Types of Electric Motor
Brushless DC electric motor (BLDC motors, BL motors) also known as electronically commutated motors (ECMs, EC motors), or synchronous DC motors, are synchronous motors powered by DC electricity via an inverter or switching power supply which produces an AC electric current to drive each phase of the motor via a closed loop controller.
In a wound rotor induction motor, the rotor is wound as a 3-phase winding with magnet wire, the ends of which are brought out to three slip rings mounted on the motor shaft. Spring loaded brushes connect to these slip rings and in turn are connected to the motor terminal box.
A compound wound DC motor or rather a DC compound motor falls under the category of self excited motors, and is made up of both series the field coils S 1 S 2 and shunt field coils F 1 F 2 connected to the armature winding as shown in the figure below.
Small DC motors are used in tools, toys, and appliances. The universal motor can operate on direct current but is a lightweight motor used for portable power tools and appliances. Larger DC motors are used in propulsion of electric vehicles, elevator and hoists, or in drives for steel rolling mills.
Small DC motors are used in tools, toys, and appliances. The universal motor can operate on direct current but is a lightweight motor used for portable power tools and appliances. Larger DC motors are used in propulsion of electric vehicles, elevator and hoists, or in drives for steel rolling mills.
Working of double squirrel cage motor At starting of the motor, frequency of induced emf is high because of large slip (slip = frequency of rotor emf / supply frequency). Hence the reactance of inner cage (2 πfL where, f = frequency of rotor emf) will be very high, increasing its total impedance.
DC electric motor with wound stator Construction details Figure 1: Elements of a DC electric motor with wound stator: (1) Stator (2) Stator coil (3) Commutator (4) Brushes (5) Axis of rotation (6) Rotor (7) Rotor coil Functionality In principle DC motors with wound stator work in the same way as those with permanent magnets described in the previous chapter.
In an electric motor, the moving part is the rotor, which turns the shaft to deliver the mechanical power. The rotor usually has conductors laid into it that carry currents, which interact with the magnetic field of the stator to generate the forces that turn the shaft.
As in PMDC motor the field is produced by permanent magnet, there is no need of drawing field coils in the equivalent circuit of permanent magnet DC motor. The supply voltage to the armature will have armature resistance drop and rest of the supply voltage is countered by back emf of the motor.
A synchronous electric motor is an AC motor in which, at steady state, the rotation of the shaft is synchronized with the frequency of the supply current; the rotation period is exactly equal to an integral number of AC cycles.
This article is devoted to slip ring induction motors. As discussed earlier, a slip ring induction motor is an asynchronous motor, as the rotor never runs in synchronous speed with the stator poles. Learn more about the construction and operation of a slip ring induction motor.
Now let us discuss in detail, the most common form of induction motor, the “Squirrel cage" induction motor. The reason for the name “Squirrel cage" is because of the type of rotor used in these motors. Almost 95% of the induction motors used is of squirrel cage type.
The switched reluctance motor (SRM) is a type of stepper motor, an electric motor that runs by reluctance torque. Unlike common DC motor types, power is delivered to windings in the stator (case) rather than the rotor. This greatly simplifies mechanical design as power does not have to be delivered to a moving part, but it complicates the electrical design as some sort of switching system ...
Synchronous motor: Stator poles rotate at the synchronous speed (Ns) when fed with a three phase supply. The rotor is fed with a DC supply. The rotor needs to be rotated at a speed near to the synchronous speed during starting.
The driving force of an electric motor is torque - not horsepower.. The torque is the twisting force that makes the motor running and the torque is active from 0% to 100% operating speed.