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DC Motors & Generators (DC Motors (Produces Back EMF (Back EMF:…

- - - - Must have 2 to avoid irregular motion
    - - Supplies DC power
      - Always has reverse polarity with the stator brush
      - Torque action is always in the same direction
    - - Supplies a constant magnetic field
- - - - Yoke
        
        Protecting shield
        
        Provides mechanical support
        
        Cast Iron for small generators
        
        Cast steel or rolled steel for large generators
      - Pole Core
        
        spreads out flux
        
        reduces reluctance of magnetic path
        
        Supports field coils
      - Field Coils
        
        produce magnetic flux
      - Armature Core
        
        Path of Low Reluctance to Flux through armature
    - - Lap Winding
        
        No. of Brushes = No. of Parallel Paths = No. of Poles
        
        For High Current, Low Voltage Machines
      - Wave winding
        
        No of Parallel Path = 2
        
        For High Voltage, Low Current Machines
    - - Collects current from armature conductors
      - Converts AC to unidirectional current
    - - Collects current from commutator
- - - - Shunt Motor
        
        Low starting torque
        
        Able to run at constant speed regardless of load
    - - Series Motor
        
        Good starting torque
        
        Speed drops with load