def connect(self): 
        try:
            self.connection = pymongo.Connection(self.host, self.port)
            self.db = self.connection[self.name]
        except AutoReconnect:
            raise DatabaseException("It's not possible connect to the database")
def iqd_phasor(up, iqd, uqd, ax=0):
    """creates a phasor plot
    up: internal voltage
    iqd: current
    uqd: terminal voltage"""

    uxdq = (uqd[1]/np.sqrt(2), (uqd[0]/np.sqrt(2)-up))
    __phasor_plot(ax, up, (iqd[1]/np.sqrt(2), iqd[0]/np.sqrt(2)), uxdq)