Be it computer printers, fax machines, elevators, water pumps, cars, printing presses, etc., electric motors play a vital role in almost every aspect of modern life. Being an electromechanical device, it converts electrical energy to mechanical energy. The motor operates by generating rotating magnetic fields to produce rotational force. Thus, the force further drives the shaft to run the appliance.
An electric motor comprises of two important elements:
- Stationary Stator (It generates magnetic fields of the desired shape)
- Rotating Rotor (It generates a magnetic field to interact with the fields generated by the stator).
Depending on the type of electrical power applied and different operational and safety features, electric motors are categorized into two:
- Direct current (DC)
DC electrical motor was prominent in the 1880s where it was used for both low and high power applications. It could drive heavier equipment which requires easier maintenance and operation controls.
- Alternating current (AC)
Though by 1890, AC motor was developed, it is now that industry professionals have started inculcating AC motor compared to that of DC as it provides higher levels of torque. Additionally, it drives complex and more fragile equipment.
Choosing The Required Electric Motor
Remember, if an incorrect motor is attached to the equipment, it can cause significant damage to the machine. Hence, according to the equipment installed, the right electric motor can be chosen. There is a wide range of electric motors from fractional single and three-phase motors to large medium and high-voltage motors such as:
- Single-phase motors: Single-phase motors have limited torque. They do not generate a rotating magnetic field but an alternate field. That means it needs a capacitor for the start-up.
- Compressor Duty Motors: Meet the high torque demand of air compressor loads by these high compressor duty motors. The rolled steel heavy-duty air compressor motors have special electrical and mechanical features that ensure long service life. It works at 230-volt single-phase and has a standard NEMA frame.
- Three-phase motors: Three-phase motors are suitable for applications that need lower RPMs and higher power efficiencies. Three-phase motors are directed by three alternating currents of the same frequency and can have speeds ranging between 900 and 3600 RPM. Three-phase is the most widely used type of electric motor in the industrial sector as it transfers more power. It produces power over 150% greater than that of a single-phase motor.
Three-phase motors used for general purposes are available as
- Drip-proof motors
- Totally Enclosed motors
- Explosion-Proof motors
Technology And Its Purpose
Let us look at the role of technology in the manufacturing process of electric motors:
1. COPPER ROTOR MOTORS- Avant-Garde For High-Efficiency Motors
So when we articulate the manufacturing process of electric motors and the key role of technology, copper plays a significant part in improving motor efficiency. In fact, the standard induction motor efficiency improves through more copper in windings, a higher-grade steel core, and improved cooling fan design.
The ultra-efficient copper rotor motors are alternating current induction motors ranging between 1 to 20 horsepower. Electrical appliances made of copper have become quite advanced these days. As per the proceeding research, it has been assumed that due to copper’s high conductivity it creates ultrahigh-efficiency electric motors. Though it has much lower electrical resistance than any other alternative material such as aluminum. Yet there is room for improvement.
Copper motors need to be created by hand assembling machined components which makes it laborious and expensive. But copper-based electrical motors can lead to a 20% reduction in electrical losses in the motor. Thus, it is applied to very large motor rotors.
As the copper rotor motor bars give lower resistance that means higher conductivity and reduced energy losses. Knowing the features of the motor design, copper rotors may have the following advantages:
- The total weight of the motor is less.
- Reduced heat generated which in turn requires less fan cooling, longer lifespan of the motor further saving energy and noise.
- Shorter stack permits fitting in compact spaces.
- Copper has great casting with a low risk of porosity.
- Lower corrosion in critical use.
2. PERMANENT MAGNET MOTORS
Permanent Magnet Synchronous Motor (PM) is established in industrial motor-driven systems. Powerful permanent magnets have replaced the aluminum bars in PM motor technology. It comprises rare earth elements which can be either surface mounted (SPM) or internally mounted (IPM).
According to motor manufacturers, permanent magnet designs have better efficiency as high as 3 NEMA bands compared to that of Premium Efficient AC induction motor. Permanent magnet motors are incorporated in compressor manufacturers because the motor can perform at very high speed.
For immediate start-ups and the applications where quick changes are required, direct current motors are used and permanent magnet DC motors can facilitate these simple startup operations.
But the drawback is, in the majority of cases the efficiency is not achieved without pairing the PM motor with variable speed drive (VSD). Secondly, though there is less copper in permanent magnet motor it still depends on copper for efficient operation.
It is used at wind turbines, air conditioning units, industrial motors, medical equipment, etc. Here are some advantages of PMM-
- High efficiency and reliability
- Low maintenance
- Required torque-speed curve
3. SWITCHED RELUCTANCE MOTORS
Switched reluctance motor (SRM) serves as a possible replacement and improved version in variable speed applications. It is a brushless DC electric motor that dispenses ceaseless torque. SRM electronic device when paired with the motor form an effective closely matched system. Though SRM has been around since the 1800s, due to the emergence of power electronics and computing capability it was commercially implemented.
Copper plays a key component in the design of a switched reluctance motor but the quantity and the type of copper wire are of utmost importance. Each turn of the copper coil wraps in order to fill the large stator slot allowed by the SRM design. When used in SRM, the strands of copper wire are twisted into the shape of a rope. It transposes the conductors reducing the skin effect.
SR motors work well for industrial applications as well as for other variable speed systems. It is used in automation, rock crusher, machine Tools, centrifugal machines: compressors and pumps, VSD systems, HVAC, etc.
Here are some advantages:
- Manageable and sturdy construction
- Constant power speed range capability
- High speed and torque
- High power density
- High efficiency
- Long endurance
- Consistent power-speed range capability
Each motor technology, whether PM, SRM, or CRM, each are unique, efficient, and reliable. All provide varied options to accomplish energy reduction objectives and improve performance. For better performance, you should know how to measure driveshaft length.
Are you able to select the best fit electric motor now? Well, connecting with a well-established electric motor store helps you shuffle the best option. Electric Motor was established in the year 1992 with an aim to provide motors as per the requisite and customer service, technical support even after the sale.