UMEB ASA User manual

OPERATION MANUAL
Three-phase squirrel cage induction motors in
flameproof enclosure Ex d IIC or Ex de IIC
type ASA and E2-ASA frame size 63 - 355
Bucharest, Romania
104A, Timisoara Blvd., district 6
Phone: [phone] ; fax : [phone]
e-mail: [email protected]

Three-phase squirrel cage induction motors in flameproof enclosure type ASA and E2-ASA
frame size 63 – 355

Three-phase squirrel cage induction motors in flameproof enclosure type ASA and E2-ASA
frame size 63 – 355
OPERATION MANUAL
Safety operating conditions for low voltage three phase asynchronous
squirrel cage motors according to EC Relevant Directives
When operating these motors have turning parts and hot surfaces. All the
operations during the transport, putting into operation and maintenance of
these motors have to be made by qualified and authorised persons.
Accidents and/or damages may occur in case of inadequate operations.
These low voltage motors are intended for industrial use and they are in
accordance with EN 60034 standard series. For their safe use in
hazardous locations, additional instructions given in this Operation Manual
have to be observed.
The manufacturer is not responsible for the accidents and damages risen
from non-observance of present instructions.
These motors do not contain hazardous substances with restricted use
according to the Directive 2002/95/EC (RoHS).
1. Denomination and using fields of motors
1.1 These operation instructions refer to low voltage three-phase
squirrel cage induction motors, type ASA and E2-ASA, suitable for
use in potentially explosive atmospheres, mainly in chemical and
petrochemical industry.
These motors are used in industrial applications and comply with the
following European Standards:
- EN 60034 (standard series) - Electrical machines
- EN 60034-6 – Rotating electrical machines – Part 6: Methods of
cooling (IC Code)
- EN 60034-7 – Rotating electrical machines – Part 7: Classification
of types of construction, mounting arrangements and terminal box
position (IM Code)
- EN 60034-14 – Rotating electrical machines – Part 14: Mechanical
vibration of certain machines with shafts heights 56 mm and higher
– Measurement, evaluation and limits of vibration severity
- EN 60079-0 - Explosive atmospheres - Part 0: Equipment –
General requirements
- EN 60079-1 - Explosive atmospheres - Part 1: Equipment
protection by flameproof enclosures “d”
- EN 60079-7 - Explosive atmospheres - Part 7: Equipment
protection by increased safety „e”

Three-phase squirrel cage induction motors in flameproof enclosure type ASA and E2-ASA
frame size 63 – 355
- IEC 60079-31 – Explosive atmospheres - Part 31: Equipment dust
ignition protection by enclosure „t”
- EN 60529 – Degrees of protection provided by enclosures (IP
Code)
- Directive 94/9/EC – Potentially explosive atmospheres (ATEX)
The motors type of protection is:
- Ex d IIC T5 Gb (alternatively Ex db IIC T5) or Ex t IIIC T1000C Db
(alternatively Ex tb IIIC T1000C) for the frame sizes 63-71 and
- Ex d IIC T4 Gb (alternatively Ex db IIC T4) and/or Ex d e IIC T4 Gb
(alternatively Ex db eb IIC T4) or Ex t IIIC T1250C Db (alternatively
Ex tb IIIC T1250C) for the frame sizes 80-355
They are designed to be used as:
- EPL Gb equipment and are allowed to operate in Zones 1 and Zones 2
where the risk of explosion is produced by a mixture of air with flammable
gases pertaining to Group IIC
and
- EPL Db equipment and are allowed to operate in Zones 21 and Zones 22
where the risk of explosion is produced by a mixture of air with flammable
dusts pertaining to Group IIIC
Cable entries are only suited for permanent wiring. The type of installation
shall provide for adequate strain relief.
1.1.1 Notation and symbolisation
The symbolisation of the motors type is made up of three groups of
letters and figures in the following order:
-group ASA and/or E2-ASA represents the motors series
denomination
-group of the mounting dimensions
-group of poles number
Examples of notation for a motor having the stator frame size 90L, 4
poles:
Motor type ASA 90L-4
Motor type E2-ASA 90L-4
1.2 The motors are intended to operate under temperate (N) climate
conditions, characterised by:
ambient temperature: -20 ... + 40 0C
relative humidity: 80% at + 20 0C
altitude: max. 1000 m (above sea level)

Three-phase squirrel cage induction motors in flameproof enclosure type ASA and E2-ASA
frame size 63 – 355
1.2.1 The environment may contain potential explosive mixtures made of air
and one of the substances pertaining to group C, temperature class T3, T4, T5,
according to EN 60079-0 or mixtures made of air and combustible dust
To avoid unpermissible surface temperatures, the possible dust layer upon the
machine surface must not exceed the maximum thickness of 5 mm.
On request, motors operating under tropical (up to +600C) or
cold (till -550C) climatic conditions are available. In the order
should be indicated the operation/storage temperature
1.3 The motors are not intended to operate under the following
conditions:
1.3.1 In mines where applications require ExdI motors
1.3.2 In places where abnormal vibrations or repeated mechanical shocks
at short time intervals are present (for example on vibrating
placements)
1.3.3 In areas containing nuclear radiation
1.3.4 In places exposed to thermal radiation coming from the surrounding
equipment
1.4 For the motors operating in areas where dust is present, care should
be taken to avoid the dust deposits with thickness higher than 5 mm
on the motor surface.
1.5 On demand, the manufacturer may build motors with other climatic
protections
2. Requirements and operating parameters
2.1 The motors are manufactured for three-phase networks with
symmetrical phase voltages and currents and the technical
requirements regarding the supply voltage are according to EN
60034 -1
The motors are suitable for three-phase mains power supply with
400 V rated line voltage and for 50 Hz rated frequency
The overtemperature of the windings for the rated duty, at the rated
parameters is in accordance with EN 60034 -1
In case the motors are fed at the limit values of the supply voltage
according to EN 60034 -1 zone A, the increasing of the winding
overtemperature by 10 K is permitted
On request, the motors can be manufactured for three-phase mains power
supply having other rated voltages up to 500 V, for 63-90 framesize motors
or 690 V for 100-355 motors. On request, motors for frequency of 60 Hz
are also available.

Three-phase squirrel cage induction motors in flameproof enclosure type ASA and E2-ASA
frame size 63 – 355
The motors can be fed from PWM frequency converters (VACON or
similar) according to the torque/speed characteristic M=f(Hz) given in
Annex 7 For that application the motors are equipped with direct
temperature control using the embedded PTC sensors (130 °C
 5 °C).
The thermistors must be connected to a thermistor circuit relay functioning
independently of any measurement or control devices required for
operation and that is dedicated to reliably trip off the supply of the motor
according to the requirements of the “Essential Health and Safety
Requirements” in Annex II, item 1.5.1 of the ATEX Directive 94/9/EC.
Emergency stop controls of safety devices must be fitted with restart
lockouts. A new start command may take effect on normal operation only
after the restart lockouts have been intentionally reset.
2.2 The motors are manufactured using insulation materials of class F
The windings insulating resistance should not be lower than:
o20 MOhm in cold condition
o3 MOhm in warm condition
2.3 The motors rated duty is the continuous duty S1, according to EN
60034 –1 par. 4.2.1. but frequency converter feeding according par.
2.1 is also allowed. The motors fed from frequency converters can
operate under S9 duty, according to EN 60034 –1 par. 4.2.9.
2.4 The normal degree of protection according to EN 60529 of the
motors operating in Zone 1 is IP55. On request, motors having IP
56, IP 65 or IP 66 protection degree are also available.
2.4.1 The protection degree of the motors operating in Zone 21 is IP65; on
request, IP66 protection degree is also available.
2.5 The method of cooling of the motors according to EN 60034 –6 is IC
411.
2.6 The motors could be manufactured in the following mounting
arrangements:
IM 1001, IM 1002, IM 2001, IM 3001, IM 1011, IM 3011 for the
frame sizes 80-355 and IM 3601 only for the frame sizes 63 -160,
according to EN 60034-7
The overall and mounting dimensions are indicated in:
- Annex 3 - Tables 5.1 and 5.2 for the constructive types IM 1001
- Annex 3 - Tables 6.1 and 6.2 for the constructive types IM 3001

Three-phase squirrel cage induction motors in flameproof enclosure type ASA and E2-ASA
frame size 63 – 355
2.7 The clearances in normal operation between the external fan and its
hood, the motor shields and their fasteners, according to EN 60079-
0 par. 17.4 should be at least 1/100 from the maximum diameter of
the fan but not less than 1 mm.
Mounting types with the shaft end facing downwards are to be
provided with a cover (canopy) preventing foreign bodies from falling
into the ventilation openings.
Ventilation must not be obstructed and the outgoing air –also
including that from the adjacent units - must not be directly sucked in
again.
The clearances between the NDE-side fan cowl and adjacent solid
obstacles must not be lower than one quarter of the air inlet
diameter (see following fig.)
The distance between the complete motor housing and any solid
obstacle shall not be smaller than
Gas / vapour
subgroup
Minimum distance
[mm]
II A 10
II B 30
II C 40
2.8 The terminal boxes are dimensioned for connecting armoured
copper cables.
The terminal boxes are fitted with:
1 terminal plate with 6 terminals for the frame size 63-71

Three-phase squirrel cage induction motors in flameproof enclosure type ASA and E2-ASA
frame size 63 – 355
3 or 6 bushings and optionally with one BT18 bushing for
additional protective devices for the frame sizes 80 – 355.
1 or 2 metric (or other standard thread) cable entries for the
frame sizes 63–132
2 metric (or other standard thread) cable entries for the frame
sizes 160 – 355
Optionally, the terminal boxes could be provided with an additional
cable entry having the size IPE/PG 16 or M20x1.5 for the frame size
63-355.
2.9 The motors type of protection is:
flameproof enclosure „d” for the frame size 63-355
flameproof enclosure „d” having an increased safety „e” as an
option for the terminal boxes in case of 80 – 355 framesize
motors
protection by enclosure „tb” for the frame size 63-355
2.10 The motors are designed for „IIC” gases group, according to EN
60079-0, being also suitable for applications that require group „II
A” and „IIB” motors.
They are intended for the use as EPL Gb equipment.
2.10.1 The motors designed „tb” are suitable for applications in Zone 21,
according to EN 61241-14, being also suitable for applications in Zone 22.
They are intended for the use as EPL Db equipment.
2.11 The temperature class T3, T4, T5 indicates the maximum surface
temperature of the enclosure and is confirmed by the EC-type-
Examination Certificate.
2.11.1 T1000C and T1250C indicates the maximum surface temperature of
the motors wich operate in explosive dust atmosphere and is confirmed
by the EC-type-Examination Certificate
3. Product description
The flameproof enclosure consists of:
a. cast iron or welded steel housing
b. cast iron shields
c. cast iron terminal box
d. cast iron terminal box cover
To provide the flameproof enclosure with necessary mechanical features,
only screws of the strength class minimum 8.8 shall be used as assembling
elements.
The motors are equipped with rolling-contact bearings.

Three-phase squirrel cage induction motors in flameproof enclosure type ASA and E2-ASA
frame size 63 – 355
The motors up to frame size 250 are equipped with prelubricated bearings;
regreasable bearings are used for motors with frame sizes 280 and 315.
The bearing selection is given in table 1.
The bearings are not dimensioned to support external axial forces.
The maximum permissible radial forces on the shaft end for minimum
20.000 hours bearings life, are given in Annex 4
Table 1
Drive end Non drive end
Frame size
2p = 2 2p = 4, 6, 8 2p = 2, 4, 6, 8
63 6202 2Z P6 6202 2Z P6
71 6203 2Z P6 6203 2Z P6
80 6304 2Z P6 6304 2Z P6
90 6305 2Z P6 6305 2Z P6
100 6306 2Z P6 6306 2Z P6
112 6307 2Z P6 6307 2Z P6
132 6308 2Z P6 6308 2Z P6
160 6310 2Z P6 6310 2Z P6
180 6311 2Z P6 6311 2Z P6
200 6312 2Z P6 6312 2Z P6
225 6313 2Z P6 6313 2Z P6
250 6313 2Z P6 6314 2Z P6 6313 2Z P6
280 6314 P6 6316 P6 6314 P6
315 6315 P6 6317 P6 6315 P6
315M/L 6316 P6 6319 P6 6316 P6 6319 P6
355 6319 P6 6322 P6 6319 P6 6322 P6
The type of main cable entries and minimum supply cable diameter are
given in the tables below:
Table 2.1
Frame size
Entry
thread
size
Size
Dxd
Minimum admissible
supply cable diameter
[mm]
Tightening
torque
limits
[Nm]
63
71
80
90
IPE/PG
16 20x11 10.5 20
26x10 9.5
100 IPE/PG
21 26x13 12.5
27

Three-phase squirrel cage induction motors in flameproof enclosure type ASA and E2-ASA
frame size 63 – 355
Frame size
Entry
thread
size
Size
Dxd
Minimum admissible
supply cable diameter
[mm]
Tightening
torque
limits
[Nm]
26x16 15.5
112 26x19 18.5
132 35x18 17.4
160 35x21 20.4
35x24 23.4
180
IPE/PG
29
35x27 26.4
27
45x24 23.4
200 45x27 26.4
45x30 29
225
IPE/PG
36
45x33 32
54
52x30 29
250 52x33 32
52x36 35
280
IPE/PG
42
52x39 38
107
57x36 35
57x39 38
57x42 41
315S/M and
315M/L
IPE/PG
48
57x45 44
120
Optional entry for
prot. devices
IPE/PG
16 20x11 10.5 20
Table 2.2
Frame size Entry
thread size
Size
Dxd
Minimum admissible
supply cable
diameter
[mm]
Tightening
torque limits
[Nm]
63
71
80
90
M25x1.5 23x11 10.5 20
30x10 9.5
100 30x13 12.5
30x16 15.5
112
M32x1.5
30x19 18.5
27

Three-phase squirrel cage induction motors in flameproof enclosure type ASA and E2-ASA
frame size 63 – 355
Frame size Entry
thread size
Size
Dxd
Minimum admissible
supply cable
diameter
[mm]
Tightening
torque limits
[Nm]
30x16 15.5
30x18 17.4
132 M32x1.5
30x21 20.4
38x18 17.4
160
38x21 20.4
38x24 23.4
180
M40x1.5
38x27 26.4
54
48x24 23.4
200-225 48x27 26.4
225-250 48x30 29
250
M50x1.5
48x36 35
107
61x30 29
280 61x36 35
61x42 41
315
355
M63x1.5
61x45 44
120
Optional for
prot. dev. M20x1.5 18x11 10.5 20
NOTE: Maximum diameter of the supply cable is to be considered as the
maximum diameter of the cable that can be introduced by hand, into the
sealing ring of the cable entry.
On request, the terminal box with an additional IPE/PG 16 or M20x1.5
cable entry is also available.
The cable entries are only suited for permanent wiring.
4. Measurement and control devices
The following measurement and control devices are needed when
commissioning or maintainig the motors:
megohmmeter of 1000 V, to measure the insulation resistance
voltmeter to check the supply voltage
ammeter to measure the phase currents
tachometer to measure the speed

Three-phase squirrel cage induction motors in flameproof enclosure type ASA and E2-ASA
frame size 63 – 355
5. Special tools and spare parts
In order to mounting and dismounting the motors wrench assortments (hex
key wrenches, wrenches for hexagon screws) and bearing
mounting/dismounting appropriate tools are to be used. The tools are not
included in the motors delivery inventory.
The spare parts are listed in Annex 7 and are delivered at client’s request.
Only original spare parts are allowed to be used for repairing of the ASA
flameproof motors.
6. Preparing for commissioning
6.1 Unpacking
-The motors that are not commissioned immediately after delivery
shall be stored in their initial packing, in dry rooms, away from
freezing and flooding, free from vibrations, dust, oxide vapours or
corrosive substances.
The removing of the packing should be carried out in clean rooms, at
ambient temperature of minimum +15 °C and maximum 70% relative
humidity.
The integrity of mounting surfaces with the driven installation:
shaft end
flange shoulder (if case is)
feet and fixing holes (if case is)
need to be checked.
If rust appeared on these surfaces, they will be cleaned with smooth cloth
and thinner, then a thin film of anti-rust grease according to the technical
quality conditions –
Annex 6, will be applied.
6.2 Preliminary checking before mounting
Before mounting will be checked:
6.2.1 whether the shaft rotates easily by mere hand rotating
6.2.2 the protective painting and coating condition

Three-phase squirrel cage induction motors in flameproof enclosure type ASA and E2-ASA
frame size 63 – 355
6.2.3 the insulation resistance; if the value of winding insulation resistance
is below
20 MΩ, the motor should be dried. The drying could be carried out:
introducing the motor in a drying kiln, for several hours at
maximum temperature of 80 °C
blowing the motor with an air stream having maximum
temperature of 80 °C
running the motor at no load (if the actual conditions allow)
The drying is finished when the winding insulation resistance keeps
constant at a value no lower than 20 MΩ.
6.2.4 Prolonged storage periods reduce the usefull life of the bearing
grease. If stored for more than one year the condition of the grease
must be checked enabling the motor to no-load run.
If abnormal noise, local heat or locking symptoms arise, then:
- prelubricated bearings must be replaced
- in case of regreasable bearings: the old grease must be removed
and fresh grease UNIREX N2, UM185Li3, Shell Alvania R3, or
similar (the grease type is given on the motor rating plate) should be
used to relubricate them. If the troubles persist, the bearings should
be replaced with new ones.
6.3 Preparations before mounting
The mounting location should:
enable easy acces to the motor terminal box
not obstruct the motor ventilation
be away from heating sources
enable the access of surveillance and maintenance personnel
In order to remove dust or other solid particles from the outer surface,
before mounting the motor should be blown off with high pressure dry air.
The data on the motor rating plate should be checked to meet the driven
equipment requirements as to:
rated output
rated speed
voltage and frequency
connection
hazardous area classification
6.4 Coupling
Depending on the driven mechanism and operation conditions there are
several ways to transmit the motor torque.

Three-phase squirrel cage induction motors in flameproof enclosure type ASA and E2-ASA
frame size 63 – 355
Be aware for adherence to Directive 94/9/EC also for the transmitting
devices. They have to be ATEX certified too.
6.4.1 Flexible coupling
It is the most frequent type of coupling, but special attention should
be paid to accurate alignment of the motor with the driven
equipment
Any failure in correct alignment entails vibrations, noisy functioning,
bearing additional strains and eventually bearings and winding
damaging.
6.4.2 Belt coupling
Only those belts may be used which do not electrostatically charge.
Motor is mounted on slide bars ensuring belt tensioning which may
subsequently be corrected.
Exaggerated belt tensioning leads to high radial loads on bearings
and shaft end while insufficient tensioning leads to belt „stroke” and
the rotor torque transmission is no longer possible.
It should be observed that for the mounting arrangements IMB6,
IMB7, IMB8, IMV5 and IMV6 the belt tension is only permitted to act
parallel to the mounting surface or towards the mounting surface
and when mounted, both feet (in case of foot-mounting
arrangements) must be secured and supported.
6.4.3 Gear coupling
In this case the shafts of the motor and driven equipment must be
parallel and the tooth gears must function accurately in order to
prevent bearings overloads and premature wear.
Before mounting the coupling, driving pulley or toothed gear a thin
layer of grease will be applied on the motor shaft end ensuring thus
easy mounting of the driving parts.
The transmission elements should be mounted with the press. They
should be pressed up to the shaft end collar.
6.5 Electrical connection
The rules regarding electrical installations in hazardous atmospheres are to
be strictly observed. All mounting and installation works must be performed
by experienced personnel in accordance with EN 60079-14 and local
authority regulations.

Three-phase squirrel cage induction motors in flameproof enclosure type ASA and E2-ASA
frame size 63 – 355
And they must be carried out on standstill machine, isolated and secured
against reconnection only. Check safe isolation from supply !
Line cables and their installation shall adhere to EN 60079-14.
The motors are provided with six terminals and they may be started either
by network direct connection or by means of star-delta switch or another
starting device limitting the motor starting current. The star-delta starting is
only possible in case of delta working connection.
Warning ! When supplying the motors with increased safety „e” terminal
box, marked accordingly, special care must be given to:
Correct connection of the cables to the terminals by means of
connection devices (see connection diagrams Annex 1), so that the
creepage and clearance distances are closely observed.
Tightening to torque values indicated in paragraph 6.8.2.1 of the electric
connecting devices
Correct mounting of all cable entry devices as well as the terminal box
cover with a view to preserve the motor protection degree.
Warning ! When supplying the motors with flameproof „d” terminal box,
special care must be given to:
Tightening to torque values given under paragraph 6.8.2.2 of the screws
fixing the terminal box cover
Tightening to torque values indicated in paragraph 6.8.2.1 of the electric
connecting devices
Correct mounting of all cable entry devices as well as screwing the
presser according to torque values indicated in tables 2.1 and 2.2.
To connect the supplying cables to the motor terminals, the user should:
take off the cover of the terminal box using an appropriate hex key
wrench
unscrew the presser (thread adapter) using a hexagon wrench, then
take off the compression ring, the wall and the sealing gasket
introduce the supplying cable through the presser, compression ring and
sealing gasket
introduce the cable into the terminal box
put into correct position the sealing gasket, compression ring and the
presser.
When screwing the presser it presses on the sealing gasket and this one,
at its turn, on the cable sheath ensuring thus the sealing of the terminal box
connect the supply cable to the motor terminals;
before connecting the lead to the earth terminal in the terminal box,
clean to white metal the contact surfaces and cover them with a thin layer
of conductible grease

Three-phase squirrel cage induction motors in flameproof enclosure type ASA and E2-ASA
frame size 63 – 355
close the terminal box mounting the cover
Warning ! The terminal boxes must always be tightly closed during motor
operation.
6.6 Connection to earth terminal
Is made by means of low resistivity multicore cable in accordance with
labor safety rules. Apropriate conventional symbols indicate the location of
the earth terminals on the housing.
To connect the protection lead to the earth terminal, the user should take
off the screw and the washers, clean to white metal the contact surface,
apply a thin layer of conductible grease (e.g. copper grease) then connect
the lead fastening the screw.
6.7 Overload protection
The user should protect the motors against overload currents exceeding
the rated curent values indicated on the rating plate.
According to EN 60079-14 chapter 7, the overload protective device shall
be :
- a current-dependent, time lag protective device monitoring all three
phases, set at not more than the rated current of the machine, which will
operate in 2 h or less at 1,20 times the set current and will not operate
within 2 h at 1,05 times the set current
- another equivalent device
6.8 Checking the mounting accuracy
Before connecting the motor to the supply network it is recommended to
check whether:
6.8.1 All fixing parts are tightened
6.8.2 Coupling with the driven equipment is correct
All screws and electric contact nuts are tightened and earth connection is
correctly made. The folowing torque limits (screw and nut) should not be
exceeded
WARNING! Screws which become unusable have to be replaced by new
ones of the same strength class (min.8.8) and type

Three-phase squirrel cage induction motors in flameproof enclosure type ASA and E2-ASA
frame size 63 – 355
6.8.2.1 Screwed joints for electrical connections
Thread Tightening torque
[Nm]
M4 1.2
M5 2.0
M6 3.0
M8 6.0
M10 10
M12 15.5
M16 30
6.8.2.2 Screwed joints strength class 8.8 only in components with
higher strength (e.g. grey cast iron, steel)
Thread Tightening torque
[Nm]
M4 2.3
M5 4.5
M6 7.9
M8 19
M10 38
M12 68
M14 105
M16 160
6.8.3 The access to the electrical parts is prevented
6.8.4 All switching devices are put in position „0” or „off”
6.8.5 The free access of cooling air is not obstructed (the cowl’s holes are
not obturated)
6.8.6 The rules regarding electrical installations in hazardous
atmospheres are strictly observed
If all above conditions are observed then a motor test start is to be
performed with a view to check the rotation direction and if there are no
vibrations or abnormal noise.
If the rotation direction is not the required one, the motor is to be
disconnected and the direction of rotation can be reversed by changing the
position of two mains conductors on the terminal board.

Three-phase squirrel cage induction motors in flameproof enclosure type ASA and E2-ASA
frame size 63 – 355
If a new test start proves that the motor works properly than it is ready to
operation.
6.9 Stoppages
If the motors remain out of service for a long period of time (more than a
year), anti-corrosion, mothballing and drying measures it is recommended
to be taken.
7. Main possible faults and remedies
Table 3
No. Fault Possible causes Remedy
a. Locked bearings Replace the bearings
b. Locked bearings
Wash the bearings and
regrease them with
recommended grease
1.
The shaft does
not turn when
manually rotated c. Fan cover deformed
causing rubbing by the
fan
Repair or replace the fan
cover
a. Two phase supply
Check the connexions to
the terminal box, to the
mains as well as the supply
cable
b. Wrong winding
connection (in case of 6
terminal ends)
Check the connections to
the terminal box
2. No loaded motor
fails to start
c. Locked rotor Check whether the driven
mechanism is not jammed
a.See the causes and remedies under item 2
b. Mains voltage too low Check connection at the
mains
3. The motor does
not start in load c. Motor load is higher
than the rated value
Compare data on the rating
plate
a. Mains voltage too low Check connection at the
mains
b. Motor load is higher
than the rated value
Observe data on the rating
plate
4. High decrease in
speed
c. The supply cable
insufficiently sized (too
high voltage drop on
cable)
Use a supply cable
correctly sized

Three-phase squirrel cage induction motors in flameproof enclosure type ASA and E2-ASA
frame size 63 – 355
No. Fault Possible causes Remedy
d. Mains low frequency Check connection at the
mains
a. Faulty contact in a
connection point of the
supply circuit
Check the electric circuit
5. Uneven phase
currents
b. Shortcircuit in the
motor winding Re-wind the stator
a. Faulty coupling Check the coupling
b. Damaged bearings Replace the bearings
6.
Noise and
vibrations in the
motor c. Unbalanced rotor Balance the rotor
a. See faults and remedies under item 2.
b. Shortcircuit in the
motor winding Re-wind the stator
7.
Protective
devices
disconnect the
motor at start c. Wrongly adjusted
protection
Adjust correctly the
protection
a. Motor non-operation
too long
b. Environment moisture
above normal limits
8. Low insulation
resistance
c. Ingression of water
inside the motor
The motor winding should
be dried according to the
methods
given in 6.2.3
a. Cowl’s holes are
covered
Enable free access of
cooling air
b. Heavy amount of dust
between the cooling ribs
of the housing or another
dregs
Clean the housing
removing the dust
c. Fan blades broken Replace the fan
9. Over heating of
the motor
d. Over-current Adjust correctly the
overload protection device
8. Motor dismounting
The ASA type motors are flameproof motors, and their joints should meet
special requirements so that flameproof character is observed.
Warning ! Only workshops authorised to carry out maintaining and
repairing works of electrical equipment in flammable atmospheres are
allowed to mount or dismount ASA type motors.
Do not dismount when the motors are energized

Three-phase squirrel cage induction motors in flameproof enclosure type ASA and E2-ASA
frame size 63 – 355
8.1 Dismounting of the terminal box (see fig. 1 and 2)
dismount the terminal box cover (1) enabling thus the access to the
screws fixing the supply cable to the terminals (bushings). Use a proper wrench to
unscrew the hexagon socket head cap screws. To remove the terminal box cover
tap it alternatively with a wooden, plastic or rubber hammer avoiding to lock it.
using a hexagon wrench unscrew the presser (2) and take off the supply
cable from the terminal box
remove the terminal box (3) using an adequate device
unscrew the nuts (4) at the bottom of the terminals, loosing the wire
terminals
the bushings can be removed using a socket wrench after the terminal
box is dismounted
8.2 Dismounting of the fan (see fig 1 and 2)
remove the fan cowl (6); in case of motors with regreasable bearings,
prior to removing the cowl, the lubricating devices (5) must be taken off
remove the safety ring (7)
using an adequate device remove the fan (8) from the shaft
8.3 Dismounting of the rotor (see fig 1 and 2)
dismounting should be made observing the operation succession given in
fig. 1 and 2
using appropriate dismounting devices (mechanical presses with
threaded rods and central screw), the shields should be pulled-off from the
housing. When pulling the shields, the pressure should be applied gently,
evenly, to avoid the damaging of the contact surfaces forming flame-proof
joints or the bearings.
8.4 Dismounting of the bearings
Mechanical jaw pullers or other proper dismounting tools should be used to
remove the bearings from the shaft or from the shields
8.5 Re-mounting of the motor
It should be done in reverse order of the dismounting operations (see fig. 1
and 2)
Before mounting, the surfaces forming flameproof joints between stator-
shields, stator-terminal box, terminal box-terminal cover and the thread joints
of the cable entries, shall be protected with a thin layer of grease having the
technical parameters according to Annex 4 or other similar grease.