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    Armature Windings

    Uploaded by

    Anna Marie Garbo

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd

    Armature Windings

    Uploaded by

    Anna Marie Garbo
    30 views19 pages

    Original Title

    2.-Armature-Windings

    Copyright

    © © All Rights Reserved

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    PDF, TXT or read online from Scribd

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    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    30 views19 pages

    Armature Windings

    Uploaded by

    Anna Marie Garbo

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    of 19

    The armature winding

    A). Lap winding- this winding forms a loop as it


    expands around the armature
     Progressive winding- winding expands from
    left to right (use + sign)

     Retrogressive winding- winding expands


    from right to left (use - sign
    THE ARMATURE WINDING, CONT.
    The armature winding, cont.
    B). Wave winding- this winding forms a wave as
    it expands around the armature
    Y= (Z ± 2m)/ P
    Y= (Yb+ Yf)/ 2
    Where:
    Y- average pitch (must be an integer)
    Z- total no. Of winding elements on
    the surface of the armature core
    M- multiplicity factor (1 for simplex,
    2 for duplex)
    P- no. Of poles
    Yb- back pitch
    Yf- front pitch
    The armature winding, cont.
    Types of Winding Elements per Slot
    Simplex 2
    Duplex 4
    Triplex 6
    Quadruplex 8

    Minimum Number of Elements or Conductors


    Number of Armature Current Paths
    per slot (If not specified in the problem)
    Z= (Elements/ slot)(Total no. of slot) a(Lap)= mP a(Wave) = 2m

    Number of Brushes (N) Number of Commutator Segments Coil Pitch (Ys)

    N(Lap)= P N(Wave)= 2 NC= Z/2 Ys= Coil span in slots/ Slots per pole
    The armature winding
    Sample problems:
    1. In a lap winding the front pitch is 17 and the back is 19. What is the average pitch?
    The armature winding
    2.The difference between the back pitch and the front pitch is 2. The front pitch is 21. If the
    winding is lap retrogressive, what is the back pitch?
    The armature winding, cont.
    Sample problems:

    3. If the armature of an 8-pole machine were wound with a simplex wave winding, how many
    parallel paths would there be?
    The armature winding, cont.
    4. A four-pole dc generator with lap winding has 48 slots and 4 elements per slot. How many coil
    does it have? Assume one conductor per coil side.
    The armature winding, cont.
    Sample problems
    5. A duplex lap wound, four-pole dc generator has 120 slots and four elements per slot. How
    many commutator segments are there?
    The armature winding, cont.
    Sample problems
    6. A 4-pole wave wound armature has 744 armature conductors in 62 slots. If the
    commutator has 186 segments, determine a). The coil span. 15 b). The no. Of conductors
    per coil.
    Generated emf equation
    Generated emf equation of a DC
    generator

    E= PNZΦ/ 60a
    Where:
    E- generated emf (volt)
    P- number of poles
    N- speed of armature core rotation (rpm)
    Z- total no. Of elements or conductors
    Φ- flux per pole (weber)
    A- no. Of armature current paths
    Generated emf equation, cont.
    If the flux is given in unit maxwell’s or lines,
    the above formula reduces to;

    E= (PNZΦ X / 60a) 10-8


    Where:
    E- generated emf (volt)
    P- number of poles
    N- speed of armature core rotation (rpm)
    Z- total no. Of elements or conductors
    Φ- flux per pole (maxwell)
    A- no. Of armature current paths
    Generated emf equation, cont.
    After the machine has been assembled, PZ and
    60a are constant;

    E= kNΦ E1/ E2= N1 Φ1 / N2 Φ2

    Where:
    E- generated emf (volt)
    K- proportionality constant
    N- speed of armature core rotation (rpm)
    Φ- flux per pole (maxwell)
    Subscript 1- for condition 1
    Subscript 2- for condition 2
    Generated emf equation, cont.
    Sample problems:
    1. A 4-pole dc generator with duplex lap windings has 48 slots and 4-elements per slot. The flux per
    pole is 2.5 x106 maxwells and it runs at 1500 rpm. What is the output voltage?
    Generated emf equation, cont.
    2. A 4-pole dc generator with simplex wave windings has 72 slots. The flux per pole is 2.88 x106 maxwells.
    What is the speed of the prime mover when the open circuit voltage of the generator is 120 volts?
    Generated emf equation, cont
    3. A dc generator is driven at a speed of 1000 rpm and generates 120 volts. Determine the
    generated emf if the speed is reduced to 900 rpm while the flux is increased by 25 percent.

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