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How to Troubleshoot VSM

The magnetic properties of materials are normally characterized by applying an external magnetic field and measuring how the intrinsic magnetization of the material changes. This process is often carried out by using a vibrating sample magnetometer (VSM). A VSM consists of a sample rod that is placed in between inductive coils. As the magnetic sample vibrates up and down, an electrical current that is proportional to the sample magnetization is induced in the coils. VSM problems can often be resolved using some simple laboratory equipment.

Things You'll Need

Digital multimeter
Gauss meter

Instructions

- 1
  Start the VSM field sweep. During this process, an external magnetic field is generated by an electromagnet. This external magnetic field modifies the sample magnetization, which in turn is measured by a series of inductive coils. Switch on the Gauss meter and place the probe in between the pole pieces of the electromagnet. If the display shows the field is sweeping, then the electromagnet has no problems. If the field is not sweeping, then there is a problem with the electromagnet or its power supply.
- 2
  Switch the VSM off. Switch on the multimeter and set it into resistance mode. Place the multimeter measurement probes onto the terminals of the inductive coils. Check the measured resistance against the coil specifications provided by the manufacturer. Generally, the resistance should be low and below 100 Ohms. Anything higher indicates a break in the coil.
- 3
  Start the VSM field sweep. Check to ensure that the sample rod is vibrating. There are a number of ways to do this. It can be done by visual inspection or by feeling the vibration on the stick. Alternatively, the VSM software should have an indicator that shows the vibration frequency. If the sample rod is not vibrating, then there may be a problem with the VSM motor output or with the motor itself.

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