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I am trying to get some stable output from a Brushless power generator/motor/turbine which i purchased from Aliexpress

enter image description here

Mini Micro Small 3 Phase Turbine

To check if it works i tried to rotate it and LED blinks.

Added some toys gears in front of it and running it fast i am able to run over 7 3/5 mm leds so looks like it is generating around 10 Volts with a current of around 150+ milli amperes.

Now i want to get a stable voltage something like 5 Volt so i added a Voltage IC 7805 and then added couple of LEDS. I still didn't added a capacitor as was not sure how much value of capacitor i really needed.

So it is like this Turbine -> 7805 -> 5 mm Led - no other electronic component

In this case when i run the motor - the LEDs just blink for once (0.5 seconds) and then unless the motor fully stops then didn't blink at all. And if it run it again it again just blink for a second.

Is i am missing only the capacitor and what about what value? or something else is needed more to prevent damage to IC/Motor like some diodes etc?

I am also curious that my cheap Multimeter (under $10) does not show any voltage out of the IC and of motor but works for AAA/AA etc.

Any ideas are appreciated

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  • \$\begingroup\$ That aliexpress link requires me to log in \$\endgroup\$
    – Marcus Müller
    Commented Jan 8, 2020 at 9:30
  • \$\begingroup\$ So, I'll go by the name of the product alone: This is a three-phase generator, i.e. et produces AC. LEDs and the 7805 need DC. You don't have a rectifier. Hence, this doesn't work. Build a rectifier. \$\endgroup\$
    – Marcus Müller
    Commented Jan 8, 2020 at 9:32
  • \$\begingroup\$ Is this completely a toy, or do you have the slighest interest in practical use? \$\endgroup\$
    – Harper - Reinstate Monica
    Commented Jan 8, 2020 at 20:20
  • \$\begingroup\$ @MarcusMüller - should not asked for login - may be you can cross the popup or may be they are forcing you in a particular region, I added a snapshot as well. \$\endgroup\$
    – Moons
    Commented Jan 9, 2020 at 7:10
  • \$\begingroup\$ @Harper-ReinstateMonica sorry for a belated reply. I really want to create some practical application for home usage and was trying to learn the stuff. I am more into programming side/arduino but really want to know/understand about basic building blocks by doing something meaningful for personal use \$\endgroup\$
    – Moons
    Commented Jan 9, 2020 at 7:13

1 Answer 1

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A 3-phase machine produces AC:

I am also curious that my cheap Multimeter (under $10) does not show any voltage out of the IC and of motor but works for AAA/AA etc.

Your multimeter is set to DC when it can measure the voltage of batteries.

DC is not AC.

LEDs and the 7805 need DC. You don't have a rectifier. Hence, this doesn't work.

Build a rectifier.

If you build a 3-phase rectifier, you will leed relatively little capacitance to stabilized the output voltage. How much you'll really need depends on your requirements for voltage accuracy, and the current you draw and the current the generator can supply.

PS: You're operating the 7805 outside its specification by providing it an inverted supply voltage half of the time; that's why it shuts down. Chances are that doing that damages the IC.

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  • \$\begingroup\$ thanks for the answer, sorry i got messed up between AC/DC - when i got the motor it has 3 pins and on two pins led is added and it being lit continuously so got more confused. May be LED is blinking but not noticeable well to me. I will go ahead and build a rectifier, are normal cheap diodes will work for rectifier like 400X ones. thank you \$\endgroup\$
    – Moons
    Commented Jan 9, 2020 at 7:08

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