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IPM or SPM for Wet Running Pump Applications

For a wet running pump application, a move from interior permanent magnet motor (IPM) with sintered neo magnet to surface mounted permanent magnet motor (SPM) is possible without increasing the motor size by using an anisotropic magnet (MQATM).

Difference between the two motors

Motor performance of same sized IPM and SPM

  • Wet running pump application, as the rotor comes in contact with the fluid, there is a need for corrosion protection on magnet
  • For sintered neo plate magnet based IPM motor:
    • Presence of overmolding on rotor ⟹ Increase in effective airgap ⟹ Permeance co-efficient decrease
      • The magnet operating point is Bm1
  • For PPS based injection molded (IM) MQATM based SPM motor:
    • No need for a PPS overmolding on the rotor ⟹ Reduction in effective airgap ⟹ Permeance co-efficient increase
      • The magnet operating point is Bm2
  • A SPM with IM MQATM magnet can meet the performance of a IPM with sintered neo magnet in the same envelope size.