FIELD OF INVENTION:-
The invention relates to the construction of a framed 1190KW 3-phase AC
traction motor, for 9000 HP AC Electric Locomotive.
BACKGROUND AND PRIOR ART OF THE INVENTION:-
Indian Railways currently manufactures 6000 Horse Power AC Electric
locomotives for which design were received from ABB Switzerland through Transfer of
Technology (TOT). In these locomotives, hauling is done with 850 KW 3 phase AC
traction motors. These motors are operated with variable voltage variable frequency
supply from the converter-inverter bank housed inside locomotive. Electric locomotives
are used to haul passenger and freight traffic in the service of rail systems. Each
locomotive has 4 or 6 motors (depending BO-BO or CO-CO arrangement), which
produce the hauling power in the locomotive. In the existing 6000 HP AC electric
locomotives, frameless 850 KW traction motors are used for this purpose.
BHEL is regularly supplying frameless 850 KW 3-phase Traction motor which are
used in 6000 HP AC Electric locomotives application. These 6000 HP AC electric
locomotives are currently the most significant locomotives plying on the Indian
Railways.
In view of the ever-increasing freight loads and passenger requirements Indian
Railway are considering for development of more powerful 9000HP AC Electric
locomotives.
Now as load requirement has increased from 6000 HP to 9000 HP, new increased
power traction motor is required for 9000 HP locomotive.
To cater the motor requirement for 9000HP AC Electric locomotives BHEL has
proactively developed 1190KW Traction Motors. Type designation and BHEL

nomenclature of these motors is IM4506AZ. The developed traction motor is the most
powerful 3-phase traction motor yet developed, not only in BHEL but also in India
boasting of the highest ever Power to weight ratio. The developed motor is very
compact design and insulation of high temperature class i.e. Class 200 resulting in a
high power to weight ratio.
The developed motor is driven by 3-phase variable voltage variable frequency
supply from a converter-inverter set which receives its input from overhead
transmission lines through pantograph. Based on the supply from converter, the motor
rotates producing required torque at different speeds matching with the speed condition
of the locomotive so that the train runs smoothly picking up speed up to the desired
level.
OBJECTS OF THE INVENTION:-
The basic object of the invention is to design and develop High Horse Power
1190 kW, 3 phase AC traction motor, adaptable for 9000 HP AC Electric locomotives.
Another object of the invention is to design and develop a 3 phase AC, 1190 kW
traction motor used in 9000 HP Electric locomotives for Dedicated Freight Corridor
(DFC) application.
Yet another object of this invention is to increase reliability of operation and to
reduce abnormal sound and vibration from motor during service for higher capacity
locomotive.
A further object of this invention is to develop a motor that can produce the
required power (1190 KW) in same mounting envelop to suit the mounting of existing
6000 HP AC locomotive bogie.

SUMMARY OF THE INVENTION:-
Robust and sturdy framed construction of 1190 KW, 3-phase traction motor has
been developed for 9000 HP AC Electric locomotive in order to increase reliability of
operation due to abnormal sound and vibration experienced during service. In addition,
Drive End (DE) and Non Drive End (NDE) End shield modified to minimize sound and
vibration of machine during service.
The above-developed motor comprises a stator frame and stator core. Stator
core consists of sheet steel lamination, number of punched slots lamination of Inner
Diameter 450 mm, being configured along the length of the stator. The stator coils are
made up of rectangular copper wires covered with corona resistant film. The stator coils
have seven turns and are housed inside the slots to form the 3 phase star connected
winding, the supply terminals projecting out of the stator windings.
A rotor having a shaft and a number of sheet steel punching on the shaft
retained by end plates at both the ends. The rotor punchings accommodate rectangular
rotor Copper bars, the ends of the rotor bars being joined via a copper short circuit ring
to form a cage construction such that the rotor and the stator are operably compatible.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:-
Figure 1 Illustrates diagram of the newly developed 3-phase traction motor
displaying all the components
Figure 2 Illustrates torque-speed characteristics of the newly developed 3 phase
traction motor having desired torque.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION:-
The required performance of motor for 9000 HP locomotive has been achieved by
optimizing the electrical design through extensive experimentation, design calculations
and pre-assessment of the torque-speed characteristics. (Detail technical data of which
are annexed in Annexure-I).
The stator core, made of sheet steel laminations, are stacked together to form a
complete stator construction. The length of the laminated core, having punched slots,
have been set as 480 mm to achieve the mounting arrangement of same as existing
6000 HP AC Electric locomotive motor.
Stator coils made up of stator copper conductor covered with newly developed corona
resistance film are placed inside the slots in core and joined together in the form of a 3-
phase star connected winding. The stator coils, which have seven number of turns, are
consolidated to gather before insertion in to the slots.
As per the invention, the number of turns of the stator coil has been altered as
compared to exiting art to achieve the desired output from motor for 9000 HP loco.
The supply terminals of the stator winding are brought out for 3-phase electrical supply
to the motor.
The rotor of the motor has a shaft including a set of sheet steel punching which are
mounted and retained from both ends by end plates. The punching have slots in which
rotor bars of copper are inserted on each side of the rotor, the ends of rotor bars are
joined together by single shot brazing through a shorting ring of copper so that the
rotor bar and the shorting ring form a cage construction. Rotor construction has
accordingly been changed to establish a compatibly with the stator.

The roller suspension arrangement on an axle makes it possible for the motor to be
mounted on the existing axle without any change in the suspension bearing
arrangement.
Motor is mounted on the suspension tube by 8 nos. of bolt, which is fitted on the axle
using a set of bearings and associated bearing components.
The motor can be mounted on the existing bogie of 6000 HP locomotive without any
change in the suspension tube and the suspension bearing components.
Depending on the choice of the stator core, stator coil, rotor core and rotor
construction, the torque produced by the motor at different speeds have been
recorded.
The present invention proposes synchronization of these parameters to achieve the
desired torques at the starting including the continuous torque produced by the
developed motor during running condition.
This invention constitutes synchronizing of these parameters which have been
developed to achieve the desired starting torque required in service for use on 9000 HP
electric locomotives for freight application as illustrated in Fig 1.

Salient points of newly developed 3-phase AC Traction Motor for
9000 HP AC Electric locomotive are :
• Mounting arrangement of developed Traction Motor is same as existing 6000 HP
loco motor hence, same bogie can be used.
• Framed design in order to increase reliability of operation.
• Spigoting on complete periphery of DE and NDE side end shield to reduce
vibration and abnormal sound.
• Capsule design to increase productivity.
• Compact design for High Power to Weight ratio.
• Use of single shot brazing to increase productivity
• Suitable for high vibration levels.
• High permeability low loss stator and rotor punchings are used.
• Inorganic Class-200 insulation system.
• Vacuum Pressure Impregnation with solventless inorganic resin.
• Taper roller suspension bearing arrangement to make user friendly.
• Speed sensor provided for getting signals for control applications.
• Corona resistance copper used in stator coils for better performance.
• Machine confirms to IEC 60349-2.

1. A 3-phase AC, 1190KW, class 200, framed motor adaptable to 9000 HP AC
Electric Locomotives comprising;
a stator having frame (1) with stator core formed of electrical sheet steel
lamination;
a no. of punched slots of 480mm and above, configured along the length of the
stator;
stator coils having at least seven no. of turns placed inside the plurality of
punched slots to form 3-phase winding;
supply terminals in terminal box (5) projecting out of the stator windings;
a rotor having a shaft and plurality of electrical sheet steel punchings retained at
both ends of the shaft by end plate;
the punchings accommodate rotor bars, ends of which joined via shorting ring
forming a cage construction;
characterized by high power to weight ratio having roller suspension
arrangement on an axle for mounting the motor on existing axle without change
of the suspension bearing and mounting facilities.
2. The motor as claimed in claim 1, which is mounted on the suspension tube by 8
nos. of bolt, fitted on the axle using a set of bearings and associated bearing
components; motor mounted on the existing bogie of 6000 HP locomotive

without any change in the suspension tube and the suspension bearing
components.
3. A method of development and up-gradation of traction motor of claim 1, for
6000HP locomotives application to 9000HP locomotives application, wherein the
selection of stator core, stator coil, rotor core, rotor construction and the torque
produced by the motor at different speeds are based on prototype testing at
laboratory scale, reflected in data sheet (Annexure-I) and torque-speed curve
(Fig.2).
4. The method as claimed in claim 3, wherein spigoting on complete periphery of
Drive End (DE) and Non-Drive End (NDE) shield carried out reducing vibration
and abnormal sound.