Motor electromagnetic

Motorul electromagnetic de curent continuu este compus din poli statori, rotor (armatură), comutator (cunoscut în mod obișnuit ca comutator), perii, carcasă, rulmenți etc.
Polii statorului (polii principali) ai motorului electromagnetic de curent continuu sunt alcătuiți din miez de fier și înfășurare de excitație. Conform diferitelor metode de excitare (numite excitație în vechiul standard), acesta poate fi împărțit în motoare DC excitate în serie, motoare DC excitate în șunt, motoare DC excitate separat și motoare DC excitate compuse. Datorită diferitelor metode de excitare, legile fluxului polului statorului (generat de bobina de excitare a polului statorului după alimentarea cu energie) sunt, de asemenea, diferite.
The excitation winding and rotor winding of the series-excited DC motor are connected in series through brushes and commutators. The excitation current is proportional to the armature current. The stator flux increases with the increase of the excitation current. The torque is approximately proportional to the square of the armature current. The speed decreases rapidly with the increase of torque or current. Cuplul său de pornire poate atinge mai mult de 5 ori cuplul nominal, iar cuplul său de suprasarcină pe termen scurt poate atinge mai mult de 4 ori cuplul nominal. The speed change rate is large, and the no-load speed is very high (it is generally not allowed to run under no-load). Reglarea vitezei poate fi realizată prin conectarea unui rezistor extern în serie (sau în paralel) cu înfășurarea excitată în serie sau prin comutarea înfășurării excitate în serie în paralel.
The excitation winding of the shunt-excited DC motor is connected in parallel with the rotor winding, and its excitation current is relatively constant. The starting torque is proportional to the armature current, and the starting current is about 2.5 times the rated current. The speed decreases slightly with the increase of current and torque, and the short-term overload torque is 1.5 times the rated torque. The speed change rate is small, 5%~15%. The speed can be adjusted by weakening the constant power of the magnetic field.
The excitation winding of the separately excited DC motor is connected to an independent excitation power supply, and its excitation current is also relatively constant, and the starting torque is proportional to the armature current. The speed change is also 5%~15%. The speed can be increased by weakening the magnetic field constant power or reduced by reducing the voltage of the rotor winding.
In addition to the shunt winding, the stator pole of the compound-excited DC motor is also equipped with a series-excited winding (with fewer turns) in series with the rotor winding. The direction of the magnetic flux generated by the series winding is the same as that of the main winding. The starting torque is about 4 times the rated torque, and the short-term overload torque is about 3.5 times the rated torque. The speed change rate is 25%~30% (related to the series winding). The speed can be adjusted by weakening the magnetic field strength.
The commutator segments of the commutator are made of alloy materials such as silver-copper and cadmium-copper, and are molded with high-strength plastic. The brushes are in sliding contact with the commutator to provide armature current to the rotor winding. The brushes of electromagnetic DC motors generally use metal graphite brushes or electroplated graphite brushes. The rotor core is made of laminated silicon steel sheets, generally with 12 slots, and 12 sets of armature windings embedded in it. The windings are connected in series and then connected to the 12 commutator segments respectively.