In the field of electric motors is requested continuously innovation and efficiency. For this reason an important Italian company, manufacturer of electric motors for home appliances, involved us in the realizationf of 1 million of sintered ferrite rings, Halbach magnetized. The application? drain pump for dishwasher.
The complication of the project is due to the plastic rotor moulding joined with ferrite fragility. This process often casuse mirco-cracks on magnet surface. Those cracks, invisibiles to human eye, become evidents during rotation test and thermal resistance, where lots of temperature leap enlarge them.
We have therefore realized a sintered ferrite ring following requested dimensions: external diameter 37.65 mm, internal diameter 16 mm and high 15 mm. To reply to high efficiency request, magnetic powders correspond with IMF-9N quality, the highest grade for ferrite magnets. Features are: Br > 450-470 mT / HcB > 267-290 KA/m / Hcj > 275-298 KA/m / BH(max) > 38.8-42 KJ/m3.
The piece is Halbach 6 poles on OD preoriented. This allows to have a magnetic field on the external side of the ring, leaving the hole completely neutral, simplifing rotor moulding.
Thanks to our group’s experience, Compo Tech Co has been able to realize a ferrite magnet perfectly in compliance with customer’s request of dimensions and efficiency, but especially without cracks!
