The second diagram shows a machine with no excitation winding, but instead, a constant voltage is connected to the quadrature brushes. This produces a flux similar to the one produced by the rotation of the armature in the excitation flux in the first example. The operation of the machine is therefore very similar, with the output current rising until the flux it produces almost counteracts the flux generated by the applied voltage. Tustin has shown that the input and output power are the same, and so the machine transforms the constant-voltage input into a constant-current output. As with the metadyne generator, the Metadyne transformer can be partially compensated, and will continue to operate as a constant-current device until the compensation exceeds 97 per cent.