Compare Single phase 25 kV AC and 1500 V DC track electrification.

Compare Single phase 25 kV AC and 1500 V DC track electrification.
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1 Answer

Answer :

Points
Single phase 25 kV AC track Electrification
1500 V DC track electrification
Supply given to O/H condition
1-ph, 25KV, AC 50 Hz 
600/750V-Tromways 1500/3000V urban/suburban
Type of drive used
1-ph, AC series motor
DC series motor for tramways. DC compound motor
Weight of traction motor
1.5 times more than d.c. series motor.
1.5 times less than a.c series motor
Starting torque
Less starting torque than d.c series motor
High starting torque
Acceleration and retardation
Less than d.c series motor
High
Overload capacity
Less than d.c series motor
High
Method of speed control 
Simple and smooth
Limited, except chopper method
Maintenance cost of traction motor
More
Less
Starting Efficiency
More
Less
Ridding quality 
Less, better than d.c.
Smooth (Better)
Insulation cost 
High
Low
Cross section of conductor
Less
More
Design of supporting structure
light
Heavy
Distance between two substation
More
Less
No. of substation required for same track distance.
Less
More
Size (capacity) of traction substation
More
Less
Capital & maintenance cost of substation
Less
More
Cost track electrification for same track distance
Less
More
Applications
Main line services
Urban and suburban area
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