def GetVoltWindow(voltage,windowSize,windowCtr):
    """ This function takes the voltage time series and retrieves a particular
        window based on the windowCtr parameter
            
            Parameters
            ---------
                voltage: numpy array of float (measurements,customers) time 
                    series voltage measurements
                windowSize: int scalar representing the desired window size
                windowCtr: int scalar representing which window to use

                
                
            Returns
            -------
                voltBatch: numpy array of float (windowSize, customers)
                    one window of the voltage time series
            """
                    
    start = windowCtr * windowSize
    end = windowSize * (windowCtr + 1)
    voltBatch = voltage[start:end,:]
    return voltBatch