What is an electric motor? It can convert electrical energy into mechanical energy. It provides a wide range of applications and has a vital role in every industry. The electric motor is considered the workhorse of the power transmission industry. We can found it in power tools, machines, cars, ventilation systems, pumps, household appliances, and many more. There are many types of electric motors available in the market for different purposes and applications. We choose the right electric motor based on the operation and voltage requirement.
The basic working principle of the electric motor is Faraday’s Law of Induction, that is a force is generated through the interaction of the motor’s magnetic field and electric current in the wire winding. There are two critical parts which are the field winding and armature winding in the motor. The field winding is to generate a fixed magnetic field, while the armature winding acts like a conductor that is arranged within the magnetic field. Due to the magnetic field, the armature winding uses the energy to produce a force in the form of torque that makes the motor’s shaft runs.
Every motor has its own characteristics, we classify them based on the features and standards. The electric motor can be divided into three main categories which are DC motor, AC motor, and special purpose motor. It can also further break down by specific purpose electric motors such as stepper motors, linear motors, gearmotor, or servomotors.
AC Motor
AC Motor uses alternating current such as electric generators, inverters, or power grids as an input to convert into mechanical power. It is efficient, quiet, durable, and flexible. There are three types of AC motor, including synchronous motor, induction motor, and linear motor. AC motors are available in single and three-phase configurations.
1. Induction motor, also known as the Asynchronous motor, is the simplest and most rugged electric motor commonly used in the world. The rotor is required to rotate at a slower speed than the magnetic field to create the existence of an induced voltage. The voltage is induced in the rotor without the need for brushes. According to the rotor construction, it can be classified into two types which are squirrel cage and phase wound. The squirrel cage induction motor includes a squirrel cage-type rotor and it lowers the magnetic locking of the rotor and humming sound. On the other hand, the type of motor using the slip ring rotor is known as phase wound rotor.
2. Synchronous motor can be used for a wide range of applications. It rotates at the same rate as the frequency of supply current. It has the stator of an induction motor and the rotor of the DC motor. Asynchronous motor is designed to keep a constant speed, with the rotor synchronous to the rotating field. So there is no air gap between the rotor and the speed of the stator current. The synchronous motor can be classified into two types which are Reluctance Motor and Hysteresis Motor.
3. Linear Motor has unrolled rotor and stator, it generates the linear force instead of a rotational force and is commonly used for sliding doors and actuators.
DC Motor
DC motor converts direct current into mechanical power to produce rotational motion. The energy can be come from batteries, rectifiers, or other power sources that provide a constant voltage. It can produce more torque, better speed variation, and control over the AC motors. DC motors are available in brushed and brushless designs. Brushed is the oldest type of motor found in many toys and consumer appliances. It uses contact brushes to connect with a commutator to alter the current direction. It is easy to control and has excellent torque at low speed. However, it has a limitation on the speed and requires maintenance to replace the worn brushes caused by the heat. In contrast, brushless DC motors use permanent magnets for their rotor assembly. It provides higher efficiency, higher power density, less noise, and less maintenance required than brushed DC motors. Brushless DC motor is popular in the hobby market such as a ground vehicle or aircraft applications.
There are two types of DC motor which are the Self-excited motor and separately excited motor.
Besides the basic types of motor mentioned above, there are other types of special motors that have been developed for specific requirements of the industry, such as hysteresis motors, linear induction motors, servo motors, and stepper motors. For instance, the hysteresis motor is small and compact, the noise level of this motor is quite low and very suitable for those complicated applications that require soundproof features such as an audio recorder or sound player.
How To Choose The Right Motor
We need to consider few factors when selecting a motor for our applications. The requirements on current, voltage, torque, and velocity will decide which type of motor is the most appropriate. Current is the one that powers the motor and too much current can damage the motor. Voltage is used to maintain the net current flowing in a single direction and overcome the back current. A higher voltage results in higher torque. The voltage rating of a DC motor refers to the most efficient voltage level while operating. It is important to apply the recommended voltage as too few or too many volts can cause the motor to fail.
Operating torque indicated the amount of torque that a motor is designed to provide. Stall torque refers to the amount of torque produced when the power is applied at stall speed. We should always look at the required operating torque when selecting the right motor. Velocity also refers to speed (RPM). As we know that, motor runs at the highest speed is the most efficient. But it may not be true that if gearing is required, the addition of gearing will reduce the efficiency rate of the motor, which we also need to take into account of the speed and torque reduction.
In today, there are many different types of motor available. Choosing the right motor can support the use of the equipment and bring a high level of efficiency to the overall act of the system. MecHero Malaysia offers different types of electric motors for meeting your project requirements. You can always contact us at +6011-7000 7687 or email us at my.mechero@gmail.com for an inquiry about the supply of electric motors in Malaysia for industrial usage. As a steel and online hardware store Malaysia, we also supply a wide range of steel materials, general hardware, or mechanical components. Tell us your requirements now and we can advise you accordingly.
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