**The Art of Conversion: Exploring Motor Types as Generators**

When it comes to integrating motion in projects, hobbyists often have three primary motor type options at their disposal: DC motors, BLDC motors, and stepper motors. Their primary function is to convert electrical power into mechanical power by applying a DC voltage or more complex voltage applications.

**Understanding Motor Functionality**

Wanting to learn more about the working behavior of such motors? It's highly recommended to watch videos covering the three motor types in question. One popular experiment that many have attempted involves soldering an LED to the input terminals of a DC motor, which miraculously illuminates the LED due to reversing energy flow.

**Generator Applications**

But why use generators? From an industrial perspective, most electrical energy is generated by a generator whose shaft is spun by turbines fueled by gas or coal. For hobbyists, a generator can be useful for windmill experiments, making it ideal for simulating constant torque on the generator shaft.

**Experiment Setup**

To simulate this scenario, an ODrive BLDC motor will be used in combination with a 3D printed motor mount and attached encoder to the motor shafts. The fitting o-drive control boards make this motor powerful and versatile. However, due to its industrial nature, a more appealing graphical interface like VESC will be utilized for this experiment.

**Measuring Efficiency**

To measure the efficiency of the system, input power and output power will be recorded during the experiment. The load used will consist of 50 Ohm power resistors added to other components connected to DC motors, which only produce a DC voltage. On the other hand, stepper motors require two full bridge rectifiers and capacitors to turn their sinusoidal voltages into a usable DC voltage.

**Conclusion**

This video is sponsored by JLCPCB, ideal for cheap and fast PCB turnarounds. The ODrive BLDC motor with an attached encoder and fitting o-drive control boards makes it powerful and versatile. However, due to its industrial nature, a more appealing graphical interface like VESC will be utilized for this experiment. The goal is to find out which of the three classical hobbyist motors is best suited as a generator.

WEBVTTKind: captionsLanguage: enWhen it comes to the integration of motion in projects,then hobbyists usually have three big motor type options they can choose fromThere's the DC motor, the BLDC motor, and the stepper motorTheir job is to convert electrical power into mechanical powerby sometimes simply applying a DC voltage andSometimes applying that voltage in a more complicated wayIf you want to learn more about the working behavior of such motorsThen I would highly recommend you to watch my videos about the mentioned three motor typesAnyway, what everyone probably tried out at some pointwas soldering an LED to the input terminals of a DC motor andspinning its shaft, which miraculouslyilluminated the LEDThe reason is that we reversed the energy flowmeaning we now create electrical energyfrom mechanical energy and thus, use the motor as a generator andThis brings me to the subject of this videowhich is about conducting a couple of experimentsin order to find out which one of those three classical hobbyist motors isbest suited as a generatorLet's get started...This video is sponsored by JLCPCB,which is ideal for cheap and fast PCB turnaroundsFrom prototypes to high-volume productionsthey can do a delivery on time in 99% of the casesSo upload your Gerber files to order high quality PCBsFirst off why would you want to use a generator?Well coming from the industrial side of view,most electrical energy that we consume isGenerated like the name implies by a generatorwhose shaft is spun by turbinefueled by for example gas or coalsBut coming from a hobbyist side,a generator can be useful for windmill experimentswhich you know is always fun. So,Let's imagine. We got a steady breeze andthus a constant torque on the generator shaftsto simulate the situation,I will be using an ODrive BLDC motorWith a 3d printed motor mountand an attached encoder to the motor shaftsIn combination with the fitting o drive control boards,this motor becomes powerful and quite versatile.Since it can be rotated very slowly,Almost completely silent and best of all,it can go to a position and stay there with a holding torque-Due to the utilization of the encoderSo, all in all, the ODrive is pretty awesomeBut, since a more appealing graphical interfacewould be more suitable for this experiment. I would rather switch to the VESCAbout which I also talked in a previous videoNow after calibrating the ODrive motorwith the VESC tool I will be using the duty cycle controlfor this experimentThat means that is a duty cycle and thus averagevoltage will be applied to the motor phaseswhich, on the other hand, means that as soonas a bigger load gets attached to the motorthe rotation speed would decreaseWhich would be just like attaching a bigger load to a constant wind forceDuring the experiment,I will be recording the input power of the motor andand the output power of the generatorand thus at the end calculate the efficiency of the whole systemAs a load for the three generators, I will be using 50 Ohm power resistorswhich are added to about any other componentsto the DC motorsince it only produces a DC voltageThe stepper motor, on the other hand,with its four wires just delivered two beautiful sinusoidal voltagesWhich require two full bridge rectifiersand capacitors in order to turn them into a DC voltage as wellLast but not least, we got the BLDC motorwhich is the most complicatedSince it offers 3 phase shifted,not that beautiful looking sinusoidal voltagesBut luckily the motor is configured in a star build-upwhich means we can use a "sechspuls Brückenschaltung"Basically a full bridge rectifier with two more diodesand capacitors, in order to once again, get a DC voltage on the outputand with the electronics being completedit was time for the final step:the mechanical connection between the motor and the generatorsNow for the DC motor and the stepper motor,it was simple since I had an 8 mm to 5 mm shaft coupler laying aroundBut of course, that would not fit for the BLDC motor shaftso I downloaded another shaft coupler from thingiverse3d printed it, enlarged its holes to 8 mm's andmounted it onto the BLDC motor andWith that being done. It was time for the experiment.I utilized the duty cycles 0.1, 0.15, 0.2 and 0.25and like stated before,recorded the input power of the motorand the output voltage of the generator across the resistorSince we know the exact value of it, we can later easily calculate the output powerBut nevertheless, what stood out to me while recording the valueswas that the DC motor as a generatorWas rather loud and vibrated a lot during operationThe stepper motor on the other handrotated the smoothest and the BLDC motorwas a mix of both the previous generatorsand with the values being recorded it was time for the evaluationNow, the output power of the BLDC was the lowestWhile the DC and stepper motorwere able to output about the same at four point something wattsThe average efficiency of the DC motor and the stepper motorwas around 20-30%Which is acceptable if you considerthat we included losses from the VESC,the motor, the mechanical connection, the generator, and the rectifierand also, we did not have a variable load on the outputsBut what was definitely not acceptablewas the efficiency of the BLDC motorwhich was at four percent at bestWhich brings us to the question: what is going on here?For that, let's look at the DC motorwhose model number tells us that it is a gear DC motorWith an RPM of 85 at 12 volts and a gear ratio of 1 to 86In Case you don't know, a gearbox like it's attached on top of the DC motorConsists of.. you guessed it...GearsTheir job is in this case to decrease the rotation speedof the motor, but increase its torqueThat means without the gears the DC motorwould have rotated with an RPM of around 7310and was easily rotatable by handBut with the gears the RPM decreased to 85and the shaft was no longer easily rotatableDue to the increased torqueWhat I'm trying to sayIs that the DC motor did only work so well as a generatorbecause the gear system increased its rotation speed significantlyNow, looking over to the poorly behaving BLDC motor,and we realized that the gear systemWould have increased its rotation speed and performancesignificantly as wellsince this one is rated for 270kVwe would need an RPM of 270to get an approximate 1 volt output voltageWhich basically means we need in higher rpm to get useful voltage?Which the wind force will definitely not deliver, but the gearbox could do thatThe stepper motor, on the other hand, did work so well due to its motor constructionwhich is primarily intended for lower rpm tasks (ex. 3D printing)Simplified speaking, fast rotating motors need gearbox when used as a hobbyist generatorwhich brings me to the conclusion of this experimentDC motors are the worst optionBecause due to the construction they mostly require:a high RPM, Not rotate well enough, and have lots of mechanical wear off due to the carbon brushesIf you want it simple and not worry about much,then go with the stepper motorsince it can be used even without a gearbox,rotates well, and outputs enough power for fun little projectsand if you want it professional, but complicated,then go for the BLDC motor with a suitable gearboxsince they are mechanically the bestand are able to output lots of power. If you go for the right ones andwith that being said,I hope you enjoyed my small experiments. If you agree or disagree with my opinion,Then feel free to share yours in the comment section belowAs always, don't forget to Like, share, and subscribeStay creative... and I will see you next time!