Basic structure and working principle of centrifuge DC motor
1. The main magnetic pole set up the main magnetic field (N and S alternately list).
A, main pole core magnetic circuit, composed of 1.0~1.5mm thick steel plate.
B, excitation winding circuit, winding by electromagnetic wire
Two. Frame - part of the magnetic circuit (supporting) frame, steel plate welded or cast rigid.
Three, armature core - magnetic circuit, 0.5mm thick silicon steel sheet laminated (outer circular groove).
Four, armature winding - circuit. The electromagnetic wire is wound (closed circuit is divided into several branches by electric brush).
Five. Commutator - mutual insulation between the commutator sheets (mica or plastic).
Six, brush device
A, brush, graphite or metal graphite.
B, brush holder, brush rod and wire connection.
7. Commutation pole-improved commutation, consisting of iron core and winding (occasional winding placed on the main pole in series with armature winding)
Three. Excitation method
1. definition: the way to get DC power from the excitation winding of the main pole.
2. classification: taking DC generator as an example
They are divided into two types: self excitation and self excitation (including shunt, cascade and compound).
He excited: the magnetizing current is relatively stable.
The excitation current changes with the armature terminal voltage.
Series excitation: the excitation current varies with the load, because the excitation current is large, the number of turns of the excitation winding is small and the cross-sectional area of the conductor is large.
Compound excitation is mainly composed of shunt excited winding and series winding.
The small DC motor adopts permanent magnet type, * * explanation: in order to reduce the volume.
2. type and rating of DC motor (typeandratedvalues)
1. model: Z2-92
Core length code
Seat number
Second modification design
Direct
2. rating
Rated power: generator PN: output power; motor PN: output mechanical power;
Rated voltage: UN;
Rated current: IN;
(4) the relationship between ratings: Motor: PN=UNIN N.
The composition of DC motor
(1) stator: main magnetic pole, commutating pole, frame, end cover and brush device.
(2) rotor: armature core, armature winding, reversing device, fan and shaft.
(3) air gap
* notice: synchronous motor rotating magnetic pole; DC motor rotating armature.
1. the working principle of DC motor: a commutated motor with commutation device.
(1) Principle: the charged conductor in the magnetic field by the electromagnetic force and the formation of electromagnetic torque, propelling the rotor to rotate
(2) characteristic: f=BiL
A, the external voltage is not directly added to the coil, but through the brush and commutator to the coil.
So that the direction of the electromagnetic torque is unchanged, and the current in the armature conductor changes with the direction of its magnetic polarity.
C, armature electromotive force, back EMF (reverse from I), electromagnetic torque driving torque (same direction as n)
* * explanation: DC motors are reversible, and they are commutating motors with commutation devices.
2. Reduction of pulsation armature winding is made up of many coils in series.