Omec OMT2 Manual

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–Mounting & Maintenance Instructions –
OMT1 & OMT2 Motors

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Inhalt Seite
1General information 3
2Delivery 3
3Mounting 3
4Coupling 3
4.1 Direct coupling 3
4.2 Indirect coupling 4
4.2.1 Flat belt or V-belt 4
4.2.2 Spur gear transmission 4
4.3 Shaft couplings 4
5Electrical connections 4
5.1 General information 4
5.2 Circuit details 5
6Putting into service 6
7Maintenance 6
7.1 Dust 6
7.2 Moisture 6
7.3 Wear & vibrations 7
7.4 Greasing 7
7.5 Replacement of ball or roller bearing 7
8Bearing types 8
9Regrasing interval of bearings 8
10 Disposal 9
11 Motor spare part list / exploded view 10

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1General information
This manual concerns normal three phase induction motors with an output varying
from small to middle size; they are externally cooled, totally enclosed, supplied in a
cast iron or aluminium frame and provided with ball bearings or roller bearings,
lubricated with grease.
2Delivery
After receipt, remove the package material, if any, and mind the parts that have been
delivered loose.
Check the motor to see whether transport damage has occurred.
You should be able to rotate the shaft easily and smoothly by hand. Compare the
details on the nameplate with those of the power network and with the
requirements of the motor.
3Mounting
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 risk that moisture will
condensate in the motor and cannot be drained off. To this end you need to remove
the drain plugs.
Under no circumstances the entrance of cooling air, drafted by the cooling fan, may
be obstructed. This will cause overheating of the motor. Special attention is required
where motors will be located in small enclosed rooms.
The ambient cooling temperature must not exceed 40 ºC, unless otherwise agreed
upon at the time of ordering.
4Coupling
4.1 Direct coupling
The motor and driven shafts must be accurately aligned. In case of a flexible coupling,
the manufacturers distance between the parts to be coupled must be adhered to,
also the degree of misalignment must be within the makers tolerance. We do not
recommend using solid couplings.

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4.2 Indirect coupling
4.2.1 Flat belt or V-belt
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.
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.
4.2.2 Spur gear drives
The motor and the driven machine have to be positioned in such a way that the two
gears align correctly. The motor should then be fixed with dowels.
4.3 Shaft couplings
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 half-key balanced.
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 be done with
great care. Careless handling may damage the bearings, shaft or end shields.
Do not file or emery on the shaft to achieve a fit!
When fitting pulleys couplings or bearings, we recommend using heat elements;
therefore the part to be mounted has to be heated till ± 100°C. A large washer and
setscrew 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.
5Electrical connections
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,V1 and W1.
Exchanging of any two-phase lines changes the direction of rotation. When a motor is

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only suited for one direction of rotation, it is indicated with an arrow on the motor
fan cowl.
Connecting cables must comply with the IEC regulations. 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 start- and overload protection is mounted, giving single phase and overload
protection.
5.2 Circuit details
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
rating–plate of these motors, which mean that the motor can be connected to a
circuit having one of these voltages.
If the mains 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 230 V between phases with the winding
connected in a delta connection, or on a circuit with a voltage of 400 V with the
winding connected in a star connection.
V2
U2
W2
W1
V1
U1
Δ- Connection
low voltage
L1 L2 L3
Abb. 1: Delta connection
V2
U2
W2
W1
V1
U1
Y- Connection
high voltage
L1 L2 L3
Abb. 2: Star connection
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/delta connection will be made successively during the start up.

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If only one voltage is indicated on the nameplate together with the delta sign, the
motor can be switched on directly at the indicated voltage or with a star/delta
starter.
Pole change motors (for two or more speeds) are connected according to a diagram
sent together with the motor.
6Putting 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 1.000Ωper Volt, what means at
least 400.000on a supply voltage of 400V.
If the insulation resistance is not high enough, the motor has to be dried out
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 a variation of the main voltage ± 5% or
frequency variation of max. ± 2% compared to the nominal frequency or nominal
voltage, in compliance with the international regulations for electric machines.
7Maintenance
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.
7.1 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.
7.2 Moisture
Motors that are stalled for a long time, should be started from time to time to
prevent moisture affecting the windings in the long term. Before putting the 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.

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7.3 Wear & vibrations
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 to fasten the motor and the slide rails are
tightly fixed.
7.4 Greasing
Before the motor leaves the factory, the bearings are filled with a high quality
Lithium base grease. This grase can be mixed with most of the commonly used ball
bearing greases that are lithium-based so that nearly every grease can be used for
regreasing.
Motors from frame size 56 up to frame size 250 are fitted with both sides sealed ball
bearings ( 2RZ ) those filled with grease by the bearing manufacturer “for life time”.
The bearings for those frame sizes without regreasing-divices are completely free of
maintenance. Regular checks can be limited only towards temperature and noise.
Motors from frame sizes 280 up to frame size 400 are equipped with open bearings,
that are filled for 2/3 when the motor leaves the factory. The drive-end shields are
fitted with bearing covers. The lubrication must take place when the machine is
running. The old grease ejects from the grease valve thus maintaining the correct
level and avoiding overfilling which would be harmful.
7.5 Replacement of ball or roller bearing
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.
After the new ball bearing resp. the inner ring of aroller bearing has been heated-up
to ca. 80°C till 90°C, it must be mounted on the shaft very soon. If necessary, a short
pipe that fits onto the inner bearing ring can be used to push the bearing to its corret
position.
In no case, it is allowed to blow on the outer ring of the bearing.
Do not mount the end shield until the bearing has cooled down.

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8Bearing types
Motortype Poles Drive-end Non-drive-end
OMT2-56 2/4 6201 2RZ C3 6201 2RZ C3
OMT2-63 2/4 6201 2RZ C3 6201 2RZ C3
OMT2-71 2/4/6 6202 2RZ C3 6202 2RZ C3
OMT1/OMT2-80 2/4/6/8 6204 2RZ C3 6204 2RZ C3
OMT1/OMT2-90 2/4/6/8 6205 2RZ C3 6205 2RZ C3
OMT1/OMT2-100 2/4/6/8 6206 2RZ C3 6206 2RZ C3
OMT1/OMT2-112 2/4/6/8 6306 2RZ C3 6306 2RZ C3
OMT1/OMT2-132 2/4/6/8 6308 2RZ C3 6308 2RZ C3
OMT1-160 2/4/6/8 6309 2RZ C3 6309 2RZ C3
OMT1-180 2/4/6/8 6311 2RZ C3 6311 2RZ C3
OMT1-200 2/4/6/8 6312 2RZ C3 6312 2RZ C3
OMT1-225 2/4/6/8 6313 2RZ C3 6313 2RZ C3
OMT1-250 2/4/6/8 6314 2RZ C3 6314 2RZ C3
OMT1-280 2 6314 C3 6314 C3
OMT1-280 4/6/8 6317 C3 6317 C3
OMT1-315 2 6317 C3 6317 C3
OMT1-315 4/6/8 6319 C3 6319 C3
OMT1-355 2 6317 C3 6317 C3
OMT1-355 4/6/8 6322 C3 6322 C3
OMT1-400 2 6320 C3 6320 C3
OMT1-400 4/6/8 6326 C3 6326 C3
9Regrasing interval of bearings
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.

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Under normal load and environmental conditions the quality of the grease ensures
proper operation of the motor for about 20000 service hours with 2-pole design and
40000 service hours with multi pole design. 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 relubricating 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:
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.
Frame size
Motors with 2 poles
Motors with 4 and multi-poles
from 280 up to and incl. 400
2.000 hours
4.000 hours
10 Disposal
The applicable national regulations are to be observed with regard to disposal of the
machines.
It is furthermore to be ensured that oils and greases are collected for disposal in
accordance with the corresponding regulations on waste oils. They must not be
contaminated with solvents, cold cleaners and paint residues. The individual
materials should be segregated for recycling. The most important components are
grey cast iron (housing), steel (shaft, stator and rotor lamination, small parts),
aluminium (rotor), copper (windings) and plastics (insulation materials, such as
polyamide, polypropylene, etc.). electronic components such as circuit boards
(converter, sensors, etc.) are recycled separately.

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11 Motor spare part list / exploded view
Three-phase motor with squirrel-cage rotor
1 V-ring, oil seal DE 22 Mounting screw adoption plate
2 Mounting screw bearing cover DE 23 Lifting eye
3 Outside bearing cover DE 24 Circlip bearing DE
4 Grease-inlet for regrasing device DE 25 Bearing DE
5 Grease-outlet for regreasing device DE 26 Inside bearing cover DE
6 B5-shield DE 27 Key DE
7 B3-shield DE 28 Rotor
8 Mounting screw shield DE 29 Shaft
9 Motor housing 30 Inside bearing cover NDE
10 Gasket terminal box / motor housing 31 Bearing NDE
11 Terminal box 32 Non-drive-end shield
12 Mounting screw terminal box 33 Mounting screw shield NDE
13 Terminal board 34 Outside bearing cover NDE
14 Mounting screw terminal board 35 Mounting screw outside bearing cover DE
15 Connetor pin 36 V-ring, oil seal NDE
16 Nut for connector pin 37 Grease inlet for regreasing device NDE
17 Gasket terminal box / terminal box cover 38 Grease outlet for regreasing device NDE
18 Terminal box cover 39 Fan
19 Mounting screw terminal box cover 40 Circlip fan
20 Adoption plate for cable glands 41 Fan cover
21 Cable gland 42 Mounting screw fan cover