Contact resistance measurement on rotating machines
Contact resistance measurements are performed to detect loose connections as well as oxidized or damaged contact surfaces on machine pole connectors. These defects generate hot spots, which can lead to disconnection of the poles. DC current and DC voltage are measured at the same time for each pole connector of the rotor.
These measurements are compared to one another and to previous measurements to calculate the contact resistance. Poles with higher resistance values indicate possible loose or damaged connections.