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Not exactly sure what kind of AC or DC motor would be needed to make this. Is it even a realistic idea to make electricity by using a motor as a generator?

https://www.youtube.com/watch?v=V3NtSp6aAbs

Marcus Müller
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hello_world07
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  • The YT demo uses a small DC motor. – tlfong01 Jun 10 '22 at 02:34
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    I tried to use a small Dc motor as well but it didnt work. Do I have to choose one with a lower rpm? – hello_world07 Jun 10 '22 at 02:46
  • (1) Brush DC motor should do. (2) Perhaps use one motor to turn another (which becomes a generator), using this coupler, ... / to continue, ... – tlfong01 Jun 10 '22 at 04:09
  • (3) Rigid Shaft Coupler Motor Connector Copper Sleeve 3.17/4mm/5mm/6mm/8mm/10mm/12mm Ship Model Accessories - AliExress US $2 https://fr.aliexpress.com/item/2255800011543979.html?spm=a2g0o.search0304.0.0.262a17d6NdLdDY&algo_pvid=82b36294-edde-4ee1-86cc-85b4fdefe64b&algo_exp_id=82b36294-edde-4ee1-86cc-85b4fdefe64b-32&pdp_ext_f=%7B%22sku_id%22%3A%2210000000751466614%22%7D&pdp_npi=2%40dis%21USD%21%211.72%21%21%21%21%21%402101e9d116548336628984298e4a76%2110000000751466614%21sea&gatewayAdapt=glo2fra – tlfong01 Jun 10 '22 at 04:09
  • The Creative Crafts Guy https://www.youtube.com/watch?v=V3NtSp6aAbs seems using *DC motor GB370* @2:53 References: (1) https://raspberrypi.stackexchange.com/questions/137762/python-code-not-working-programming-a-motor-to-turn-on-using-a-switch-raspberr (2) https://raspberrypi.stackexchange.com/questions/94031/power-mosfet-driving-big-motor-problem (3) https://www.circuitlab.com/circuit/n7764g3wm5d2/irl540n_motor_2022jun0401/ (4) https://imgur.com/a/dxif3bJ – tlfong01 Jun 10 '22 at 04:19
  • I searched my junk box and found a JB370 motor which I think has a gear ratio of about 100 and 70rpm. So I think the no gear speed is around 7,000 rpm. Reference: (5)

    How to use motor drivers with H-bridge and PWM input, to control direction and speed of DC motors? Asked 1 year ago, Viewed 2k times https://electronics.stackexchange.com/questions/510755/how-to-use-motor-drivers-with-h-bridge-and-pwm-input-to-control-direction-and-s

    Appendix B - PWM Controlling Speed of JB37 Geared Motor

    Geared speed ~= 70 Gear ratio = 100 No gear speed ~= 70 x 100 = *7,000 rpm*

     – tlfong01 Jun 10 '22 at 06:32
  • So I have set up two JB370 DC Motors. (1) The first motor is driver by DC 12V. (2) The shaft of this first motor is coupled to the shaft of the second motor. (3) The first motor and second motor move at 70rpm. (4) The second motor after 100:1 gear ratio will move the internal motor shaft at 7,000 rpm. (5) Now I need to use a DVM to measure the AC voltage output which I expect to be 12V AC rms. (6) The setup pic: https://imgur.com/gallery/Q58VFm2. – tlfong01 Jun 10 '22 at 08:05
  • "Do I have to choose one with a lower rpm?" - yes. Or a motor designed to run on a higher voltage, eg. 12V, 24V or 36V (the higher the better). Inkjet printers and hair dryers often use a DC motor in this voltage range. Here's one that only needs 460rpm to generate 3V https://www.ebay.com/itm/264924712999 – Bruce Abbott Jun 10 '22 at 08:30

2 Answers2

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Almost any permanent magnet, brush-type DC motor (one having a commutator) should work as a generator. Don't use a brushless motor, as found in computer fans. Motors from an inexpensive battery-powered toy would likely work.

That said, the power output depends on the speed of rotation, the number of poles, permanent magnet strength, etc. Almost any small motor, when spun by hand, could light an LED, for example, but not a small incandescent flashlight (torch, for the UK) lamp.

DrMoishe Pippik
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It's a brushed permanent magnet DC motor,

It will need to spin quite fast to make enough voltage to light an LED. much more than the approximately 1000RPM seen in the video

Jasen Слава Україні
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