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Can DC Motors be Used as Generators?

Wind Power Generator

Many of the machines we have today run on electricity. Using electricity is very convenient because you can get it from different sources. For example, water and wind produce electricity. It is amazing how a simple DC motor can generate electricity. Can a DC motor be used as a generator? 

Yes! If you want to use DC motor as a generator, reverse how it runs, and you have a generator. A generator is like a DC motor that is running in reverse. A DC motor converts electrical energy to mechanical energy. Meanwhile, a generator turns mechanical energy into electrical energy. 

You can search various articles about this topic but look no further. I have written this article to show you how to use DC motors as generators. 

Can DC Motors Generate Electricity?

 

Again, the answer is yes. A DC motor can generate a fair amount of electricity by manually rotating the armature (rotor). The faster you spin the rotor, the more electricity it will produce. 

You can also attach an independent energy source, such as an engine or wind turbine, so it starts producing power.

Motor Rotor

Is DC Motor the Same as Generator?

 

DC motor is the same as DC generator when you view it from a mechanical standpoint. 

DC motor uses direct current (DC) electricity to create continuous rotation. DC generator creates a continuous supply of DC electricity when it rotates. 

Both the DC motor and generator use a commutator. It looks like a metal ring with splits. It simultaneously reverses the current and the electrical contacts from the generator coil. 

Difference Between a DC Motor and a Generator

RF-300CA Prorich Motor

From a technical perspective, a DC motor and generator have significant differences. The most glaring difference is in their conversion mechanism. DC motors transform electrical energy into mechanical energy, while DC generators change mechanical energy to electricity. 

Also, a DC motor uses electricity, but the generator creates electricity. 

Here are other differences:

Electromotive Force (EMF)

 

In a DC motor, a coil uses the EMF to the circuit. It also helps its axle rotate. A generator provides EMF to the connected load to create electricity.

Current

 

In a DC motor, the armature windings receive current. In a generator, the armature windings produce current.

Working Principle

DC motors use Fleming’s left-hand rule while generator uses Fleming’s right-hand principle. 

Fleming’s Left Hand Rule

Operation

 

The armature and field of a DC motor produce a magnetic field between them. The magnetic field powers up the shaft of the motor. 

In a generator, the shaft connects to a rotor. A mechanical force powers it up. 

How to Use a DC Motor as a Generator?

 

775 Motor Prorich

You can use any DC motor as long as it has a permanent magnet. That means it does not matter whether you will use a brushed or brushless DC motor. However, a brushed DC motor does not need any conversion. All you need to do is spin the shaft. Then, it will produce a direct current. 

A brushless DC motor will take extra work to transform into a generator. This type of motor uses an integrated circuit (IC) and a few transistors. These components convert the direct current (DC) into a three-phase alternating current (AC). 

Brushless Motor Pcb

Remove these components and replace them with diodes. The diodes will reverse the process by converting AC into DC. 

How to Increase the Output Voltage of a DC Generator?

 

There are two methods to increase the output voltage of a DC generator:

  • Rotate the coils faster
  • Use stronger magnets to boost the field current

However, doing this shortens the life of the generator. It also becomes more prone to fail. When you increase the speed or current, it works harder than it was designed to do. 

Which Motor Type Would Work Best as a Generator?

 

That depends on the motor application and what you want to achieve. If you want to get more power, you need a sizable motor to contain all the electricity that will be generated. If you are unsure how much power to expect, any motor type is okay. 

DC Motor for Small Application

 

If you are only using it as a hobby or conducting some small power experiments, you can use three types of motors:

  • Brushed DC motor
  • Brushless DC motor (BLDC)
  • Stepper motors

Dc Motor Used As Generator

Each of them has its advantages and disadvantages. Their use also depends on the type of experiment or task you are doing. 

A DC motor produces more noise and vibration while the stepper motor rotates smoother than the other two. The BLDC motor, on the other hand, is a combination of both the DC and stepper motors. It also has the lowest efficiency rate. 

When it comes to performance, the DC motor is the worst option because you need to increase its rotation speed to work well as a generator. They need a high rotation per minute (rpm) and do not rotate well. They also sustain a lot of mechanical wear because of the carbon brushes. 

The stepper motor is the best option because it performs best. Thanks to its motor construction. It can operate efficiently even without a gearbox. It also rotates well and generates enough voltage. It works well for lower rpm tasks like 3D printing and other fun little projects. 

How about the BLDC motor?

The BLDC motor works well for professional and complicated projects. It is the most efficient and can produce lots of power. However, you need one with a suitable gearbox. 

Just a word of advice: fast-rotating motors need a gearbox if you intend to use them as a hobbyist generator.

DC Motor for Medium-Sized Application

 

A DC motor with permanent magnets works well in medium-sized applications, like a wind turbine. They will still produce energy even if their rotating speed decreases. 

Some people might say that the voltage output is lower when the speed is lower. The point is you will still get electricity even if the motor is rotating slowly. 

What about a single-phase motor? 

The problem with using this type is it will stop producing energy when the motor slows down. So that might be a problem for you if there’s no wind. 

Conclusion

 

To sum it all up, a DC motor and a generator are similar and different. They are the same if you look at them from a mechanical perspective, but dissimilar from a technical viewpoint. 

A DC motor with permanent magnets works best in medium-sized applications like wind turbines. It generates electricity whether the motor rotates faster or slower. 

In small-sized applications like hobby projects, a DC motor is a terrible choice because it needs more rpm to become more efficient.

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