Yet another growler test. This test uses a growler for inducing current flow through the rotor bars and iron filings for visualizing the resultant magnetic field. Very similar to the growler test utilizing magnetic viewing film, this test produces on paper a pattern that can be interpreted by a trained technician.
Introducing iron filings is a good way to contaminate a disassembled motor. In addition, as with the other growler test methods, the results of this test are entirely dependent on the knowledge and skill of the administering technician.