OMEC MOTORS
OMT1/2/3/4, TA,TC, MS series Mounting & Maintenance Instructions
Contents
page
1. General information 2
2. Delivery 2
3. Mounting 2
4. Coupling 3
5. Electrician connection 5
6. Connection diagram 7
7. Putting into service 8
8. Maintenance 8
9. Bearing types 11
10. Bearing grease intervals 12
11. Storage 13
12. Motor spare parts and drawing 14,15
Page 1
OMEC MOTORS
OMT1/2/3/4, TA,TC, MS series Mounting & Maintenance Instructions
1. GENERAL INFORMATION
This manual concerns normal three phase induction motors with an output varying from
small to middle size; they are externally cooled, totally enclosed (IC411), supplied in a
cast iron or aluminum frame and provided with ball bearings or roller bearings lubricated
with grease. All motors are suitable for operate with ambient temperature -20℃ up to
+40℃ and altitude till 1000m above sea level.
2. DELIVERY
Before any motor is accepted on site it should be inspected carefully for damage or loss
incurred during transport. Transport damage should be reported with photos to the
supplier.
You should be able to rotate the shaft easily and smoothly with the hand.
Compare the details on the nameplate with those of the power network and with the
requirements of the motor.
3. MOUNTING
Eyebolts supplied with the motor are designed to support only the weight of the
motor.
The motor must be fixed on a stable, clean and flat foundation with good fitting
foundation bolts, using washers. Never mount a motor manufactured for a horizontal
mounting on a surface with an angle of inclination of more than 15 degrees without
consulting the supplier in advance.
Foot & flange motors always have to be mounted in such a way that the drain holes, if any,
are situated at the bottom, otherwise you run the risk that moisture has condensed into the
motor and cannot be drained off. In this case you need to remove the drain plugs.
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OMEC MOTORS
OMT1/2/3/4, TA,TC, MS series Mounting & Maintenance Instructions
Under any exception must be the free flow of air to the cooling fan to avoid the
overheating of the motor. This has to be consider also when motor is mounting in small
rooms with limited space. The ambient temperature must not exceed 40 degrees
centigrade, if more has to be consider with the supplier.
Frame size Min distance to the wall
80 - 100 40 mm
112 - 160 50 mm
180 - 225 90 mm
250 - 315 150 mm
355 175 mm
400 300 mm
4. COUPLING
4.1 Direct coupling
The motor and the driven machine must be mounted in one line to avoid tension on the
shaft. Bad alignment can be a major source of noise and vibrations.
We do not recommend using solid couplings.
4.2 Indirect coupling
Flat or V Belts
Mount the motor on slide rails in order to adjust belt tension. The belt pulley has to be
fitted hard up the shoulder of the shaft. The pulley center line should be within the shaft
center line. Use correctly sized belts with a correct profile and in sufficient numbers to
drive without slip and undue tension. Align both pulleys accurately in such a way that the
center of both pulleys are in line. Multi V belt drives need to be matched sets.
A belt pulley, which is either too small or too wide, or too high, a tension on the belt may
damage the bearing or cause a shaft break. In case of doubt, consult the supplier.
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OMEC MOTORS
OMT1/2/3/4, TA,TC, MS series Mounting & Maintenance Instructions
Spur Gear Drives
The motor and the driven machine have to be positioned in such a way that the two gears
mesh correctly. The motor should then be fixed with dowels.
4.3. Shaft couplings and pulleys etc.
Remove the corrosion protection from the shaft extension and the coupling elements.
The coupling parts, belt pulleys and gear wheels need to be dynamically balanced and fit
easily on the shaft and to be provided with good fitting keyway.
In the factory the rotor has already been dynamically balanced including a half key in
the shaft.
The dimension and the tolerances of the shaft extension and the key are indicated on
the motor dimension sheet.
Assembling the coupling elements has to been done with great care. Careless
handling may damage the bearings, shaft or end shields.
Do not file or grind the shaft to achieve a fit!
When fitting pulleys couplings or bearings, we recommend using heat to elements;
therefore the part to be mounted has to be heated till ± 110 degrees above the ambient
temperature.
A large washer and set screw can be useful for pushing on pulleys using the tapped hole
in the shaft. Only use proper tools for removing the above mentioned parts e.g. pulley
drawers.
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OMEC MOTORS
OMT1/2/3/4, TA,TC, MS series Mounting & Maintenance Instructions
5. ELECTRICAL CONNECTION
5.1. General information
On delivery the motor will rotate clockwise looking at the drive when the phases L1, L2
and L3 are connected respectively to the connection terminals U1, U2 and U3.
Exchanging any two-phase lines can change the direction of rotation.
Connection diagram is shown on the bottom of the motor TBox cover.
When a motor is only suited for one direction of rotation, it is indicated with an arrow on
the motor fan cowl.
Connecting cables must conform to IEE regulations, as must earthing requirements.
Line fuses only protect the cables in case of short– circuiting and do not constitute a
safeguard against the overheating of the winding caused by overload. Therefore it is
recommended that a motor starter and overload is fitted, giving single phasing and
overload protection.
All OMEC motors are fitted in standard with PTC’ s. For windings thermal
protection PTC should be connected.
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OMEC MOTORS
OMT1/2/3/4, TA,TC, MS series Mounting & Maintenance Instructions
5.2. Circuit
Normally our motors are provided with a terminal box with six connections, to which six
leads from the winding are connected either in a delta connection or in a star connection
by means of connection links.
Usually two voltages are indicated on the nameplate of these motors, which means that
the motor can be connected to a circuit having one of these voltages.
If the main voltage is corresponding with the lowest indicated voltage, the winding has to
be connected in delta connection (see figure 1); if it is corresponding with the highest
indicated voltage, the winding has to be connected in star connection (see figure 2).
A motor with e.g. 230/400V on its rating– plate is suited to be switched on directly, on a
circuit with a voltage of 230V between phases with the winding connected in a delta
connection, or on a circuit with a voltage of 400V with the winding connected in a star
connection.
But if the motor is switched on with a star– delta starter the motor is only suited for a
main voltage on the rating-plate, this is the delta voltage. In this case, the connection
strips on the terminal box have to be removed when the motor is connected; the star and
delta connection will be made successively in the starter during the run up. If only one
voltage is indicated on the rating– plate together with the delta sign, the motor can be
switched on directly at the indicated voltage or with a star/delta start.
Pole change motors (for two or more speeds) are connected according to a diagram sent
together with the motor.
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OMEC MOTORS
OMT1/2/3/4, TA,TC, MS series Mounting & Maintenance Instructions
6. CONNECTION DIAGRAM
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OMEC MOTORS
OMT1/2/3/4, TA,TC, MS series Mounting & Maintenance Instructions
7. PUTTING INTO SERVICE
Before putting a motor into service, one should check especially when the motor has not
been used for a long time that the insulation resistance of the winding is sufficient. The
insulation resistance has to be at least 10 meg/ohms on a 1000V megger.
If the insulation resistance is not high enough, the motor has to be dried out and
revarnished or rewound. Check all connections and adjust the thermal protection units to
the correct current. Switch the motor on in a no load state to determine the direction of
rotation. Load the motor gradually and check whether it runs without vibration.
The motor can be used under deviation of the main voltage ± 5% or frequency of max. ±
2% compared to the nominal frequency or nominal voltage, in compliance with the
international regulations for electric machines.
8. MAINTENANCE
The totally enclosed and fan cooled three phase squirrel cage induction motors
require very little maintenance.
Nevertheless it is recommended to check the motor regularly in order to prevent a
breakdown caused by dust, moisture, vibrations, too much or too little greasing.
8.1. Dust
The outer parts of the totally enclosed motors, especially the cooling ribs or cooling
channels, have to be kept as clean as possible in order not to obstruct the cooling air from
the fan extracting the heat from the motor frame.
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OMEC MOTORS
OMT1/2/3/4, TA,TC, MS series Mounting & Maintenance Instructions
8.2. Moisture
Motors, which are not often run, should be started from time to time to prevent moisture
affecting the windings in the long term. Not concern motors with AC Heaters fitted.
8.3. Wear & vibration
To prevent abnormal wear & vibration, one should:
a. take care that the tension of the belt or the chain is not too high;
b. check whether the mounting of directly coupled machines is correct;
c. Check whether the foundation bolts the bolts to fasten the motor and the slide rails are
tight.
8.4. Greasing
Before they leave the factory, the bearings of the OMEC motors are filled with a high
quality Lithium base grease.
The sizes 56 up to and including 250 are provided with shielded/sealed bearings (ZZ-
C3), which have been filled with life-time grease by the manufacture of the bearings.
Motors with sealed bearings and no re-lubrication system require no
maintenance other than checking for noise & temperature during their lifetime.
Sizes 280 up to and including 400, has been provided with lubrication system containing
a grease valve. The lubrication must take place when the machine is running. The old
grease is ejected from the grease valve thus maintaining the correct level and avoiding
overfilling which would be harmful.
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OMEC MOTORS
OMT1/2/3/4, TA,TC, MS series Mounting & Maintenance Instructions
Replacement of ball or roller-bearings
When a bearing has to be replaced, the old bearing has to be removed from the shaft with
proper tools in order not to damage the shaft. Thereupon the bearing location on the shaft has
to be cleaned and checked thoroughly.
To fit a new bearing correctly, heat to 80 degrees centigrade with an electric induction
heater, then slip quickly onto the shaft up to the stop. In the case of a roller bearing only
fit the inner race in this manner. Heating temperature for open bearings is 110℃.
A suitable sleeve may be used to help by tapping gently to seat the bearing home. Note
that under no circumstances must a bearing be driven home cold with excess force. We
must also stress that pressure must not be applied to the outer race of a ball bearing.
Do not mount the end shield until the bearing has cooled down.
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OMEC MOTORS
OMT1/2/3/4, TA,TC, MS series Mounting & Maintenance Instructions
9. BEARING TYPE AND BEARING INSIDE DIAMETER
OMEC Poles Type of bearing Bearing inside
Motor Type Drive End Non Drive End diameter (mm)
OMT2/4/TA/MS/MS 56 2/4 6201 ZZ 6201 ZZ 12 / 12
OMT2/4/TAMS 63 2/4 6201 ZZ 6201 ZZ 12 / 12
OMT2/4/TAMS 71 2/4/6 6202 ZZ 6202 ZZ 15 / 15
OMT2/4/TA/MS 80 2/4/6/8 6204 ZZ 6204 ZZ 20 / 20
OMT1/3/TC 80 2/4/6/8 6204 ZZ 6204 ZZ 20 / 20
OMT2/4/TA/MS 90 2/4 6205 ZZ-C3 6205 ZZ-C3 25 / 25
OMT2/4/TA/MS 90 6/8 6205 ZZ-C3 6205 ZZ-C3 25 / 25
OMT1/3/TC 90 2/4/6/8 6205 ZZ-C3 6205 ZZ-C3 25 / 25
OMT2/MS 100 2/4/6/8 6206 ZZ-C3 6206 ZZ-C3 30 / 30
OMT1 100 2/4/6/8 6206 ZZ-C3 6206 ZZ-C3 30 / 30
OMT2/4/TA/MS 112 2/4/6/8 6306 ZZ-C3 6306 ZZ-C3 30 / 30
OMT1/3/TC 112 2/4/6/8 6306 ZZ-C3 6306 ZZ-C3 30 / 30
OMT2/4/TA/MS 132 2/4/6/8 6308 ZZ-C3 6308 ZZ-C3 40 / 40
OMT1/3/TC 132 2/4/6/8 6308 ZZ-C3 6308 ZZ-C3 40 / 40
OMT2/4/TA/MS 160 2/4/6/8 6309 ZZ-C3 6309 ZZ-C3 45 / 45
OMT1/3/TC 160 2/4/6/8 6309 ZZ-C3 6309 ZZ-C3 45 / 45
OMT1/3/TC 180 2/4/6/8 6311 ZZ-C3 / NU311* 6311 ZZ-C3 55 / 55
OMT1/3/TC 200 2/4/6/8 6312 ZZ-C3 / NU312* 6312 ZZ-C3 60 / 60
OMT1/3/TC 225 2/4/6/8 6313 ZZ-C3 / NU313* 6313 ZZ-C3 65 / 65
OMT1/3/TC 250 2/4/6/8 6314 ZZ-C3 / NU314* 6314 ZZ-C3 70 / 70
* Regreasable at DE only !
OMT1/3/TC 280 2 6314 C3 / NU314 6314 C3 70 / 70
OMT1/3/TC 280 4/6/8 6317 C3 / NU317 6317 C3 85 / 85
OMT1/3/TC 315 2 6317 C3 / NU317 6317 C3 85 / 85
OMT1/3/TC 315 4/6/8 6319 C3 / NU319 6319 C3 95 / 95
OMT1/3/TC 355 2 6317 C3 / NU317 6317 C3 85 / 85
OMT1/3/TC 355 4/6/8 6322 C3 / NU322 6320 C3 110 / 100
OMT1/3/TC 400 2 6317 C3 / NU317 6317 C3 85 / 85
OMT1/3/TC 400 4/6/8 6326 C3 / NU326 6326 C3 /130
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OMEC MOTORS
OMT1/2/3/4, TA,TC, MS series Mounting & Maintenance Instructions
10. BEARING GREASE INTERVALS
By the term “ greasing interval” we mean the number of working hours after which
the bearing lubricant has to be replaced.
Electric motors have such a wide range of application that they must cope with many
adverse conditions as for instance dust, moisture, vibration, temperature, chemicals,
marine atmosphere and of course, the mounting position and loading of the driven
machine.
Generally we can say lubrication life is a product of time, speed and the bearing size. Due
to the impact of all these factors, it is practically impossible to determine any exact values
that are valid under all circumstances. Nevertheless it is necessary to provide at least
some guidelines concerning greasing to the user.
Under normal load and environmental conditions the quality of the grease ensures proper
operation of the motor for about 20 000 service hours with 2-pole designs and 40 000
service hours with multi pole designs. If not otherwise agreed upon the grease need not
be refilled during this period. Nevertheless the condition of the grease filling should be
occasionally checked also within the said lubricating intervals.
The stated service hours are only current under operation with rated speed. For
relubrication thoroughly clean the bearings with a suitable solvent and use the same or
substitute grades specified by the motor manufacturer. Bear in mind, however, that the
bearings should be filled only up to about 2/3 of their free space as a complete filling of the
bearings and bearing covers results in an increased bearing temperature and therefore in
increased wear. For bearings with relubrication facility regrease at the grease fitting with
the motor running according to the grease amount required for the motor in case. The
relubrication intervals should be looked up in the following table:
Construction size Two pole motors Four-pole and multi-pole motors
280 - 400 2000 hours 4000 hours
A chemically aggressive environment, extreme moistness, strong vibrations, high or low
ambient temperatures are not normal circumstances and such conditions must be taken
into account.
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OMEC MOTORS
OMT1/2/3/4, TA,TC, MS series Mounting & Maintenance Instructions
11. STORAGE
Motors should be stored in a dry, vibration free and clean area at normal ambient (-20℃
to +40℃).
Motors should be also stored away from corrosive or chemically damaging fumes.
Shafts should be rotated by hand every half year concerning motors 180 frame and above.
In case if vibrations are unavoidable shaft should be locked. Motors with roller bearings are
supplied with shaft locking device which should be kept in place during storage.
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OMEC MOTORS
OMT1/2/3/4, TA,TC, MS series Mounting & Maintenance Instructions
12. MOTOR SPARE PARTS LIST & DRAWING
Three-phase motor with squirrel-cage rotor
1 Shield B3 DE 19 Bolt bearing cap NDE
2 Fixing bolt shield DE 20 Fan cover
3 Stator frame 21 Fan cover screw
4 Eye bolt 22 Terminal Box screw
5 Feet 23 Terminal Box cover
6 Nameplate 24 Terminal Box gasket
7 Spring washer 25 Connection fixation nuts
8 Bearing DE 26 Terminal board
9 Inner Bearing cap DE from size 180 27 Terminal board holder bolt
10 Key 28 Terminal block PTC
11 Rotor core 29 Blinder
12 Inner bearing cap NDE from size 180 30 Cable gland
13 Bearing NDE 31 Terminal Box house
14 Shield NDE 32 Windings
15 Fixing bolt shield NDE 33 Flange B5
16 Outer bearing cap NDE from size 180 34 Flange B14
17 Fan 35 Bearing cap DE outside
18 Circlip 36 Fixing bolt bearing cap outside
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OMEC MOTORS
OMT1/2/3/4, TA,TC, MS series Mounting & Maintenance Instructions
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