Electric Motor Manufacturers

How do Electric Motors work?

The basic idea behind how electric motors work is simple: the rotor spins inside a stator that is connected to an electrical supply. The rotor rotates when an electromagnetic field produces attractive and replusive forces. When the rotor turns faster than the magnetic field, it recharges the battery and acts as an alternator.

The rotor and electromagnets in an electric motor are connected by coils of wire. When power is applied to a coil, the coils of wire turn into an electromagnet. This electromagnet attracts the opposite pole of the magnet. The current is then switched from one pole to the other by changing the polarity of the commutator.

The physical principle of electric motors is the same for both DC and alternating current (AC) motors. The basic premise is that a magnetic field is created every time an electric charge moves. In a simple DC motor, a magnetic field is generated on the stator’s two components.

Differences and connections between DC motors and AC motors?

Taking the motor as an example, if the motor wants to work, it must rely on the electromagnetic force induced by the rotor winding to drive the rotor to rotate. Therefore, in order to ensure the stable and continuous rotation of the motor, the induced electromagnetic force in the rotor winding must keep the same direction. For DC For the motor, the direction of the stator magnetic field does not change, so if the current in the rotor is not commutated, the direction of the electromagnetic force received by the rotor during the rotation will change, and the continuous rotation of the rotor cannot be guaranteed. That is, as long as the direction of the electromagnetic force in the rotor windings is consistent, the rotor can continue to rotate.

The working principle of DC and AC motors is the law of electromagnetic induction, but there are also differences between the two, which can be understood through the different starting methods of the two. The rotation of the DC motor rotor (armature winding movement or force) is because the energized armature winding is subjected to electromagnetic force in the magnetic field, so the premise is that there is current in the armature, so the DC motor needs armature current to start; When the motor starts, as long as alternating current is applied to the stator, a rotating magnetic field will be generated.

Since this magnetic field is moving, the rotor winding will induce an electromotive force. As long as the rotor winding can form a closed loop, a current will be generated, and an electromagnetic field will be induced. The force drags the rotor to rotate, so the premise of the rotor movement of the AC motor is that the magnetic field is rotating, which is the difference between the two in the initial state of movement.

Why Some Motors Use Insulated Bearings?

Flashovers caused by induced currents on the spindle and bearings can lead to defects such as corrosion of the bearing surfaces, shrinkage cavities on the metal surfaces, and grooves in the bearing rolling tracks. One of the most important features of insulated bearings is that there is a very thin (um level) coating on the surface, which is responsible for electrical insulation and can resist electrical flashovers generated at voltages over 500V. Thicker coatings can resist 1000V. High voltage discharge.

First of all, for safety, at high frequency, the rotor induced current will be very large, preventing the motor shaft current. If the electrical insulating bearing is not used, the current will flow through the bearing to form a circulating current, and the bearing will be easily damaged by heat or electric water splash. The most significant feature of the electrical corrosion of the bearing by the high-frequency shaft current in the variable frequency speed regulating motor is the dense groove stripes produced on the inner and outer rings and balls of the motor bearing. Therefore, the motor must be electrically insulated at one end.