Study of the hysteresis curves of transformer stampings, ferrites and other magnetic materials of different shapes and determination of their energy losses
Study of the hysteresis curve as a function of the magnetic field. Determination of saturation, magnetization, remanence and coercivity of magnetic materials
Determination of saturation, magnetization, remanence and coercivity of magnetic materials
Theory In the conventional techniques of tracing the B-H loop, one has to wind a primary and a secondary coil on the specimen and experiment with it. This method is not convenient for a quick study of the shapes of B-H loops of different materials. The present technique can be used to study B-H loop by simply inserting the specimen in a magnetizing coil. It makes use of a specially designed integrated circuit probe to measure the flux density B. The current flowing through the magnetizing coil develops a potential difference across the resistance R which deflects the beam in the X-direction. The deflection is proportional to the magnetic field H which is given by:
where N is the no. of turns of the coil, R the resistance in series with the coil i.e. resistance between terminals G & H and L is the coil length in meters. VX is the voltage applied to the X-input of the CRO. The probe has a sensitivity of 5 mV per Gauss. Hence
where Vy is the voltage applied to the Y input of the CRO
Universal B-H Curve Tracer consists of the following parts:
Main Unit consisting of a variable A.C. supply (marked Va.c.), a resistor R in series with a potentiometer (P) and input terminal for the CRO.
Unit housing the I.C. probe with associated circuitry and One magnetizing coil (No. of turns = 300 of SWG26; length of the coil = 0.0323 m).
Samples: 5" nail, ferrite rod and transformer stampings.