Introduction

For the VHM a non standard structure is required, capable of reacting against the high magnetic forces which, although varying with position, are always attractive.

Due to the rapid change of flux within the VHM, the main body of both the stator and the translator must be made of laminated steel, in order to minimise the formation of eddy currents. The support structure must compensate for the resulting weakness, particularly as the machine is likely to be quite large in a direction perpendicular to the plane of the laminations.

Figure 6.9 shows the VHM viewed along the axis of motion, so the translator moves in and out of the plain of the paper, with the simplified magnetic and structural forces included. In Figure 6.9A the translator is in the correct position: exactly in the middle of the two stator halves. The forces on the translator are equal and opposite, thus cancelling out, whereas the support structure still has to react against the closing force of the airgap. In Figure 6.9B, the translator has moved slightly upwards, giving a smaller airgap and hence bigger attraction to the upper stator compared to that of the lower half. The net force difference must be provided by the translator support, shown here as a set of bearings, in order to prevent the airgap closing.

Figure 6.9: Forces on VHM. (A), with translator in centre & (B). with uneven airgap
Renewable Energy Eco Friendly

Renewable Energy Eco Friendly

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable.

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