Abstract: In view of the high energy consumption in the flotation process of polymetallic ore，the tra⁃ ditional asynchronous motor with belt wheel drive has the problems of long transmission chain，low trans⁃ mission efficiency and high operation and maintenance cost. Taking XCF-30 m3 flotation machine as the re⁃ search object，the energy-saving transformation test of permanent magnet synchronous motor was carried out. By combining theoretical analysis with industrial field measurement，the structure，operating efficien⁃ cy，power factor and temperature rise characteristics of asynchronous motor and permanent magnet motor are compared. Two transformation schemes of permanent magnet direct replacement and permanent magnet direct drive are set up and industrial tests are carried out. The results show that compared with the tradi⁃ tional asynchronous belt drive system，the comprehensive power saving rate of permanent magnet direct drive is 24.66%，and the power saving rate of permanent magnet direct drive can reach 31.56%. The power factor of the permanent magnet motor is increased to 0.96，the operating current and the temperature rise of the equipment are significantly reduced，and the operation stability of the equipment is improved. The direct drive cancels the belt drive，and the transmission loss is smaller and the maintenance cost is lower. The research confirms that the permanent magnet motor adapts to the complex working conditions of flota⁃ tion，which can provide engineering reference for the energy-saving transformation of mine flotation system and help the development of low-carbon and cost-reducing in the mineral processing industry.

Key words: polymetallic ore, flotation machine, permanent magnet synchronous motor, direct drive transmission, energy-saving transformation, energy efficiency improvement