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A 35 kVA transformer supplies a load of 12 kW at a power factor of 0.45 lagging.
Find the percentage of full load the transformer is carrying. If additional unity power
factor loads are to be served with the same transformer, how many kW may be added
before the transformer is at full load

  • electrical -

    1. KVA*cosA = 12 KW,
    KVA*0.45 = 12,
    KVA = 26.7. = KVA used.
    %F.L. = (26.7/35) * 100% = 76.3.

    2. P = (35-26.7)cosA,
    P = 8.3*1 = 8.3 KW = Amt of unity P.F.
    Load that can be added.

    Alternate Method:
    1. %F.L. = (12/(35*0.45) * 100% = 76.2

    2. 12KW/0.45 + P/1 = 35 KVA,
    26.7 + P = 35,
    P = 35 - 26.7 = 8.3 KW. = Unity P.F.
    Load that can be added.

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