Apparatus and method for material testing

A material testing apparatus, comprising:

• guide means;
• sample test means for holding a sample and applying a test force to the sample;
• a crosshead arranged to support at least a portion of the sample test means, wherein the crosshead is moveable about the guide means;
• electric clamping means configured to apply a releasable clamping force to the guide means to secure the crosshead at a location with respect to the guide means, wherein the electric clamping means is driven by an electric machine in a clamping configuration;
• and
• a controller arranged to:
• configure the electric clamping means into the clamping configuration;
• control the electric clamping means to apply the clamping force to the guide means;
• and
• configure the electric machine into a braking configuration, wherein in the braking configuration a winding of the electric machine is connected together with a low resistance connection.

A method of operating a material testing apparatus, wherein the material testing apparatus comprises:

• guide means,
• sample test means for holding a sample and applying a test force to the sample,
• a crosshead arranged to support at least a portion of the sample test means, wherein the crosshead is moveable about the guide means,
• crosshead drive means for moving the crosshead generally vertically about the guide means, wherein the crosshead drive means is driven by an electric machine in a driving configuration;
• and
• wherein the method comprises:
• configuring the electric machine into the driving configuration;
• controlling the crosshead drive means to move the crosshead generally vertically about the guide means;
• vertically moving the crosshead about the guide means using the electric machine;
• configuring the electric machine into a braking configuration, wherein in the braking configuration a winding of the electric machine is connected together with a low resistance connection.