For the testing of cage rotors, e.d.c. proposes the systems 7150W. These systems perform the automatic testing of cage rotors: various models are available on the base of the dimensions of the rotors to be tested (diameters from 20 to 400mm and stack height from 30 to 700mm – other ranges to be defined on request).
A really advanced measurement (R-TEST) allows the automatic identification both of mechanical faults and of the rotor bars. In particular, it’s possible to identify:
- Broken or Interrupted rotor bars
- Missing material in the rotor bar (incomplete injection)
- Poor connections or no connection to the end rings
- Changes in the consistency of the aluminium alloy and/or the iron core
- Short circuits between two or more rotor bars (soldering)
- Deviation of the rotor bar inclination angle relevant to the axis (skew)
- Not constant distance between bars and rotor axis
- Problems related to imperfect overlap of laminations
The rotor under test is placed in rotation. A special probe generates a magnetic field and acquires the signal generated by each bar when it is crossing the magnetic field. The acquired signal is processed by a special algorithm (R-TEST) enabling the separation from the signal information on each single defect. The most important characteristic of R-TEST is the possibility to associate to each specific defect a numerical value allowing an independent limit for each single fault to be set. In particular the test result RQF (ROTOR QUALIT FACTOR) indicates an overall rotor quality value.
The test can be performed on rotors with open or close bars, also before final turning.
Models available:
- 7150W standard model suitable to test rotors of small and medium dimensions (up to 90mm of diameter and up to 110mm of stack height)
- 7150WH model suitable to test rotors of medium and big dimensions (up to 400mm of diameter and up to 700mm of stack height)
- 7150WA model suitable for automatic lines. In this case it’s supplied only the acquisition system and the special probe, to be applied on the line
Special versions developed on the specific Customer’s requirements