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Which is not frequancy of single phase low frequancy system
50HZ
25HZ
16(2/3) HZ 16 (2/3)HZ
B AND C B and C
50HZ
Standard power frequency in India is 50 Hz, which is categorized as standard industrial power frequency, not a low frequency used in traction. Single-phase low-frequency systems (typically 16.67 Hz or 25 Hz) are specialized railway electrification systems designed to improve the performance of AC series motors and reduce commutation issues.
Standard power frequency in India is 50 Hz, which is categorized as standard industrial power frequency, not a low frequency used in traction. Single-phase low-frequency systems (typically 16.67 Hz or 25 Hz) are specialized railway electrification systems designed to improve the performance of AC series motors and reduce commutation issues.
XLтАЛ=2╧АfL тАФ Inductive reactance formula showing direct proportionality between frequency and reactance
f=T1тАЛ тАФ Basic frequency-time period relationship
Low-frequency traction systems are employed because at lower frequencies, the inductive reactance (XLтАЛ=2╧АfL) of the traction motor is reduced. This allows for better torque-speed characteristics and minimizes sparking at the commutator brushes of AC series motors (Universal motors) used in older electric locomotives.
Industrial frequency is 50 Hz or 60 Hz.
Low frequency systems (16.67 Hz or 25 Hz) are used for AC traction.
Reduced frequency leads to smaller commutation problems in AC motors.
50 Hz is standard supply, not a 'low frequency' traction variant.
Better commutation in AC series motors
Reduced inductive voltage drop
Improved power factor
Requires bulky transformers
Needs separate frequency conversion infrastructure
Higher weight of rolling stock
European Railway Electrification (e.g., Germany, Switzerland, Sweden)
Legacy AC Traction systems
The 16.67 Hz frequency is exactly 50/3 Hz.
Option D is valid as a descriptor because both 25 Hz and 16.67 Hz are recognized low-frequency traction standards.
A is correct тАФ 50 Hz is the standard power frequency and does not fall under the category of low-frequency traction systems.
In traction engineering, remember that frequency selection is a trade-off between motor performance (favors low frequency) and infrastructure/transformer size (favors high frequency).