESTS .

6KV. AND IS A MEASURE F THE LONGIVITY OF THE INSULATION DURING PROLONGED USE.

EAN THAT WINDING

STUDY OF OTORS. ENERGY AUDITORS MAY FIND THE TEST USEFUL DURING RLA STUDY

RALLY HAVE BEEN FOUND TO CONSIDER TAN ELTA VALUE RANGING FROM 0.02 TO 0.035

T EXCEED THE DEPARTMENT SPECIFIED ALUES LAID DOWN BY THE MANUFACTURER.

13

EY ARE UNNING AT PART LOADS OR HAVE SERVED FOR LONG PERIOD HAS GAINED IMPORTANCE:

D OPERATION ARE CARRIED OUT ROPERLY FOR ANY RISK OF FAILURE OR POOR PERFORMANCE.

CONT PAGE 19/-

WHEN A VOLTAGE IS APPLIED, INITIALLY DUE TO CAPACITANCE IN THE CIRCUIT CHARGING CURRENT WILL FLOW THUS SHOWING LOW IR VALUE AS THE TIME PASSES THE CAPACITORS WILL GET CHARGED RESISTING THE FLOW OF CURRENT SHOINCREASING RESISTANCE VALUE . IN A DRY ATMOSPHERE, RECOMMENDED VALUES OF RATIO OF IR BETWEEN 10 MINUTES AND 1 MINUTE ARE RECOMMENDED TIE

IT MAY BE NOTED THAT EVEN SURROUNDING VOLUME OF AIR IS ALSO GETTING ENERGISED. AND IF DUST , MOISTURE ARE AVAILABLE IN THE VICINITY OF CABLES OR BUSHING THEY MAY GIVE LOW RESISTANCE PATH FOR DISCHARGING CURRENT RESULTING NO SUBSTANTIAL IMPROVEMENT IN THE RATIO. PRACTILE FIELD TESTS HAVE SHOWN THAT GLASS BRADED SILICON CABLES USED FOR CONNECTING STATOR LEADS TO TERMINAL BUSHINGS , DUE TO GLASS BRADING USED TO GIVE NO SUBSTANTIAL IMPROVEMENT IN IR VALUE, BUT WHEN GLASS BRADING AT THE CABLE LR

MORE EVER, FOR PI VALUE THERE IS NO WRITTEN STANDARD AND VARIOUS WRITE UPS HAVE NOT BEEN UPDATED TAKING INTO ACCOUNT THE DEVELOPMENTS TAKEN IN THE FIELD OF VARNISHES/INSULATIONS NOW BEING EMPLOYED FOR WINDING AND OTHER LIVE PARTS OF THE MOTORS/EQUIPMENT. TM

AS SUCH PARTICULARLY DURING RAINY SEASON WHEN ATMOSPHERE IS HUMID, IN CASE RATIO OF IR VALUE BETWEEN 10 MIN TO 1 MIN IS LOW, BUT IF INITIAL IR VALUE(1 MIN VALUE) IS VERY HIGH , AFTEF

SIGNIFICANCE OF TAN DELTA TEST:- THIS TEST IS PERFORMED TO ASCERTAIN THE DIELECTRIC STRENGTH OF INSULATION. THIS TESTS IF GENERALLY PERFORMED FOR MACHINES OF 11 KV OF 6.O

THOUGH THERE IS NO STANDARD LAID DOWN FOR THIS TEST THE RECORDS OF THIS TEST CAN BE KEPT FOR THE REFERENCE PURPOSE. DURING SERVICE OF OPERATION (COULD BE 2 YEARS OR 3 YEARS) TAND DELTA MEASUREMENTS AT SITE SHOULD NOT SHOW LARGE DETORIATION. IF RECORDS SHOW DETORIATION THEN THIS WILL MINSULATION IS TO BE RESTRENGTHENED TO IMPROVE LIFE OF MOTOR.THIS TEST IS USEFUL FOR THE PURPOSE OF RESUDAL LIFE ACCEPTANCYM

THE TAND DELTA VALUE LIMITS MAY VARY FROM MANUFACTURER TO MANUFACTURER HOWEVER REPUTED MANUFACTURERS GENED

THE TEST INVOLVES SUPPLY OF PART VOLTAGES RANGING FROM 20% TO 110% OF RATED VOLTAGE ACROSS EACH PAHSE OF THE STATOR WINDING FOR SHORT DURATION AND RECORDING TAN DELTA VALUES AND CORRESPONDING CAPACITANCE VALUES AT EACH VOLTAGE. TAN DELTA VALUES SHOULD NOV

PERFORMANCE ASSESSMENT OF MOTORS IN OPERATION:- SINCE WORLD OVER FOCUS IS ON ENERGY CONSERVATION AND SAVING ON ENERGY, PERFORMANCE ASSESSMENT OF MOTORS DURING OPERATIONS PARTICULARLY WHEN THR

PERFORAMNCE ASSESSMENT OF SERVICED OR REWOUND MOTORS IS IMPORTANT SINCE DURING SERVICE/REWINDING THERE COULD BE MODIFICATIONS OR CHANGES. EVEN IF CHANGES ARE NOT CARRIED, IT IS IMPORTANT TO KNOW WHETHER ALL THE REQUIREP

HELP LINE(CONSULTING ENGINEERS) PAGEE 19/-

AY BE REQUIRED TO BECARRIED OUT FROM THE AVAILABLE OR BORROWED STRUMENTS.

A)ASURE THE

PUT POWER BY PORTABLE POWER ANALYSER, OR 2/3 PHASE POWER METER.

SHEET OR RATING HIS DATA RATED INPUT CAN BE CALCULATED AS

ATED INPUT POWER = RATED OUTPUT/EFFICIENCY

HE PERCENTAGE LOADING = ACTUAL INPUT POWER/RATED INPUT POWER

B)

FOUND OUT BY MEASURING INPUT CURRENT AND DIVIDING SAME BY

OF THE MOTOR MAY GO SUBSTANTIALLY OWN AND RESULTS MAY NOT BE ACCURATE.

C)IBLE, THEN % LOADING

D. LOADING

IT MAY BE NOTED THAT AT SITE, ALL THE NECESSARY INSTRUMENTATION, EQUIPMENT(WHICH ARE GENERALLY AVAILABLE AT SUPLIERS WORK) MAY NOT BE AVAILABLE AND THEREFORE ASSESSMENT MIN

ASSESSMENT BY INPUT DATA:- ASSUMING THE MOTOR IS CONNECTED TO THE LOAD AND IN OPERATION, MEIN

RATED POWER AND EFFICIENCY CAN BE NOTED FROM MOTOR DATAPLATE . BASED ON TFOLLOWS:- R

T

ASSESSMENT BY INPUT CURRENT SOME TIMES POWER ANALYSER MAY NOT BE AVAILABLE AT SITE. THEN MOTOR LOADING CAN BE RATED CURRENT. HOWEVER THIS METHOD IS USEFUL FOR LOADING UPTO 75% OF FULL LOAD CURRENT SINCE BELOW THIS LOADING POWER FACTORD

ASSESSMENT BY SPEED:- SOME TIMES EVEN CURRENT MEASUREMENT IS NOT POSSCAN BE EVALUATED BASED ON ACTUAL MOTOR SPEE% = (SYN SPEED-MEASURED SPEED (SYN SPEED-RATED SPEED) X (VR/V)SQ

WHERE VR = RATED VOLTAGE, V= ACTUAL VOLTAGE

5. FOR CORRECTNESS ACTUAL SUPPLIER TEST DATA MAY BE EFERRED.

14

FULL LOADING OF MOTORS IS VERY IMPORTANT FROM NERGY CONSERVATION POINT OF VIEW.

EQUIPMENT SUPPLIER ETC AND MAY RESULTS IN POOR OWER FACTOR AND LOW EFFICIENCY.

TIONS. AND FEW OF COMPRESSORS CAN E HUT DOWN BY SUITABLE ON OFF CONTROL SYSTEM.

RES MENTIONED ABOVE AND OTHER MEANS OF COST FFECTIVE ENERGY SAVING MEASURES.

CONT20/-

ACCURACY OF THIS METHOD HOWEVER IS LIMITED AS THE SLIPS INDICATED ON THE RATING PLATE MAY BE ROUNDED OFF TO NEAREST MULTIPLE OFR

MOTORS AND ENERGY CONSERVATION:- MOST OF THE INDUSTRIES USE LT OR HT MOTORS FOR CONVERTING ELECTRICAL POWER INTO USEFUL MECHANICAL WORK AND ALL THE MOTORS WORK WITH POWER FACTORS RANGING BETWEEN 0.86 TO 0.75. AND THEREFOREE

UNDERLOADING WHICH COULD BE RESULT OF MARGINS IN DESIGNS, SAFETY FACTOR CONSIDERED BY THE USER/MECHANICALP

IN GENERAL, IF MOTORS ARE OPERATING WITH LOADING ABOVE 60% IT MAY NOT BE NECESSARY TO CHANGE THE MOTORS. HOWEVER FOR APPLICATIONS LIKE PUMPS WHERE WITH SUITABLE PIPING MODIFICATIONS, CLUBBING OF PUMPS IS POSSIBLE, REDUCED FLOW RATES CAN BE ACHIEVED BY SHUTING DOWN SOME PUMPS . SIMILAR IN CASE OF FANS IF REDUCED QUANTITY OF GAS OR AIR IS REQUIRED IT IS PREFERABLE TO USE VVF CONTROL IN PLACE OF PARTIAL CLOSING OF DAMPERS. IN CASE OF COMPRESSORS ALSO THE COM,PTRESSOR WHICH IS OF LOWEST CAPACITY SHOUL BE ALLOWED TO GO FOR LOAD VARIAB

CHANGES IN MOTORS ARE ATTRACTIVE WHERE EVER THERE IS VIDE DIFFERENCE IN EXISTING MOTOR RATING AND REAL REQUIRED LOAD. IN GENERAL REPLACEMENT SHOULD BE CONSIDERED AFTER ADOPTING ALL POSSIBLE MEASUE


ION, DISTRIBUTION, LFERAGE AND OTHER INTERFACE ELECTRICAL EQUIPMENT/CONTROLS.

SUMED IN RESIDENTIAL, 5 TO 10 % IN GRICULTURE AND REMAINING IN MISC CONSUMPTIONS

ATION IN THESE AREAS CAN PLAY VITAL ENERGY SAVING ROLE IF NERGY IS PROPERLY USED.

ES, IT WILL BE PRUDENT TO OPTIMISE USE OF ENERGY FOR BENEFIT OF SOCIETY AT LARGE BY;

OPERATING AT POOR POWER FACTOR AND EFFICIENCY RESULTING ENERGY LOSSES.

2)

E OF FANS/PUMPS WHICH AS A OLLOW AFFINITY LAW IN WHICH CASE

GY IN MOTOR. OFF OURSE PANEL EFFICEIENCY WILL HAVE TO BE TAKEN INTO ACCOUNT.

EQUIRED NET POSITIVE SUCTION HEAD REQUIRED TO MAINTAIN REQUIRED LOW RATE.

15 TRAN

TH DISTURBED ALIGNMENT WILL ATTRACT REWORK, ELAYS AND COST OVER RUNS.

LD BE PROPERLY SECURED AND PROTECTED BEFORE CARRYING OUT ACKING WORK.

MEDIUM MOTORS SHAFT EXTENSION

O PREVENT ANY DAMAGE DURING UNLOADING/OPENING F PACKING BOX AND ERECTION .

CONTPAGE 21/-

CONSERVATION OF ENERGY IN MOTORS: - WORLD OVER POWER PLANTS OPERATE WITH EFFICIENCIES RANGING FROM 28 TO 35% WITH RESPECT TO SIZE, AGE AND UTILITY FACTOR. OUT OF TOTAL POWER PRODUCED ONLY 50% IS GETTING CONVERTED INTO USEFUL OUT, REST GETTING WASTED IN TRANSMISSPI

OUT OF TOTAL POWER GENERATED (IN INDIAN CONTEST), 49% IS CONSUMED IN INDUSTRY, 22 % IS CONSUMED IN TRANSPORT SECTOR, and 10% IS CONA

THUS MAJOR JUNK OF ENERGY IS CONSUMED IN INDUSTRY AND TRANSPORT AND AGRICULTURAL SECTOR. ENERGY CONSERVE

CONSIDERING LIMITED EXHAUSTING NON RENEWABEL RESOURC

1) SELECTING MOTOR RATINGS NEARER TO DUTY POINT USING RATING NEARER TO DUTY POINT RATING. AN OVER SIZED MOTOR OPERATING AT PARTIAL LOADS WILL BE

USING MOTORS WITH VARIABLE SPEED CONTROLS.THESE REQUIRE DEPLOYING VARIABLE VOLTAGE VARIABLE FREQUENCY CONTROL PANELS. THIS IS MORE USEFULE IN CASSYSTEM FQ = Kx N HEAD = K X (N) SQ POWER = K (N)3 OR = Kx (Q)3 THUS TO REDUCE THE FLOW IF SPEED IS REDUCED BY 20% KW POWER REQUIREMENT WILL REDUCE BY 40% THEREBY SAVING ON LOT OF ENERC

HOWEVER PUMP SPPEDS CAN ONLY BE REDUCED TO SOME EXTENT. IT IS NOT ADVISABLE TO REDUCE PUMP SPEED BEYOND 75% OF ITS FULL SPEED, AS THE PUMPS MAY NOT GENERATE RF

SPORTATION OF MOTORS PACKING AND TRANSPORTATION OF EQUIPMENT PLAYS A VITAL ROLE IN SAFE RECEIPT OF TESTED AND FINISHED MOTOR OR GENERATOR TO ITS DISTINATION. A NICELY TESTED EQUIPMENT REACHING SITE WID

THE VITAL PARTS LIKE SHAFT EXTENSION WHICH WILL BE COUPLED TO THE DRIVEN EQUIPMENT THROUGH COUPLING HAS TO BE DENT FREE FOR PROPER FITTING OF COUPLING. SIMILARLY THE INSTRUMENTATION PART LIKE, DIAL THERMAMETERS, BEARING TEMPERATURE DETECTORS, AND OTHER INSTRUMENTS FITTED ON THE EQUIPMENT SHOUP

FOR PROTECTION OF SHAFT- FOR SMALL AND GUARDS ARE PROVIDED BY THE MANUFACTURERS. WHERE EVER MOTORS ARE PROVIDED WITH SLEEVE BEARINGS, IT IS CUSTOMERY TO PROVIDE LOCKING ARRANGEMENT FOR THE SHAFT TO PREVENT MOVEMENT OF ROTOR DURING TRANSIT. THIS IS REQUIRED TO PREVENT ANY DAMAGE TO THE SLEEVE BEARING PROVIDED IN THE GENERATOR/MOTOR. IN THIS CASE ALSO PROPER PROTECTION TO THE SHAFT EXTENSION IS REQUIRED TO

HELP LINE(CONSULTING ENGINEERS) PAGE 21

STELAGS WILL PREVENT INGRESS OF WATER /MOISTURE AND PROTECTION FROM RAINS.

SION WILL BE REQUIRED FROM RAILWAY AND SEBS FOR RANSPORTATION.

NVOLVES

INGRESS OF WATER DUE TO SEA WAVES WHEN PACKING

ND ANTI TERMITE TREATMENT IS TO BEIVEN TO THE PACKING FOR GERMS PROTECTION.

RIFICATION OF EQUIPMENT AND THEREFORE PROVISION FOR PEEP WINDOW IS SSENTIAL.

16 STO

TO EXPECT THAT THE ENCLOSED ACHINE HAS BEEN RECEIVED WITHOUT ANY DAMAGE.

EOTHING IS LOSE OR DETACHED DUE TO VIBRATION OR INTERFERENCE DURING TRANSIT.

E COVERED SPACE SHOULD NOT BE SUBJECTED TOARGE TEMPERATURE VARIATION.

ING COVERS/EXTENSIONUARDS SHOULD BE USED TO PROTECT THE SHAFT EXTENSION.

F ACIDS/ALKILIES, CHEMICALS DRUMS/TANKS SHOULD BE VOIDED NEAR THE MACHINE.

CONT..PAGE 22/-

PACKING OF EQUIPMENT IN THICK POLYTHENE SHEETS AND KEEPING SILICA CRYB

HEIGHT OF THE PACKING BOX IS VERY IMPORTANT FROM TRANSPORATION POINT OF VIEWIN INDIAN CONTEST, THE CROSS BAR HEIGHT AT RAILWAY CROSSING IS AROUND 16 FEETAND 3 INCHES. SIMILARLY STATE SEBS SUB TRANSMISSION LINES (INCLUDING SAG) HASLOWEST HEIGHT OF 17FEET AND 3 INCHES. THEREFORE WHEN LOADED ON A CARRIER,IF POSSIBLE, THE HEIGHT SHOULD BE LIMITED TO ABOVE SPECIFIED LIMITS. OTHERWISESPECIAL PERMIST

SEA WORTHY PACKING IS MANDOTARY IN CASE OF EXPORT JOBS WHICH IBUTT-JOINTS IN EACH WOODEN SLEEVE AS SHOWN BELOW. THIS TYPE OF JOINTWILL REDUCE CHANCES OFBOX IS ON BOARD OF SHIP.

IN ADDITION TO SEA WORTHY PACKING, BEFORE TAKING UP EQUIPMENT FOR PACKING, ITHAS TO BE PACKED WITH THICK POLYPACKING AG

NOW A DAYS AT PORTS, CUSTOM AUTHORITIES WANT A PEEP WINDOW IN THE BOX FORPHYSICAL VEE

RAGE OF EQUIPMENT:-ONCE PACKED GOODS ARE RECEIVED AT SITE , VISUAL INSPECTION OF PACKING BOXESWILL REVEL WHETHER, THE CASE HAS BEEN RECEIVED WITHOUT ANY TRANSIT PROBLEM.IF THE CASE SEEMS UNDAMAGED, IT IS REASONABLEM

UNPACKING OF THE BOX TO RECEIVED PACKED MACHINE IS AN ART AND IS TO BE DONE WITH SKILLED LABOURS. AFTER ARRIVAL OF PACKING, THE SAME SHOULD BE EXAMINEDTO DETERMINE WHETHER MOISTURE OF ANY KIND HAS ENTERED. AFTER UNPACKING THEMACHINE SHOULD BE CLEANED FROM OUT SIDE AND INSPECTED THOROUGHLY TO SEN

IF THE THE MACHINE IS NOT TO BE INSTALLED IMMEDIATELY, IT SHOULD BE STORED IN DRY,CLEAN SPACE DULY COVERED WITH POLYTHENE PACKING AND SHOULD BE KEPT INCOVERED SPACE ALL ROUND. THL

THE CONDENSATION OF MOISTURE ON WINDINGS LOWERS THE INSULATION RESISTANCE.EVERY MACHINE IS PROVIDED WITH SPACE HEATERS WHICH ARE MEANT FOR BEING KEPTON WHEN THE MACHINE IS NOT IN OPERATION AND EVEN DURING STORAGE OR WHENMACHINE IS NON OPERATIONAL. PROTECTIVE AXIAL LOCKG

THE MACHINE SHOULD NOT DIRECTLY BE KEPT ON EARTHEN FLOOR AND IT SHOULD BESEEN THAT RELATIVE HUMIDITY DOES NOT EXCEED 70% AND TEMPERATURE BELOW 10 DEGC. IS AVOIDED. STORAGE OA


EARING PROTECTION DURING STORAGE

E BEARINGS(IT IS ASSUMED THAT THE MACHINE IS TORED IN FAVOURABLE CONDITIONS).

ED IN A

AMAGE TO THE BEARINGS. IN SUCH CASE FOLLOWING

B) ADS/CORK/PADS AND TURN THE ROTOR 90 DEG EVERY WEEK (i.e. full 360 deg in a month)

T LEAST ONE COPY OF MACHINE RG/OPERATING MANUAL IN THE PACKING BOX

7 GENERAL

SOON AS THE EQUIPMENT RECEIVED AND FOLLOW THE INSTRUCTIONS IN THE BOOK LET.

UIPMENT IS STILL THE RESPONSIBILITY OF THE SUPPLIER TILL WARRANY PERIOD OVER.

. AND THEREFORE, WE EQUEST FOR CRITICALLY VIEWING AND GIVE FEED BACK

B.H.E.L. BHOPAL

B

IF THE STORAGE OF MACHINE IS MORE THEN 2 YEARS (FROM THE DAY OF COMMISSIONING) IT IS PREFERABLE TO RELUBRICATE THS

HERE IN CASE OF ROLLER BEARINGS A PHENOMENON CALLEDSTATIONARY VIBRATION IS VERY IMPORTANT IN CASES WHERE MACHINE HAVING ROLLER BEARINGS IS STORPLACE OF WHICH GOROUND IS SUBJECTED TO SOME VIBRATION IN SHOP FLOORS. THIS IS ALSO CALLED STATIC VIBRATION OR FALSE BRINELLING. DURING PROLONGED STORAGE DUE TO GROUND VIBRATION, THE ROLLER BEARINGS ARE SUBJECTED TO THIS VIBRATION AND MAY CAUSE TO DPRECAUTIONS ARE ADVISABLE:- A) IF POSSIBLE DO NOT STORE SUCH MACHINES ON VIBRATING GROUND.

IF THIS IS NOT POSSIBLE, STORE THE MACHINE ON RUBBER P

REQUEST MANUFACTURER/SUPPLIER TO KEEP AD

1

MANUFACTURERS/SUPPLIERS GENERALLY PROVIDE OPERATING AND STORAGE INSTRUCTIONS ALONGWITH DISPATCH DOCUMENTS AND OTHER TEST CERTIFICATES. IT IS ADVISABLE TO GO THROUGH THE OPERATING INSTRUCTIONS AS IS

GENERALLY BUYER TRIES TO AVOID CALLING REPRESENTATIVES OF SUPPLIER DURING INSTALLATION. OUR SUGGESTION IS THAT EVEN IF BUYER HAS TO PAY FOR THE SERVICE CHARGES FOR DEPUTATION OF SUPPLIER SERVICE ENGINEER, IT IS WORTHWHILE TO CALL HIM SINCE ALL THE PRECAUTIONS ARE NOT POSSIBLE IN A WRITTEN DOWN STATEMENT AND SUPPLIER REPRESENTATIVE WILL TAKE GREAT CARE SINCE SATISFACTORY PERFORMANCE OF THE EQIS

WHILE ON THIS WE WELCOME, SUGGESTIONS AND ADDITIONS REQUIRED TO IMPROVE THIS LITERATURE FOR IMPROVING ITS USABILITYR

A.N. KALE RETD SR. DY. GENERAL MANAGER

motor selection 1

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