直流电机培训资料

maxon DC motor,Advantages of coreless DC motors The maxon DC motor Programs: RE, A-max, RE-max Construction and working principle Commutation systems Bearing systems,Dr. Urs Kafader, maxon motor ag, Sachseln, Schweiz,maxon DC motor: Variants,A-max-Motor with AlNiCo magnet precious metal brushes sintered sleeve bearing,RE-Motor with NdFeB magnet graphite brushes ball bearing,Coreless maxon DC motor: A-max,el. connections,flange,housing ( magn. return),commutator-plate,shaft,winding,precious metal brushes,permanent magnet,commutator,sintered sleeve bearing,Coreless maxon DC motor (RE 30),el. connections,self-supported winding,commutator,brushes,permanent magnet (in the center),housing (magn. return),Conventional DC motor,el. connections,housing (magn. return),winding,commutator,brush system,iron core,permanent magnet (at the periphery),Coreless winding systems,maxon,Faulhaber Portescap,Quelle: Portescap,Mauthe Kodak,corless (DC) slotless (EC),Advantage coreless: no cogging,no soft magnetic teeth to interact with the permanent magnet smooth running even at small speeds less vibration and noiseany rotor position can be controlled in a simple way no nonlinear control behaviour,Advantage coreless: no iron losses,no iron no iron losses constant magnetization high efficiency, up to above 90% low no load current, typical < 50 mA does not apply to EC motorsno saturation effects in the iron core Even at the highest currents the produced torque remains proportional to the motor current. stronger magnets = stronger motors,Advantage coreless: small inductance,less brush fire commutation: open and close a contact on an inductive load higher live expectancy less electromagnetic emissions easier to supress interferences: capacity between connections ferrite core at motor cablebut fast reaction of the current problems in combination with pulsed supply (choke needed),Advantage coreless: compact design,more efficient design of the magnetic circuit (even if the air gap is larger) more compact magnet in the center higher ratio of power to volumesmall rotor mass inertia hollow cylinder against full cylinder high dynamics typical acceleration times: 5 50 ms,S,F,RE,A,RE-max,maxon DC motor: Program,year 200019951990198519801970,A-max,rolled housing,magnet,plastic flange,design,NdFeB,AlNiCo,Ferrite,design and production,magnet,maxon DC motor: Programs,permanent magnet Ferrite AlNiCo NdFeB motor program F motor A-max, S, A RE, RE-max motor example 2130 GB A-max 19 GB RE 13 GB Dn/DM mNm/min-1 1150 1150 1250 assign. power 3 W 2.5 W 3 Wmotor size,diameter 30 mm 19 mm 13 mm length 33 mm 29 mm 34.5 mm cont. torque 3.3 mNm 4.4 mNm 3 mNm,23.3 cm3,4.6 cm3,8.2 cm3,Stator: the magnetic circuit,housing: magnetic return path made of steel (iron) guides magnetic field,air gap: the larger the air gap, the weaker the magnetic field,permanent magnet: produces magnetic field with north and south poles on opposite sides,Development of permanent magnets,NdFeB,SmCo,AlNiCo,SmFeN,steel,Ferrit,year,max. energy product (kJ/m3),max. energy product theoretical limit 960 kJ/m3 technically achievable ca. 720 kJ/m3,Permanent magnets,B T1.21.00.80.60.40.2,H kA/m 900 800 700 600 500 400 300 200 100,magnet Curie operation motor designtemperature Nd2Fe14B 310°C 110-170°C all, EC Sm2Co17 825°C 350°C SmCo5 720°C 250°C AlNiCo 850°C 550°C only coreless ferrite 450°C 250-350°C conventional,Construction of rotors,commutator plate,commutator,winding connections,winding,shaft,commut. plate,winding,commutator wire,epoxy,shaft with knurling,bondage,Winding: enameled wire,lacquer: plastic with solvant at enhanced temperature (130-150°C): plastic melts and connects neighbouring wires. pressing forms the body in narrow tolerances. outgassing of solvant: plastic hardens. baking of the winding.,copper wire,lacquer,insulation,copper core: good electrical conductor insulation: no short circuits,knitted maxon windingknitted winding for big motors with NdFeB magnet RE motors, EC motors thick walled windings,standard maxon winding,maxon winding: standard and knitted,Current flow in maxon winding,Force and torque production,rhombic current areas,magnetic field in air gap,force,magnetic return,force,Torque and current: torque constant,forces: force on current leading conductor in a magnetic field,torque: sum of all forces at the distance to the rotating axis,influencing parameters: geometry field density winding numbercurrent I,design,application,current direction towards flange,force,force,current direction towards brush,magnetic field,Speed and voltage: speed constant,winding rotates in air gap with inhomogenious magnetic field induced voltage Uind (back EMF) depending on geometry magnetic field density winding number speed nspeed constant kn inversely proportional to kM inversely proportional to generator constant (V/1000 rpm),