def faultratio(I, Ipickup, CTR=1):
    """
    Fault Multiple of Pickup (Ratio) Calculator.

    Evaluates the CTR-scaled pickup measured to pickup current ratio.

    M = meas / pickup

    Parameters
    ----------
    I:          float
                Measured Current in Amps
    Ipickup:    float
                Fault Current Pickup Setting (in Amps)
    CTR:        float, optional
                Current Transformer Ratio for relay,
                default=1

    Returns
    -------
    M:          float
                The measured-to-pickup ratio
    """
    M = I / (CTR * Ipickup)
    return M