On-line rotor flux measurements require the permanent installation of a flux probe on the stator to measure the rotor magnetic flux. Most machine OEM’s offer a flux probe which is attached to a stator winding wedge protruding into the airgap. Iris Power now offers an alternative probe, the TFProbe, which is a small, thin, flexible, printed circuit board transducer affixed to a tooth in the stator. The TFProbe measures the total airgap flux, rather than just the leakage flux as do older style probes. The TFProbe comes in two sizes, is easy to install, and requires no invasive drilling of stator wedges. Frequently, it can be installed with the rotor still in place!