Air-Gap Flux Probes
A flux probe test determines the existence of rotor winding shorted turns by measuring the magnetic flux produced by each coil in a generator's rotor. That measurement uses either a permanently-installed flux probe or a temporary flux probe that is installed through a cooling duct in the stator core. Generatortech’s Data Acquisition & Analysis Systems uses these probes to record the magnetic field close to the rotor surface and determines the location (pole and coil) and the number of shorts in each rotor coil. Testing is done while the generator is supplying power to the electrical grid.
Permanent Air-Gap Flux Probes
Permanent Air-Gap Flux Probes are custom designed and fabricated for each application.
Correct flux probe dimensional and sensitivity parameters are essential for obtaining signals that can be used for analysis. A variety of available models and construction materials are used to design and build the optimum flux probe for each generator.
Generatortech flux probe materials are impervious to the normally harsh environment within the generator and are expected to last for the life of the stator. We have probes that are over 35 years old functioning like new.
Temporary Air-Gap Flux Probes
Temporary Air-Gap Flux Probes are available for hydrogen and air-cooled machines.
While permanent probes must be installed while the rotor is removed from the stator core, there may be cases where critical shorted-turn conditions are experienced before a planned outage.
On many generators, it is possible to utilize a temporary flux probe. Temporary probes are inserted through a stator ventilation slot into the air-gap. For hydrogen-cooled generators, a ball valve assembly must be installed during an outage when the unit is degassed.
The data from a temp probe will provide the same definitive test results, thus allowing you to determine whether corrective action should be performed at the next outage.
Generatortech can help you evaluate the feasibility of installing the temporary test set-up.