A rotating asynchronous converter for connection of AC network with equal or different frequencies employs a first stator connected to a first AC network with a first frequency and a second stator connected to a second AC network with a second frequency, and a rotor which rotates in response to the first and second frequencies. An electrical bridge electrically couples a first electrochemical cell to a second electrochemical cell in series or parallel, and an electrical bridge is flexible and extends across the bridge portion of the first substrate layer. The gas enters the outer concentric flow path through a perforated sub set that is located below the packer. The present method may be successfully practiced at temperatures of less than 200\xb0 C. The present invention also provides compositions comprising such compounds, and methods for treating muscarinic receptor mediated diseases. The humidifier is particularly suitable for use in conjunction with solid polymer fuel cell systems.