Comparison of surface-mounted permanent magnet and interior-mounted permanent magnet starters for gas turbine engines electrical start

For starting gas turbine engines on gas pumping units, it is preferable to use an electrical method that is economical, simple, and environmentally friendly. This paper presents a comparison of two variants of a permanent-magnet synchronous starter with different inductor topologies. Both machines are designed with the same dimensions of the active part and the volume of permanent magnets. Permanent-magnet synchronous motors are compared in terms of torque, ripple torque, torque from the tooth harmonic in the gap, power efficiency, the ability to damp the armature reaction magnetic field and to counteract a demagnetization. The interior-mounted permanent-magnet starter has better efficiency; permanent-magnets are less susceptible to irreversible demagnetization in heavy load and emergency operation. The surface-mounted permanent-magnet starter has a higher density and less ripple torque, a more uniform distribution of magnetic flux density in the magnetic system elements.