A DC motor is an electric machine that converts electrical energy into mechanical energy or mechanical rotation. In the DC motors working process, electrical currents are generated to create a magnetic field that powers the movement of a rotor in the motor.
The working Principle of DC Motors
The principle ofDC motors working is the Lorentz Law, which states that when a current-carrying conductor is placed in a magnetic field, it experiences a mechanical force. Fleming's left-hand rule gives the direction of the force while F = BIL gives magnitude. Where B = magnetic flux density, I = current, and L = length of the conductor in the magnetic field.
Applying this rule in DC motors working; if you stretch the left hand's first, second, and thumb fingers in a perpendicular direction to each other, the direction of magnetic field=first finger, direction of the current =second finger, then the thumb=direction of the force experienced by the current-carrying conductor.
Direct current supply creates an electric current that sets up the armature winding. In this case, current-carrying armature conductors experience a force resulting from the magnetic field.
What are DC Motor Parts, and how do they work?
For effective DC motors working, the motor should have the following parts;
Stator: This is a static unit containing the field windings and receives a power supply.
Rotor: This partof a DC motor creates the mechanical rotations of the motor.
Yoke:A Yoke is a magnetic frame that provides a protective cover to keep the motor's inner parts safe and supports the armature. The yoke also encloses a DC motor's magnetic poles and field windings.
Magnetic poles:The magnetic poles have two parts: The Pole Core and the Pole Shoe. The pole core holds the Pole Shoe over the yoke while the Pole Shoe carries slots for the field winding and spreads the produced flux by the field windings into the air gap between the rotor and stator.
Field Windings:The Field Windings circle around the slots carried by the Pole Shoes and form an electromagnet that can produce field flux.
Armature Windings:Armature Winding is connected to the rotor and alters the magnetic field in its rotor path. These windings result in magnetic loss, which is reduced by using low-hysteresis silicon steel lamination at the armature core, creating the cylindrical structure of the armature core.
DC Motor Commutator:The commutator is a split ring made up of Copper segments usually connected to the armature and designed to commute the current to the armature winding. The commutator turns the coils on and off to control the direction of the electromagnetic field and torque for a unidirectional DC motor working.
Brushes: Brushesare made of Carbon or Graphite structures. Brushes and commutators work as a bridge to connect the static electrical circuit to the rotor. Brushes relay the generated current to the commutator, and then the current moves into the armature winding.
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