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Essentials of Brushless DC Motor

All Dc motors used wound coils of wire in order to create magnetic field. In brushed motors such wires are not tied but are free to rotate to drive a shaft, they are basically called rotors.

The part which is fixed is called stators; where magnets are positioned in inner surface.

Its short form is BLDC Motor or BL Motor which is also known as electronically commutated Motor (ECM or EC). Electronic controller is used in order to switch the DC current to the windings of Motor which eventually rotate the rotor. The same controller helps to adjust the phase and amplitude of DC current in order to speed and torque of Motor. The entire controller system is somehow similar to brushes of mechanical commutator which were used in many typical electrical Motor in past.

History:

In order to understand its origin one has to go back and check the interventions done by Mr Ernst Werner in 1856. With time these inventions gone under many different developments.

The journey was begun when power dimmer was invented which has power to convert Alternative current into direct current.

In 2003; Makita was first company who used them as a power tool. In start they assemble them only for defense and aerospace industries; later on with passage of time in 2009 they released Brushless Dc Motor with three impact drivers.

 

The whole theory was presented by them in AIEE paper, "Dc Machine with solid state commutation.

 

Later in 1962, T.G Wilson and P.H Trickey published article which was Brushless motors which were operate on Direct current. The major concept was actually the absence of physical switch for transmission of energy.

Advantages: 

1) They have High power to weight ratio

2) Consists of high speed having instantaneous control on speed which is called RPM.

3) High efficiency and durability

4) It need low maintenance cost

5) Can be used in various items like computers peripherals like disk drives and printers.

6) The invention of DC motors allowed replacement of old rubber belts with direct drive designs.

7) Increase reliability

8) Reduce noise pollution

9) Eliminate sparks from commutator

Disadvantages:

The disadvantages arise here are because of the commutator installed in it. Here some of them will be discussed;

1) The friction in the brushes side along the commutator cause low power

2) The brushes used in motors are very soft which due to friction become damaged and need to be replaced because then they can't be used hard disk motors or in some other applications

3) In sliding brushes the electric resistance caused which eventually drop the voltage in main circuit of motor which is called brush drop which consume extra energy.

4) Due to the repetition of abrupt current switching, it causes sparks in commutator which cause fire hazards in explosive atmosphere.

Purpose: 

During manufacturing the brushless DC motors are basically used for motion control, acquisition and positioning of whole system.

Construction:

The construction is similar to permanent Magnet, but it has something new that it might use neodymium Magnet which will work in two ways. One they might be out runner’s means that stator in motor is surrounded by rotors, or secondly it might be in ruuner’s in which the rotors are surrounded by stators.

The third opinion option can also be available when the rotors and stators and flat and parallel with each other which is called axial.

Variations in construction:

Brushless motors can be constructed in various ways. Permanent Magnets are part of it. Three different stators are winded across the rotor, which the relationship in reverse way in between coil and magnets. Out runners mostly have more poles which are set up in triplet’s position in order to maintain the group of windings. In all Brushless DC motors, the coils used are stationary.

The delta connection is installed which connects all the three windings.

Usage in transport:

They are found in different hybrid, electric and main transport vehicles. They can also be used in electric bicycles which are located in wheel hub where the stators are fixed to axle. In exactly the same way they are installed in scoters.

They have expected life of 10,000 hours.

Difference between brushed and Brushless motors:

People often get confused in both of them because it has very minute difference in it. Brushed motors basically are driven through mechanical force while Brushless DC motors through electrically force.

In brushed motors, it contains stationary part in permanent Magnet. Stator is stationary part in it. When continuously the flipping of polarity happens it cause the spinning motion. This design is very simple but it contains some disadvantages like they are less efficient, hotter, contains shorter life span and requires more maintenance.

Whereas in Brushless DC motors, the whole phenomenon got exchanged. Here the rotors have permanent Magnet and stators create mechanical. Similarly they have also some disadvantages which are; they require more electronic controller, they are more expensive and complex to understand

 

Which one is better?

Both have significantly working better and giving proper results. The betterment of both depends on the cost of production. In both of them the brushes motors are less costly and are produced in mass level whether as the brushless motors are expensive. Despite of their low cost some other benefits of brushed motors are that they are simple to operate, reliable and are easily controlled.

 

Conclusion:

If someone is interested in wholesale purchase of any kind of DC or AC motors they can shop it easily at Mag spring. They accept all kinds of order weather it is for commercial use or personal use. Their catalogue is available at their website

As the cost of Brushless DC motors and their associated items are getting decreasing day by day, that’s why they are finding their way to excel in many different applications or in other fields.

There is one other benefit of using Brushless DC motors as compared to brushed one; feedback. Obviously one will always require feedback in order to know his performance. From rotation data, one can check his performance which exists in Brushless motors.

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