3 phase motor maintenance

8/22/2019 3 phase motor maintenance

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THREE PHASE INDUCTION MOTORSMAINTENANCE MANUAL

Thank you very much for your kind patronage.Well designed and manufactured, Tatung 3-phase induction motors function excellentlyand have the longest service life expectance. To provide you , our customers , withnecessary technical know-how in examination, operation and maintenance of Tatungmotors, we have prepared these instructions. In addition, your attention is also invitedto the stipulations on the nameplate of the motor or in other concerned pamphlets.

These instructions only apply to high-and low-voltage squirrel-cage motors of bothdrip-proof type and totally enclosed fan cooling type, no matter whether they arefoot-mounted or flange-mounted. As to motors of special constructions or for specialpurposes, please refer to their respective attached booklets for information.

Check on receipt

Installation

2.1 Installation environment2.2 Foundation and installation

Means of coupling3.1 Centering3.2 Belt transmission

Running4.1 Check before starting4.2 Starting

Maintenance

5.1 Knock-down examination5.2 Recording

Bearing maintenance

6.1 Tip for maintenance6.2 Construction, classification and application of bearings6.3 Starting the motors for running after stopping running for more than 2 months6.4 Grease Supply6.5 Removal of grease6.6 Problems of poor lubrication6.7 Bearing diagnosis6.8 Makers or brands for grease6.9 Tips for assembling and disassembling6.10 Sealed ball bearing

Vibration

Noise8.

7.

6.

5.

4.

3.

2.

1.


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1.Check on receipt

Please check the following items on receipt.

Read carefully the testing records.Check and see whether the motors are damaged or dirtied;and makesure there is no part or accessory missing and no foreign body in themotors.

Run the motor and make sure the direction of rotation agrees with thatindicated, if there is such an indication . The direction is always indicatedby an arrow plate attached on the motor.

Read carefully the ratings on the main nameplate and other plates orattached pamphlets.

Rotate the shaft manually and make sure it rotates normally. (To preventagainst axial movement of rotors and damages to roller bearings, theshafts of motors of 2 poles and motors with roller bearings are lockedduring transport. Please unlock them before rotating .)

If there are some special requirements, such as, certain particular color,paint, and accessories, please check to see whether they are satisfied.

In case there is any problem or discrepancy found , please contact TatungCompany or its service station nearest to you , and give us the followingin-formation: The type, poles,output capacity, voltage and frequency shown onthe nameplate; also the test number and manufacture number (they are eithermarked on nameplate or on the endface of shaft).

If you are a machine manufacturer , Please pay your attention to the following :

In case the rotors of Tatung motors you received have been locked forabove-stated purpose, you are required to lock the rotors again, either by the

F.

E.

D.

C.

B.

A.


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means described above or by the means shown below:


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2.Installation

2.1 Installation environment

Since well selected environment contributes very much to properfunctioning of motors , you , therefore , must give your carefulconsideration to this matter when you prepare your purchasespecifications . However , to insure operational safety , the followingitems are listed for your information :

Environment temperatureFor standard motors , environment temperature normally has to bewithin the range from -15 to 40.

In case the environment temperature is too high , or excessive heat

is inflected on the motor , protective measures , such as coolingmeasures or heat-insulating measures , should be taken ; or the loadwhich makes the motor over-heated reduced .

On the contrary , if the environment temperature is too low , heatingmeasures will also be necessary .

In case the motor is operated in the environment where thetemperature falls out of the range as stated above , either too low ortoo high , design-wise re-consideration over the insulation , lead wire ,lubrication , bearings fittings , steel parts and weldings of the motor isdeemed necessary .

Good ventilationIf the circulation of cooling air into the motor is broken or impeded ,abnormal temperature rising will occur.

Please keep things at least 20cm off INTAKE AIR ports .

Poorly ventilated environment

If the motor is installed in poorly ventilated environment, improvementsteps have to be taken to guard the motor against being overheated .

If the motor is installed outdoor in moist or dripping environment, stepshave to be taken to guard the motor against being overheated .

Dust

In a very dusty environment , following problems may rise ; and periodicaldusting is recommended .

Open type

A large accumulation of dust on windings and ducts of the corewill result in over-heated windings . Moreover , dust and

moisture retained by it may cause an insulation breakdown . In

a.

E.

D.

C.

B.

b.

a.

A.

d.

c.

b.

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case dust accumulated around rotors is not evenly distributed, illbalance and , consequently , vibration may occur . If dust getsinto the bearings , they may become damaged .

Totally - enclosed type

A large accumulation of dust on fins of frame , theirheat-dispersing effect will be greatly reduced . In case the dustaccumulated on fan or transmission device is not evenlydistributed , ill balance and , consequently , vibration may occur .

Damaging gases and steam

In case damaging gases , such as corrosive gases , inflammable gasesand other chemical gases , or steam exist in the environment , motors ofexplosion - proof type or anti-corrosion treated motors should be chosen ;otherwise , protective or safety measures should be taken . Particular

attention should be placed on motor selection , when inflammable gasesor dust , or steam , which are all in CNS and standards of other countriesto make sure the explosion-proof motors you selected are constructionallysatisfactory .

Accessible site

Sites for installing motors should be accessible, i.e., in an open space sothat motors will be carried to the sites and installed there conveniently .Moreover , the performance of jobs such as inspection , cleaning andmaintenance (especially greasing ) will not be handicapped .

Foundation invulnerable to vibration

Motors should be installed on a solid and hard foundation or floorinvulnerable to vibration from the environment .

Severe vibration from the environment may inflict on motors installedthere in the following damages:

Depressions on roller bearings may occur during the periodswhen the motors are not running .

Windings may break.

The insulation of windings and their connecting wires may bedamaged .

The ground or foundation on which motors are installed must be hard andstable ; otherwise , the amplitude of vibration may become augmentedcontinuously , especially when coupled with machines of high vibratility ,such as crusher and reciprocating compressor .

Vibration of large amplitude while the motor is running may bring aboutthe following failures:

The insulating on the windings may be damaged .a.

I.

H.

b.

a.

3.

2.

1.

G.

F.

b.


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The service life of bearings may become very short.

Parts may get loose or become displaced .

Cooling fan or other parts on rotor may fail due to fatigue .

Power supply

The supplied voltage should be stable , and the voltage drop shouldbe kept to the minimum under loaded condition .

When the motor has to be powered by different voltage andfrequency other than its rated ones , please refer to 4.2C and 5.2Cfor information . if it is not absolutely necessary, please do not dothat , for motors may become over-heated and its performance maybecome undesirable .

Altitude of installation site

In case the sites are more than 1,000 meters above sea level , thetemperature of the motors operated there will be 5 to 10higher .

2.2 Foundation and installation

Foundation laying procedures will not be discussed here . As toinstallation of motors , your attention is invited to the followingdescriptions :

The base of motors should be buried into concrete or grout ofthe foundation to enable the motors to run stably . Do not bendor twist the base . Packers should be placed under the foot ofmotors (weight-bearing parts) and bearing stands . It is alsonecessary to place packers at both sides of base fastening bolts .Allthe packers should be spaced 300 to 500mm from each other sothat they may share the weight on them evenly . It is better touse shrinkage-resist mortar and grout . The base fastening boltscould not be fastened until the mortar around them becomescompletely hardened . Then considerable amount of groutshould placed beneath the base so as to augment the stiffness

of the foundation .

Foundation and base for 2-pole motors

Since the synchronous speed of 2-pole motors reaches as

B.

a.

A.

K.

J.

b.

a.

d.

c.

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high as 3,000 or 3,600rpm , if their foundation is not welldesigned and constructed , resonance may be resulted in .Be very careful , please .

Natural frequency and resonance

National frequencies of 2-pole motors are listed below :

FIRST SECONDIn 50Hz area 3,000cpm 6,000cpmIn 60Hz area 3,600cpm 7,200cpm

If the natural frequency of any other object in theinstallation equals or approximates any one of the valueslisted above , resonance will be resulted in .

If natural frequency (fn) is considered in one free degree ,it may be expressed as :

fn=1/2(gK)/W (1/2)

where g=gravity acceleration

W=weight of coupling machine

K=elastic coefficient of the system

The values of W and K should be carefully chosen that the

value of fn will not equal or approximate any values listedabove . If resonance is noted or suspected when the motoris running , please measure the natural frequency andchange it (see 7 for details ).

Please check the following items upon completion of foundationand installation of motor base :

Check and make sure that the foundation has the stiffnessstated in 2.1H and 2.1I .

Make sure the foundation possesses the stiffness required

to keep the result vibration of the motor and its coupledmachine to the minimum .

Check and make sure the construction is strong enough thatsinking or distortion of the ground and foundation will nothappen .

Check and make sure the concrete constructions havecompleted shrinkage or deformation .

Make sure the foundation and base have been leveled .Coupledmachines should be leveled to each other ; the allowance of

that should be kept under 0.2mm/IM .

C.

e.

d.

c.

b.

a.

b.


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Make sure there are spaces for base bolts , cable wire ,thermometers , space heaters and distribution pipes forconductors ; and find out where they are .

f.


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3.Means of coupling

3.1 Centering

When the motor is directly coupled to driven machine particularattention should be paid to centering . First of all , check the bottomplane of the foot of motor with a level to make sure they are all at thesame level . Secondly , fasten the foot to the base with bolts for trialinstallation . Thirdly , set thedial indicator on the lateralcoupling device and rotate theshaft of motor gently to obtainprecise dimension of A shownin figure 6 . Fourthly , check theinclination between the shaft ofmotor and that of the coupledmachine by inserting thethickness gauge into gap Xshown in figures 6 and make adjustment , by inserting liners , whennecessary to make every B around the disc of coupling device aminimum value possible .

The allowance of A, B and X are listed below :

Rigid CouplingDevice

Flexible Coupling Device

A 0.03mm 0.05mm

B 0.03mm 0.04mm

X 0The value designated by

manufacturers

However , gear coupling or specially designed flexible couplingdevices may have greater allowances than those listed above .Please contact the respective manufacturers for information .

3.2 Belt Transmission

Since V-belts are adopted as transmission means for motors ofmedium capacities , we take these belts as an example for ourfollowing discussion .

- The ratio of diameters of belt pulleys between motor and itscoupled machine is 8 : 1 .

- The speed of V-belt must be kept under 22 to 23 m/sec . If thebelt runs at a speed over 25m/sec., its slip and vibration will beincreased and the belt itself will worn out much faster .

- In case the outer diameter of the pulley is too small , the bending


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force on the shaft will be increased in inverse ratio . If this force goesbeyond the fatigue limit , a broken shaft is impending . in case a widepulley of small diameter has to be adopted for belt transmission ,please consult Tatung sales- engineers when motors are ordered .

- As to belt transmission , the following procedures will apply .

To insure uniform quality , it is ideal to obtain the belts , for onetransmission device , from the same manufacture or the dimensionallowance between the belts be kept within 0.2%. Please remember thatwhen belts are selected. In case some of the belts on the sametransmission device are damaged or worn out , please replace all thebelts there on with new ones , not the damaged or worn ones only . Next ,attention should be paid to pulley alignment , i.e. the shaft of motorshould be kept parallel with that of its coupled machine; or the shafts beat right angle with belts or belt-pulleys.

Proper initial tension on the belts

If the tension is too large , adamaged , even a broken shaftmay be resulted in . On thecontrary, if the tension is too small .slip of the belts will occur ,desirable power transmission couldnot be achieved , and the belts andpulleys will become worn out morequickly.

The initial tension of the belts canbe found out easily by means described below : At the middle pointbetween the shafts of the two belt pulleys , as shown in figure 7 , aweight P is hung on the belt to obtain h1 and h2 . The values h1 andh2 are the differences between the deflections before and after theweight is hung . The approximate values of .

e=2L/(h1+h2) are shown in the following table .

Shape ofV-belt

P (kg) eTransmission condition

Speed of belts OutputC 5 35 16m/s 30Kw

D 10 35 25m/s 150Kw

E 10 45 25m/s 150Kw

You may adjust the adjusting bolts of the base to obtain the tension .the values of e are correlated with the speeds of belts and values ofoutput, and adjustments of the values are necessary .

Another simpler way of measuring the tension is to measure theelongation of the belt; i.e. when the belt is elongated 0.5%, it is

considered to have been mounted with proper initial tension . Afterthe motor has run for ten hours, tension of the belt should be

B.

A.


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checked once again . After the motor has run for one month , thebelt may become permanently elongated , and re-adjustment shouldbe made then .

Replacement of V-belts

When the V-belt is deteriorated it must be replaced; other-wise ,desired transmission can not be obtained . Moreover, because of thediminution of friction coefficient , the deflection strength of the shaftswill increase relatively . That will adversely affect the bearings .Generally speaking, when the permanent elongation of the beltsreaches 1.5 - 2.5% , it should be replaced .

Special belts

Presently , nylon and steel wire belts are marketed in large quantities .In case these belts of high initial tension are to be adopted , high

anti- flexion strength for motor shafts will be required . Please informTatung when order is placed .

D.

C.


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4.Running

4.1 Check before starting

Attention should be paid to the following descriptions before starting .

Distribution line

Please check , against the power distribution diagram , thepower supply , magnetic switch and other protective device ,Star-Delta Starter , reactor , compensator , lead wires forspace heater and thermometers , and the distribution line ofother driven machines .

Insulation Resistance

Make sure the wire connections are well fastened or welded ,their insulation is in good condition , and the terminals areproperly spaced from each other .

Grounding

Check and make sure the frame or terminal box of the motor isgrounded .

Insulation Resistance

To test the stator and rotor windings by their terminal

connectors .

Testing device of 500V be used to test stator windingsbelow 3KV. Stator windings above 3KV be tested by 1000Vdevice . All rotor windings by 500V device .

Insulation resistance varies with rates output . and voltage .insulation classification and rpm of the motor . However , italso varies with the temperature , moisture , dust riddencondition , service period , testing voltage and testingperiod. Owing to the foregoing insulation resistance (R) can

not be measured . However , the following rule will apply .3M ohm for rated voltage above 600V.

1M ohm for rated voltage below 600V.

or , formulae from J EC - 146 may apply ;

R(rated voltage) /rated output(KW)+1000(M ohm)R(rated voltage + rpm/3) / rated output (KW) +2000+ 0.5 (M ohm)

In case insulation resistance becomes low , the winding s mustbe dried by hot air , by vacuum , or by electrical current (shortd.

D.

C.

B.

c.

b.

a.

A.


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circuit , low voltage when unloaded , and DC current ) as thesituation dictates . In case resistance can not be brought up todesired level after drying , some defects may exist . Pleaselocate and repair the defects . In case , the job can not be done ,please contact Tatung company or its service station nearest to

you .

Lubrication

Motors are well greased during assembly . However . it may be avery long time from the completion of assembly in our plant to thebeginning of running in your factory ; it is necessary to make somereplenishment . Tatung motors are greased with SHELL ALVANIAR3, when replenishment is made , please use the same orcomparable products . For motors of special types , the specificationand quantity of grease to be used are stipulated on respectivenameplates.

Check and make sure the coupled machine is in good condition . Couplingcondition , tension of the belts and fastening devices should also bechecked.

Rotors of 2-pole motors or motors with roller bearings have often beenlocked during shipment , please make sure it can be rotated freely .

Check and make sure there is no foreign body left in or get into the motoror its coupling machine during assembly or shipment .

4.2 Starting

Starting load

As a general rule , motors are started without load for test running .Only after being proved normal it can be coupled with driven machinefor further test . Motors are usually started with light load andswitched to full load after full seed is reached , except otherwiserequired .

Direction of rotation-when viewing from non-drive end clockwise rotation isconsidered correct . After the terminal connectors U.V. and W (or 1,2 and

3) being connected to the connector R,S and T from power supply , themotor rotates counter-clockwisely , interchange any 2 of the 3 connectingleads . Most motors can rotate both way . However , 2- or 4-pole motorswith high rpm or 6-pole motors with large capacities , their direction ofrotation has to be limited to either clockwise or counter-clockwise . In thiscase , a plate bearing an arrow to show the direction of rotation will beattached to the motor.

Supplied voltage and current

make sure supplied voltage agrees with or within 10% of thatshown on the nameplate . If the difference between ratedvoltage of the motor and supplied voltage , the windings may

a.

C.

B.

A.

H.

G.

F.

E.


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become overheated .

Make sure supplied 3-phase voltages is in balanced conditionamong phases. A little bit difference among them , unbalancedcurrents of considerable values may be resulted in .

Make sure phase currents are balanced , otherwise windings willbe exceedingly overheated and torque can not be provided.Sometimes , abnormal noise and severe vibration may beaccompanied .

Frequency

The maximum variation between rated and supplied frequenciesshould be within 5% under the rated voltage . If both voltage andfrequency varies at the same time , the SUM of their absolute valueshould be within 10% .

Starting

In case the first starting is a failure , restarting can be made .However , as a principle , only two successive cold starting can bemade at a time . If both efforts are failed , a 30 minutes intervalshould be allowed for primary and secondary conductors to get cold ,which have been heated by starting current during these failedstartings .

Starting time and noise

In case GD 2 of coupling machine is large , a longer starting timemay required . However , if it is difficult to start or starting time isexcessively long , and sever noise is noted during start , pleasecontact Tatung or our nearby service activity .

Vibration

Determine the value of vibration with vibration meter or by feelingand compare that obtained with the data shown in Section 7 -Vibration . After this is completed, let the motor run alone. Then , runwithout load and then , run with full load . If nothing wrong during

start , keep the motor running for 3 hours and take down the recordsevery 15 minutes as stipulated below (5.2). In case nothing abnormalhas been found , the motor will be kept on running and checks madeevery few hours. Still, there is nothing abnormal , the motor isconsidered serviceable and may be put into service .

G.

F.

E.

D.

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5.Maintenance

5.1 Knock-down examination

For motors running continuously day and night , a knock-downexamination should be made every 2 or 3 years. However , formotors designed for special purposes , knock-down examinationsshould be made in certain time periods prescribed respectively .

5.2 Records

Every day records

At what time (year, month, day and hour) and in whatweather the test is conducted .

Voltage. load current . frequency (see 5.2C).

Ambient temperature (room temperature).

Temperature and noise around bearings.

Temperatures in stator windings and on frame surface(totally enclosed type). See 5.2C.

Abnormal vibrations and noise (see sections 7 and 8).

Records of periodical test and inspection

Insulation resistance and the relative humidity (see4.1D).

Amplitude of vibration (see 5.2C and section 7).

The color and contents of grease discharged frombearings.

Dirt lodged in and on the motor.

Coupling allowance of coupling device; the tension of

belts.

Fastening bolts for base . foot and other parts.

In case of oil lubrication , surface condition andclearness of the oil should be recorded. At the sametime , check and make sure there is no leakage.

Some of the values obtained by above-listed tests andinspections are variable; their variable ranges given below :

The variation of voltage must be within 10% of rated

voltage. The variation of frequency must be within 5%

a.

C.

g.

f.

e.

d.

c.

b.

a.

B.

f.

e.

d.

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b.

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of rated value . when rated voltage is applied. whenvoltage and frequency varies at the same time , theresult of absolute values of the two variations must bewithin 10%.

Temperature rise (maximum ambient temperature of40) by TM and RM are listed below :

TM : THERMOMETER METHOD

RM : RESISTANCE METHOD

PartInsulation A Class E Class B Class F Class H Class

Type TM RM TM RM TM RM TM RM TM RM

StatorWindings

Types otherthan TEFC

50 60 65 75 70 80 85 100 105 125

TEFC 55 60 70 75 75 80 90 100 110 125

RotorWindings

Types otherthan TEFC

50 60 65 75 70 80 85 100 105 125

TEFC 55 60 70 75 75 80 90 100 110 125

Bearing

40when test is made at the outer surfaces.45when test is made by inserted thermometer.However , when hot resist grease is used forlubrication , the temperature rise can reach as highas 55.

Vibration (see Section 7 for detailed information)

Bearings : When their service life is compared withthat of windings , the allowable values , whenmotors are running with load are listed below :

25 - 30 for 2-pole motors

50 - 60 for 4-pole motors

70 - 80 6-and -more-pole motors

In case the vibration measured exceeds the abovelisted values , please check and find out the trouble ,and corrective measures be adopted soonest .

5.3 In case periodical maintenance is necessary , it should be done inaccordance with the table attached at the end of this pamphlet .

c.

b.


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6.Maintenance of BearingsIf not particularly prescribed , rolling bearings lubricated with grease are usuallyadopted for motors. Except close-type ball bearings , all other bearings are of opentype so as to prevent from being over-greased by facilitating the injection and discharge

of grease. Tips of maintenance are listed and explained below :

6.1 Tips for maintenance

6.2 Specifications , applications and const ructions of ball and roller bearings

6.3Af ter stopping running for a long period (more than 2 months)

6.4Grease supply

6.5 Removal of grease

6.6 Problems of poor lubr ication

6.7 Bearing Diagnosis

6.8 Makers or brands of grease

6.9Tips for assembling and disassembling

6.10 Sealed ball bearing

6.1 Tips for maintenance

Additional supply of grease should be given to the newly procured motorsbefore they are started running , or to the motors have stopped runningfor more than 2 months before they are re-started for running.

After motors having started running . additional grease should be suppliedat intervals and according to the quantities shown on nameplate.

The discharged grease should be removed timely .

6.2 Specifications , applications and const ructions of ball and roller bearings .

The information is given in the following table , except that for speciallydesigned motors :

Application Non-drive end Drive end

Foot-mounted andbelt coupled motors

Single shaftDeep grooved ball

bearing63CM

Roller bearingNU3CM

Foot-mounted motors

coupled by couplingdevices

Deep grooved ball

bearing63CM

Deep grooved

ball bearing6.3CM

C.

B.

A.


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Vertical mountedmotors coupled by

coupling devices

Without or withlight thrust

Deep grooved ballbearing

63CM

Roller bearingNU3CM

Small thrustDeep grooved ball

bearing

73

Roller bearing

NU3CM

Medium thrustMultiple-row bevel

ball bearing73

Roller bearingNU3CM

1 Grease nipple 8 Rolling bearing

2 Grease injection pipe 9 Shaft

3 Outer bearing-cap 10 Grease exit cover

4 Lock washer 11 Cover set-screw

5 Lock nut 12 Bolt

6 Bearing bracket 13 Bearing housing

7 Inner bearing-cap

6.3 After stopping running for a long period (more than 2 months) :

Make sure checks described in item 1 and 4 have been completed .

After beginning running , grease should be injected at once . The quantityto be injected is shown on nameplate .

Temperature rise around bearings after beginning running .

Loudness and tone of bearing noise .

Noise and vibration of the motor .E.

D.

C.

B.

A.


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Vibration of the bearing .F.


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6.4 Grease supply

Grease supply is considered the most important thing in bearingmaintenance . The primary purpose of grease supply :

- To keep the sliding surface lubricated .

- To maintain a grease film between rolling surfaces so as to facilitateload-carrying and resist wear . No noise will be heard if grease filmis not broken and sliding surfaces properly lubricated .

- To wash out the deteriorated grease and particles from worn part .

- The existence of grease will make the bearing corrosion proof .dust-proof and minimize the vibration and noise .

Make sure grease is supplied according the quantities and time intervals

indicated on the nameplate .

For motors which have stopped running for more than 2 months , asupply of grease should be given when they are started to run again .

When too much grease is supplied , bearings will become overheated andmaintain in this condition continuously ; when too little grease is supplied ,grease may not be able to circulate to the inner part of bearings .

interval between grease supplies

If the motor runs 24 hours every day , the interval between supplies

is indicated on name plate . If the motor runs 12 hours one day and 8or 3 hours the other day , it will be considered as running 12 hoursevery day for deciding the interval of grease supply so as to insuregood lubrication .

Table A Quantity And Interval of Grease Supply Ball bearing

BearingNo.

Firstfilling(1)(g)

Consecutivesupplies (2)

(g)

Interval between grease suppliesfor Motors runs 24 hourseveryday (in days) (3)

2-p 4-p 6-p 8-p 10-p 12-p

6310,6210 50 30 120 180 180 180 180 1806311,6211 100 30 120 180 180 180 180 180

D.

C.

B.

A.


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6312,6212 100 30 120 180 180 180 180 180

6313,6213 100 30 120 180 180 180 180 180

6314,6214 200 50 80 180 180 180 180 180

6215,6214 200 50 - 180 180 180 180 180

6316,6216 200 50 - 180 180 180 180 1806317,6217 200 50 - 180 180 180 180 180

6318,6218 300 50 - 180 180 180 180 180

6320,6220 400 80 - 120 180 180 180 180

6322,6222 600 80 - 120 180 180 180 180

6324,6224 600 80 - 120 180 180 180 180

6326,6226 1000 100 - - 180 180 180 180

Table B Roller bearing

BearingNo.

Firstfilling(1)(g)

Consecutivesupplies (2)

(g)

Interval between grease suppliesfor Motors runs 24 hours everyday(in days)(3)

4-p 6-p 8-p 10-p 12-p

NU3

NU2

NU22

14 100 50 180 180 180 180 180

15 100 50 180 180 180 180 180

16 100 50 180 180 180 180 180

17 200 50 120 180 180 180 180

18 200 50 120 120 180 180 180

20 300 80 120 120 180 180 180

22 300 80 120 120 180 180 18024 400 80 - 120 180 180 180

26 600 100 - 120 180 180 180

Remarks :

Quantity for first grease filling is the amount to be supplied after aknock-down clearing of bearings . 1/3 of which will be placed in thebearing, the rest in bearing covers .

Supply quantity is the amount of grease to be supplied each time after

proper interval .

If the motor runs 8 hours one day and 12 or 6 hours the other day , themotor will be considered running 12 hours every day . The intervalindicated in above tables may be doubled .

In case , the motor stated in c. is a 2-pole machine and 4- or 6-polemachine with roller bearings in large diameters (NU322 and above), theinterval between grease supplies should not be doubled .

Please do not try to prolong the interval by increasing supplied quantity .

For 2-pole motors or 6-pole motors with roller bearings of large diameters ,have started running after stopping running for more than 2 months ,

6.

5.

4.

3.

2.

1.


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grease should be supplied according to interval and quantity indicated onthe nameplate . Otherwise, noise may be heard and abnormal worn ordamaged bearings my be resulted in .

6.5 Removal of grease

When the storage for grease discharged from bearing is filled ,bearing may become over heated on account of viscidity resistanceand grease leakage may occur . Therefore , please open the exitcover and let the grease out timely .

6.6 Problems of poor lubrication

Properly Lubricated Poorly lubricated

SoundOnly very weak soundcould be heard from

lace and retainer

Large noise from retaineror 2-pole motor's roller

bearings .

Service life

The existence of oil filmon various lubricatedsurface wear is greatlyslowed down and longservice life of bearingsexpected

Due to broken oil film ,metal surfaces may contacteach other . Excessivewear may occur and veryshort service life ofbearings may be resulted in

HeatFrom viscidityresistance.

From the friction of directcontacting of metalsurfaces .

Damage

Damage and noise causedby metal dust . Burntretainer . Deformed orbroken rolling bodied andouter and inner wheels .

Vibration

Gaps between wornretainer , rollers and ballswill get larger ; deformationand vibration may beresulted in .

Damagedbearings willgive a burntmotor

When bearings are

damaged , rotor will comedown and be in contactwith stator . Heat from theirfriction will burn thewindings .


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6.7 Bearing Diagnosis

If new grease is supplied and deteriorated grease dischargedproperly , the motor will run smoothly . When motors can not run well

on account of trouble of bearings , tips for diagnosis are given below :Noise from bearings .

Temperature rise of bearings .

Temperature rise is defined as the difference between thetemperature of bearings and that of their surroundings . Its value isusually expressed as. The allowable temperature rises are given infollowing table . However , when the temperature rise exceeds 40,please check and see whether there is anything wrong .

Values of

temperature rise(ambienttemperature 40)

Readings fromthermometers Specifications

Cap grease 40 80

CNSJ ISJ ECJ EM

2934C4202371020

Heat-resistgrease

55 95CNSJ ECJ EM

2934371020

When temperature rise varies during running , consider the following :

The viscidity resistance of newly supplied or discharged grease .

Insufficient grease or deteriorated grease .

Grease in bearing caps or on retainers falls into the bearing andviscidity resistance there in increases abruptly .

The variation of load will cause the temperature of motor to goup .

d.

c.

b.

a.

B.

A.


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Variation of bearing vibration

As rolling surfaces and steel balls or rollers become worn , the gapsbetween them will become larger and the vibration will also becomeworse . Poor lubrication and insufficient compression force of lockingwasher , axial vibration may occur and whistling sound may be heard .In addition to deformation of and defects on balls , rollers and

retainer , defects on rolling surfaces may also cause the vibration tobecome abnormally intensive .Therefore , it is very important to findout the causes of intensified vibration and take corrective measures .

General appearance of discharged grease

Color andodor

- White mixture may be considered as air and watermixed into the grease when churned by the bearings .- The grease in a new machine may become dark dueto the grindings from rough surfaces . In this case ,check and see whether the metal dust has got into the

bearing .- In addition to chemical change , dust , air bulbs andwater may mix into grease and make it deteriorate ,discolor and smell bad.

Hardness- Insufficient supply of fresh grease , old grease willremain in the grease groove . Fresh grease will getinto the groove when sufficiently supplied .

Foreignbodies

- Matters other than grease may be wrongly injected ;dust may get in .

6.8 Makers or brands of grease

All Tatung motors are greased with SHELL ALVANIA R3. Pleaseadopt grease of the same brand or other qualitatively comparableproducts for grease supply .

Before you decide what maker or brand of grease will be chosen ,please consider the following descriptions :

AVAILABILITY :Choose the products of a world-wide supplier sothat they will be always available .

TEMPERATURE :

Temperatures where in regular greases are

serviceable range from -20to 120. Beyondthis range , greases for low or high temperature

D.

C.


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should be adopted .

For high rpm motorsand motors withbearing of largediameters

Harder grease has better compression strengthwhile softer ones may give minimum noise andvibration and allow an easy operation in injectionand discharge . (Silicon grease prohibited.)

LOAD- BEARABILITY :Grease of good compression strength for heavilyloaded operation (belt or gear transmission).Silicon grease prohibited .

Moisture-proof :Na-grease or Ca-grease is recommended formotor installed in moist environment .

Viscidity :

Among different brands of grease with samehardness , the one with lower viscidity isrecommended to minimize noise , vibration andtemperature rise of bearings after greasing andto provide good lubrication during cold weather

and easy operation in grease injection anddischarge .

Serviceability :The better you understand lubrication productsthe wiser decision you will make in greaseselection .

Mixture of different grease

Greases of same base (for example Li-base) and same category (forexample mineral oil) but with different viscosities may be mixed together. Incase grease to be supplied is different from that already in the bearings , and

you have no other choice but take it for replenishment , please inject a verylarge quantity of the supplied grease so as to replace all of that already in thebearing .

6.9 Tips for assembling and disassembling

Figure 13 Disassembling tool Bearing shaft bolts

Figure 14 Ball bearing Disassembling tool for ballbearings

Figure 15 Inner ring of roller bearing, NUtype Disassembling tool for rollerbearings


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If the bearing disassembled from a shaft or otherobject is serviceable , please wash it with machine oilor coal oil . Or it be wrapped well , without washing ,to prevent moisture and dust from getting in . Thedisassembling be made in accordance with the

procedures shown in the figures above . The pullingforce be evenly distributed in the inner ring of thebearing .

The procedures below are for bearing assembling(contraction fitting)

The bearing should be heated evenly , it can not be in direct contact withcontainer . Please churn the oil sufficiently .

To prevent from deformation and being tempered , bearings are notallowed to be heated , even locally , over 120. Put bearing in the oiland heat them gently to 100; then pick out the bearings for contractionfitting .

Vanes and inner bearing cap should be assembled first , if necessary .

The side marked with specification or model should face the viewer .

After contraction fitting , it should be pressed or hammered to make it intight contact with the enface of bush . When pressed or hammered , theforce must be directed to and evenly distributed on the inner ring asindicated in figure 19. Figure 18 shows the wrongful practice which is

absolutely prohibited .

In addition to what stated above, you must also keep in mind thefollowing procedures :

Make sure grease passages on bearing caps and brackets arealigned with each other .

The primary supply of grease should be filled into the bearingand its caps.

Sealing material should be applied into the joins of out-door typemotors .

6.10 Sealed ball bearing

3.

2.

1.

e.

d.

c.

b.

a.

B.

A.


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Construction

Sealed ball bearing has sealing plates on both sides while open-typebearing has not . Because of this difference in construction , theformer has much longer interval between greasing .

Knock-down examination

Knock-down examination should beconducted each 2 or 3 years. After themotor has been in service for about twoyears , the bearings should be checked withstethoscopes rod for abnormal noise ; andthey may be replaced with new ones if the result obtained by thecheck so indicates. The sealing plates of sealed ball bearings may bedismantled for replacing grease. However , before the fresh grease isfilled , the deteriorated grease should be thoroughly washed off withbenzene or coal oil .

B.

A.


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7.Vibration

Severe vibration may adversely affect thewindings , bearings and coupling mechanism

thereby causing them breakdown . When motoris running with load , the values of vibration mustbe no more than those listed in 5.2C. In addition ,figure 21 also serves as a basis for decidingwhether the motor is serviceable due to vibration .In case the values of vibration have gonebeyond desired values , please try to find outwhere the trouble lies and see whether remedialmeasures may be adopted .

(Remarks : In case the main vibration reaches values up to 2,000 rpm , evenif the motor actually rotates at 1,000 rpm , the vibration should be consideredas 2,000 rpm rotor .)

The list below is for your information :

Electrical Vibration

Vibrations Description CauseRemedialmeasures

Vibrationscaused bydistortion ofmainmagnetic flux

Vibrationfrequency=2f.Nothing to dowith load.Proportionalto V 2.

Natural vibration frequencyof multiple-nod distortedstator approximates 2f.

Stabilize

stator core.

Check andsee whetherstiffness offoundation issufficient.

Vibrationcaused byunbalancedmainmagnetic flux

Vibrationfrequency=2for f/pxm (m=1.2);yielding anoise by 2sf.Stator shakesin certaindirections.Severevibration notproportionalto voltageand havingnothing to do

with load.

Distorted rotor givesnon-uniform air gapPerimeterwise-dis-tributedwindings are not evenUnbalanced rotor givesvibration of great magnitude .

Natural vibration frequenciesof foundation stand, statorand rotor approximates thefrequency of power source .

Repair therotor toobtainuniform airgaps Adjustwindings toobtainbalancedflux.Reducebearinggaps.Installvoltagebalancingline.

Test thestiffness of

a.


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foundation.Vibrationcaused bymutual actionforces

betweencurrents ofstator androtor

Vibrationfrequency=2f.Large

magnitude atstarting orwith load.

Unbalanced windings (brokenwire or unbalanced

resistance in secondarycircuit .

Balance the

windings.

Vibrationcaused bypulsatingtorque

Vibrationfrequency=2f.Vibratingforce actingtoward theperimeter ofrotor.

Unbalanced voltage source.Unbalanced windings.

Adjust thevoltage andwindings.

Mechanical Vibration

Vibrationcaused byunbalancedweight

Vibrationfrequency= n.

Unbalancedresiduum.Unevenlyaccumulateddust.Dried insulation.Eccentricdeformation by

heat.Worn vanes

Dynamicbalancing.Cleaning andrepairing.Replace wornvane and cutter.

Vibrationcaused by bentshaft

Vibration frequency= n.

Bending causedby externalforce.Deformation byheat.

Straighten orreplace bentshaft.

Vibrationcaused bycylindricallydeformed shaft

Vibrationfrequencies=2n,3n

Elliptic ortriangular shaftsection .

Repair deformedshaft.

Vibrationcaused bydefective rollingbearings

Vibration frequencyuncertain .

If vibration iscaused by defectiverolling surface ,frequency=numberof balls in thebearing x N (naturenumber)

Depressioncaused byexternalvibration duringtransport ornone runningperiods.Damaged byover load orworn outthrough normaluse.

Replace thebearing.

b.


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Vibrationcaused byill-installedrolling bearing

,uncertain.Larger axialvibrationmagnitude.

right angle withrolling surface.Distortedbracket.

Repair the shaft.Knockdown forreassembling.

Vibrationcaused bycharacteristicsof bearings

Frequencyuncertain .Larger axialvibration .Nothing to do withrpm .

Non-linearcharacteristics.Resonantbrackets.Excessivegaps.

Pre-compressionReduce gapsReplace bearingsModify fittings,change grease.

Oil-whip

Frequency = n/2.Occurs when speedis 2 times ofdangerous speed orabove .

Self-excitedvibrationcaused by oil

film.

Grease of lowviscosity.Reduce the widthof bearings.Enlarge bearinggaps.Check thediameter at theneck of shaft.

Vibrationscaused bydistortioncouplingdevices ofdriven machine

Frequency = n.Vibrationdisappears whenuncoupled.

Mal-alignmentbetween shafts.Insufficientstraightness ofshaft.

Adjust thecouplingRe-alignment ofcoupling device.

Vibrationcaused byimproperinstallation(resonancewith installationsystem)

Vibration frequencyequals n, 2n; f, 2f.

Motor base andfoundation arenot properlycoupled withdriven machine.Resonancebetweenvibrationsystem of bothsides.

Adjust theinstallationsystem .Change naturalfrequency of thesystem.

f: frequency s: slip p: pole pairs m: integer n: rpm

If the motor vibrates severely during running , cut off the power supply andsee whether the vibration is mechanical or electrical . Next , vary the loadwhen the motor is running or let it run without load for determining the causeof vibration .

Measure and alter the natural frequency.

Measuring natural frequency by strike test.

A synchronous vibration meter be attached on one side of the upper part ofmotor . Then collide the motor at the other side of the meter , as illustrated infigure 22. The test should be conducted both axially and laterally. Natural

frequencies obtained by this test should be within the ranges below :


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In 50Hz Area : Below 2000cpm, 3600-4800cpm , and above 7400cpm.

In 60Hz Area : Below 3000cpm, 4400-6000cpm , and above 8000cpm.

If any natural frequency falls beyond the above ranges , an adjustment of

base cotter may be considered , or additional grout be poured into or aroundthe base to rise up the natural frequency . The reason why we recommendgrout instead of concrete is that the latter shrinks.


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8.Noise

8.1 Noise be measured based upon JEM 1020

Microphone be placed 1 meter from the motor at the same height of itsshaft.

Make 4 measurements around the motor , and take the average of theobtained values as the noise level.

A-scale be adopted for noise compensation circuit.

8.2 Reflexion from the surrounding (room coefficient) and noise from thesurrounding

Noise measuring should be conducted in the surrounding with

minimum reflexion . In a concrete building , space of the room ,facilities in the room and the relative positions of machines contributea great deal to reflexion , which , in turn , influence the measurednoise level . Therefore , below the range of 3dB(A), the measurednoise level may become louder than actual level.

When the noise level of the motor equals that of the driven machine ,their result is augmented by 3dB; when the difference between themis 6dB, the higher level is augmented by 11dB; when the difference is10dB, the higher level dominates. Should corrective steps be taken ,machine with higher noise level must be adjusted first.

Check points for routine maintenance

Part To BeChecked

Period OfCheck

Items To Be CheckedCorrectiveSteps

MotorFrame

Annually vibrationVibration meter,Feeling

Find out thecause ofabnormalvibration andcorrectivesteps taken.

Annually NoiseHearing,Stethoscopesrod

Make a surveyof the site.

AnnuallyTemperatureof frame

Feeling orThermometer

Check powersource, loadand dustaccumulatedon fins.Correction bemade.

AnnuallyDirt on theframe

Check and see

c.

b.

a.


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Annually Ventilation

Temperature ofcirculating air,by feeling orthermometer

whether theinlet and outletof air areblocked.

Clean theblinds, air netsand air filters.

PowerSource

AnnuallyVoltage &current

Electricalmeasuringmeters

Check and seewhether thereis any changeof the ratedvalue.

Bearing

AnnuallySound frombearings

Stethoscopesrod

Grease besupplied andremoved as

prescribed onnameplateSurface layerand color ofthe oil.

Look up 6.1,6.2 and 6.3 forinformation .

AnnuallyTemperatureof bearings Thermometer

AnnuallyVibration ofbearings

Feeling orVibration meter

TimelyDischargedgrease

Color, hardnessand foreignbodies.

Annually Oil leakage

Inside TheMotor

Every 6Months

Mega ohm ofwindings

Mugger

Periodiccleaning.

Annually Bad odor Open typemachine

Annually DirtDust, foreignbodies andwater.

Others

Annually Coupling statusCoupling devicebelts cougars.

Stop the motorfor checking.

AnnuallyProtectivedevice

Make sure theyare inserviceablecondition.

Annually Fasteningdevice

Foot-fasteningbolts and otherfasteners.


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The structure of 3induction Motor. Squirrel Cage. Rotor , Enclosed-Ventilated type1.Bearingbracket

8.Fastening boltsfor air guiding

plate

15.Shaft holesealing device

22.Preload spring

2.Fastening boltfor bracket

9.Fastening boltsfor bracket

16.Rotorfastening key

23.Air-guidingplate

3.Fastening boltsfor air guidingplate

10.Bearingbracket

17.Rotor core,end-ring &vanes

24.Terminal plate

4.Eye bolt11.Air guidingplate

18.C-clamp 25.Terminal cover

5.Frame12.Key atshaft-end

19.Shaft holesealing device

26.Terminal cover

6.Stator core 13.Shaft20.Ball bearing,

sealed type

27.Terminal

fastening bolts7.Stator winding

14.Ball bearing,sealed type

21.Duster 28.Terminal box

The structure of 3Induction Motor. Squirrel Cage Rotor Totally-Enclosed Fan-Cooled1.Eye bolt 9.Bearing

17.Inner

bearing-cap

25.Outer bearing

bracket


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2.Stator core.

end18.Bearing 26.Bracket

3.T-box 11.Shaft 19.Lock nut27.Greasenipple

4.Fastening

bolts forbracket 12.Lock nut 20.Fastener for fan

28.Fastener for

fan hood

5.bracket13.Fasteners forinner bearingcap

21.Hexagonal headbolts

29.Inner fan

6.Inner bearingcap

14.Grease outlet 22.Lock-washer30.Fasteningring

7.GreasingPipe

15.Fastener foroutlet cover

23.Fan hood31.Statorwinding

8.Outer bearingcap

16.Rotor core.end ring

24.Outer bearingbracket

32.Frame

3 phase motor maintenance

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