Page 201 - Electrician - TT (Volume 1)

ELECTRICIAN - CITS

Applications of dc shunt generators

• Constant voltage applications
• Battery charging

• Electroplating
• Welding purposes.
Conditions of build up of voltage
• Common conditions – Series and Shunt

• Residual magnetism
• Proper polarity of field winding to armature
• To aid increase in flux
• Proper Direction of Rotation
• Use flashing to get residual magnetism or
• Run the machine as DC Motor

Build up of voltage in shunt generator
• Start without load or light load
• High load at start will cause less field current and fail in build up
• Shunt field be less than “Critical Resistance”

• Load critical resistance.
• Resistance of shunt field beyond which shunt generator will fail to excite
• Critical speed- the minimum speed below which the shunt generator will fail to excite
Build up of voltage in series generator
• Compound have series and shunt field

• Long shunt or short shunt
• When series field aid shunt field flux – Cumulatively compounded
• When series field OPPOSE shunt field flux – Differentially compounded

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CITS : Power - Electrician & Wireman - Lesson 30-37