Section 4 — Measurement Types and their Uses64Cross Channel PhasePhase analysis is an effective way to diagnose machine faults such asmisalignment, resonance, soft foot, and looseness. Phase analysis is alsouseful for distinguishing faults that look like imbalance but are actuallycaused by something else. For example, misalignment can show up at1X RPM, similar to imbalance. Knowledge of the phase relationships ofvarious machine faults will help confirm the existence of a specificmachine fault and help prevent misdiagnosis.Cross Channel Phase is a convenient method of taking phasemeasurements. It does NOT require the use of a tachometer or reflectivetape. Instead, phase is measured between two sensors.NOTE: When taking measurements, be aware of the direction eachsensor is facing. If you are measuring across the coupling in theaxial direction, you will probably turn the sensors in oppositedirections, thereby introducing an additional 180° phase change.Remember to take this into consideration when analyzing thephase measurements.
