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Which generator provides constant voltage for varying speed?
DC Generator
Alternator
Rosenberg generator
Synchronous generator
Rosenberg generator
The Rosenberg generator is a special type of cross-field DC generator designed to maintain a nearly constant voltage output despite significant variations in the input shaft speed. It is primarily used in applications like train lighting systems where the speed of the axle-driven generator fluctuates widely.
The Rosenberg generator is a special type of cross-field DC generator designed to maintain a nearly constant voltage output despite significant variations in the input shaft speed. It is primarily used in applications like train lighting systems where the speed of the axle-driven generator fluctuates widely.
EgтАЛ=KтЛЕ╬жтЛЕ╧Й тАФ The induced EMF formula where speed variations are compensated by ╬ж reduction.
VтЙИILтАЛтЛЕRaтАЛ тАФ Simplified voltage regulation logic in cross-field machines.
It operates on the principle of cross-field armature reaction. As the speed increases, the armature reaction creates a demagnetizing effect that automatically compensates for the increased induced EMF, keeping the terminal voltage stable. It utilizes a short-circuited brush axis to generate a cross-magnetizing flux that opposes the main excitation flux, resulting in a self-regulating voltage characteristic.
Specifically designed for constant output voltage at varying speeds.
Utilizes cross-field excitation to neutralize excess induced EMF.
Commonly used in railway carriage lighting and battery charging systems.
Inherently self-regulating without external voltage regulators.
No external voltage regulator required
Robust construction suitable for traction environments
Maintains stable output over wide speed range
Lower efficiency compared to modern solid-state converters
Requires complex brush assembly (cross-field design)
Significant sparking at commutator under certain conditions
Axle-driven train lighting systems
Early electric traction battery charging
Specialized constant current welding machines
Option A (DC Generator) typically requires a separate field regulator (like a carbon pile regulator) to maintain constant voltage.
Option B and D (Alternator/Synchronous generator) require frequency and voltage control systems (AVR) and are not inherently constant-voltage machines across high speed variations.
C is correct тАФ The Rosenberg generator uses armature reaction and cross-field effects to maintain a stable terminal voltage regardless of input speed.
Always relate the Rosenberg generator to the specific need for self-regulation in independent power sources like railway axles where shaft speed is directly coupled to vehicle velocity.