Brushless and brushless motors: what is the difference and which is better

Collector motors

Electric motors used in children's toys are small in size and low in power. Structurally collector motor consists of two permanent magnets mounted on the stator, and a rotor (armature) with windings. Note that there can be field windings on the stator, instead of permanent magnets.

A constant voltage is applied to the windings through the collector lamellas. Graphite brushes are used to supply voltage. In low-power motors, copper plates are used as brushes.

Collector motors are powered by both DC and AC. They have two wires for connecting the power supply.

Brushless motors

The name of the electric motor indicates the absence of a current collector. Which is the main design difference. This reduces friction losses and increases power. In this case, permanent magnets are mounted on the rotor, and the windings are placed on the stator.

Produced brushless motors, in which the magnets are mounted on the case. In this case, the housing acts as a rotor.

A special device (controller or commutator) is required to start the engine, which increases the cost of brushless motors.

Pros and cons of compared engines

Collector motors are used in children's toys, car models, ship modeling, etc. More powerful devices with a field winding are used in the automotive industry, household appliances, in a lathe or drilling and etc.

Widespread use is due to:

• Low cost.
• Ease of management. To adjust the speed, it is enough to have a rheostat, and to reverse - change the polarity in the excitation circuit or armature.
• Can be connected directly to the mains supply.
• The rotor speeds can be varied over a wide range.
• Small starting currents.

But with the simplicity of the device, collector motors have disadvantages:

• Low efficiency.
• Limited service life.
• The need for constant maintenance.
• Low reliability of the device.

However, such engines are not used in all industries. They cannot be used in explosive areas. When used at high speeds, the collector and brushes quickly fail.

The result is a decrease in power, and the current-carrying brushes begin to spark. Such a constructive difference leads to a rapid failure of the collector lamellas, interference in radio equipment.

The brushes have to be changed and the manifold re-machined, which shortens the life of the engine. This is the main disadvantage of such devices.

There is no collector in brushless motors. This is the difference between brushless motors and collector motors, and therefore there are no disadvantages mentioned above.

The advantages of such electrical machines are:

• The absence of rubbing parts reduces friction power losses. It is not required to constantly monitor the condition of the brushes, since they are absent. This difference makes it possible to increase the overhaul period.
• The possibility of using the body as a working body. This design difference allows the mechanisms to be used directly as wheels.
• Brushless electric motors, unlike collector motors, are more durable. Moreover, they are less susceptible to overheating, because there is no collector and brushes, which become very hot during operation.
• Instantly gaining momentum.
• They can be used in all branches of industry, in fire and explosion hazardous premises. Due to the lack of a collector, sparking does not occur, which is why they are better.

But this type of motor has a significant drawback: brushless models can only be used with a commutator driver. With the help of this device, the operating modes, speed and direction of rotation are set. At the same time, the cost of brushless motors is much higher. The difference in cost can be significant. This is how they differ from collector devices.

Light weight and high power - this is what is best combined in devices with remote control, for example, for a quadcopter, where the range and flight time depend on the weight and efficiency.

Conclusion

So, let's summarize and outline what is the difference between a brushed and a brushless motor, listing their features.

Collector motor:

1. There are brushes and a manifold that spark and wear out.
2. It is necessary to service more often, respectively, and the service life is not too long.
3. It is easy to adjust the speed just by changing the voltage.
4. To reverse, you just need to change the polarity.
5. The two previous facts allow them to be used in budget devices without complex wiring diagrams.

Brushless motor:

1. To start, you need a controller, which, although not too expensive, increases the final cost, circuitry and weight of the product.
2. They weigh less than collector ones, with the same power (but this is partially offset by the previous fact).
3. No brushes and no collector, therefore maintenance-free and spark-free.
4. Longer service life, it is limited only by the service life of the rotor bearings.
5. They usually cost more than collector ones.
6. Often they give out more torque on the shaft and revolutions.
7. In the presence of shaft position sensors, they provide greater stability of revolutions when the load changes (rigid mechanical characteristic). This is especially important when used on machine tools and hand tools.

From the author:

I will add that it is impossible to say unequivocally which is better or which is more powerful, you can find a collector motor the size of a refrigerator, or you can find a brushless motor the size of a fingernail. At the same time, both will perfectly perform the functions for which they are designed and used in specific devices, taking into account the requirements for their reliability and operating features. Each type of electric drive is good in its own way and ideal in design as such.

Now you know what is the difference between a brushed and a brushless motor, as well as what are the pros and cons of each version. We hope the information provided was useful and interesting for you!

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