Permanent magnet arrangement for an electrical machine
A permanent magnet arrangement for an electrical machine comprises a support structure for carrying magnetic flux and a pole assembly fixed to the support structure. The pole assembly comprises a magnet pole comprising at least one piece of permanent magnet material and a magnet carrier on which the magnet pole is mounted and which provides a magnetic flux path between the magnet pole and the support structure. The permanent magnet arrangement further comprises a sleeve containing the magnet pole and at least part of the magnet carrier. The magnet carrier is secured to the support structure to fix the pole assembly to the support structure and the sleeve is clamped to the support structure by the magnet carrier. A method for assembling the permanent magnet arrangement is also described.
1. A permanent magnet arrangement for an electrical machine, the permanent magnet arrangement comprising:
a support structure for carrying magnetic flux;
a pole assembly fixed to the support structure, the pole assembly comprising:
a magnet pole comprising at least one piece of permanent magnet material; and
a magnet carrier on which the magnet pole is mounted and which provides a magnetic flux path between the magnet pole and the support structure;
a sleeve containing the magnet pole and fully containing the magnet carrier;
wherein the magnet carrier is secured to the support structure to fix the pole assembly to the support structure.
2. A permanent magnet arrangement according to claim 1 , wherein the sleeve fully contains the magnet pole.
3. A permanent magnet arrangement according to claim 1 , wherein the permanent magnet arrangement includes a mechanical fixing that cooperates with the support structure and the magnet carrier to fix the pole assembly to the support structure.
4. A permanent magnet arrangement according to claim 3 , wherein the mechanical fixing extends through the sleeve to enable it to cooperate with the magnet carrier and thereby fix the pole assembly to the support structure.
5. A permanent magnet arrangement according to claim 1 , further including closure means for closing the ends of the sleeve.