Description

The magnetic field indicator shown in Fig. relies on the slots between the pie shaped segments to show the presence and the approximate direction of the external magnetic field. The “pie” field indicator is used with the magnetic particles applied across the copper face of the indicator (the slots are against the piece) simultaneously with the magnetizing force.
With an adequate amount of magnetizing current and proper particle application, the pie gauge will show indications in the same direction natural indications would appear.