MAGNET CHARACTERISATION

	INTRODUCTION
	OPEN + CLOSE LOOP EFFECT
	EDDY CURRENTS
	COMPARISON OF TECHNOLOGY USED IN MEASURING MAGNET CHARACTERISTICS

Comparison of Technologies used in Measuring Magnet Characteristics

In comparing the different processes, one basic principle remains constant and that is in each case the magnet being tested is driven around part of, or all, of its hysteresis loop via an applied external field. A detail of each type of technique is given later.

Pulsed Field Magnetometry (PFM)

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PFM offers the highest of possible applied fields and a very rapid open circuit measurement cycle. Measurement cycles of 4 seconds are possible full loop measurements are made without the need for seperate magnetising equipment. Hirst F2F processes remove eddy current effects.

VSM offers an pen circuit measuremtn of, usually small samples. If the VSM uses an electromagnet, only 2nd quadrant of part of the rare earth magnets can be measured.

Super conducting magnets can achieve higher fields but usually at the cost of slower speeds and the need for Cryogenic gases.

Permeaters often called Permagraphs of Hysterisographs offer a closed magnetic circuit measurement, but are limited to lower applied magnetic fields, and 2nd quadrant measurements of many magnetic materials.

To avoid eddy currents in the electromagnet, measurement cycles are slow.

The power requirements of this process are higher than others such as the PFM. This can be important where electricity supply costs are high.

Vibrating Sample Magnetometry (VSM)

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Permeameter Technology

Click here to view the comparision table which highlights at a glance the features of each technology used in the measurement of magnet sample characteristics

< Previous Eddy Currents

MAGNET CHARACTERISATION TECHNOLOGY COMPARISION TABLE

Click here to view the magnet characterisation comparison table.

The comparision table highlights at a glance the features of each technology used in the measurement of magnet sample characteristics

MAGNET CHARACTERISATION TECHNOLOGIES

Pulsed Field Magnetometry (PFM)

Pulsed Field Magnetometers apply a “pulse” of magnetic field to generate the applied magnetic field. This has the advantage that the field can be strong enough to saturate any magnetic material.

Vibrating Sample Magnetometry (VSM)

Vibrating Sample Magnetometers vibrate the sample as part of the measurement process. This provides the Fluxmeter element of the system with the dynamic component it requires to make the measurement. The applied field is changed so at each measurement point the field is static and hence no eddy currents to cause problems.

Permeameter Technology

Permeameters use a closed loop form of magnetic measurement.

MAGNET CHARACTERISATION TECHNOLOGY COMPARISION TABLE

The comparision table highlights at a glance the features of each technology used in the measurement of magnet sample characteristics