Bldc motors in railway and metro

1. BLDC MOTORS IN RAILWAY AND METRO
Presented By :
Prakash.K
6th Sem, E&E Deportment,
STJ Polytechnic,
Harapanahalli.
Under the guidance of :
V.M.Hanagodi,
Lecturer of E&E Deportment.

2. INTRODUCTION:-
• Conventional dc motors are highly efficient and their
characteristics make them suitable for use as servomotors.
• However, their only drawback is that they need a commutator
and brushes which are subject to wear and require
maintenance.
• When the functions of commutator and brushes were
implemented by solid-state switches, maintenance-free motors
were realized.
• These motors are now known as brushless dc motors.

3. BLOCK DIAGRAM OF BLDC FANS:-

4. CONSTRUCTION OF BLDC FAN:-
• The construction of modern brushless motors is very similar to the ac motor,
known as the permanent magnet synchronous motor. Illustrates the structure
of a typical Three-phase brushless dc motor.
• The stator windings are similar to those in a polyphone Ac motor and the rotor
is composed of one or more permanent magnets. Brushless dc
• Motors are different from ac synchronous motors in that the former
incorporates some Means to detect the rotor position (or magnetic poles) to
produce signals to control the Electronic switches.
• The most common position/pole sensor is the Hall element, but some motors
use optical sensors.

5. BLDC FANS CAN BE CLASSIFIED AS :-
• 1) BLDC fans with sensor
• 2) ) BLDC fans without sensor

6. APPLICATIONS
• Brushless motors are more efficient at converting electricity into
mechanical power than brushed motors.
• This improvement is largely due to the brushless motor's velocity
being determined by the frequency at which the electricity is switched,
not the voltage.
• Additional gains are due to the absence of brushes, alleviating loss
due to friction.
• The enhanced efficiency is greatest in the no-load and low-load region
of the motor's performance curve.
• Under high mechanical loads, brushless motors and high-quality
brushed motors are comparable in efficiency.

7. CONSTRUCTION OF BLDC :
It consist of two parts mainly stator & rotor
Stator
• Stator is made up of silicon steel stampings with slots.
• The slots are accommodated armature windings.
• This winding is wound with specified no. of poles(even
number).
• This winding connected a dc supply through a power
electronic switching circuits ( inverter circuits) .

8. ROTOR
• Rotor is of permanent magnet no of poles on rotor is
same as that of stator
• Rotor shaft carries a RPS (Rotor position sensor) and it
provides information about the position of shaft at any
instant to the controller which sends signal to the
electronic commutator .
• The electronic commutator function is same as that of
mechanical commutator in DC motor

10. ADVANTAGES
• Increased Reliability & Efficiency
• Longer Life
• Elimination of Sparks from Commutator
• Reduced Friction
• Faster Rate of Voltage & Current

11. DISADVANTAGES
• Requires Complex Drive Circuitry
• Requires additional Sensors
• Higher Cost
• Some designs require manual labor (Hand
wound Stator Coils)

12. APPLICATIONS
• Consumer: Hard Drives, CD/DVD Drives, PC Cooling Fans,
toys, RC airplanes, air conditioners
• Medical: Artificial heart, Microscopes, centrifuges,
Arthroscopic surgical tools, Dental surgical tools and Organ
transport pump system.
• Vehicles: electronic power steering ,personal electric vehicles
• Airplanes: an electric self launching sailplane, flies with a
42kW DC/DC brushless motor and Li-Ion batteries and can
climb up to 3000m with fully charged cells

13. CONCLUSION
• Therefore, it can be adapted in speed control for
high-performance BLDC motor. Due to switched
mode operation of electric drives, the BLDC
motor line current contains harmonics
component and this causes torque ripple and
high electromagnetic interference problems.

14. THANK YOU …