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I recently bought a 24V brushless DC motor from ebay (link: https://www.ebay.com/itm/392320171299).

24V BLDC motor

I've been able to connect it to a 24V power source and it runs. I've been trying to control it via the connected PWM cable (white one, see link) but it doesn't work.

I'm using a raspberry pi and the https://docs.golemparts.com/rppal/0.12.0/rppal/pwm/ library to setup PWM. I've even measured the output pin and the voltage seems to change with my settings. However the motor still won't respond, it just runs at full speed.

Does the raspberry pi not provide the PWM voltage required (3.3V) required for this 24V motor?

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  • \$\begingroup\$ Did you connect the 0V of the motor to 0V of the raspi? \$\endgroup\$
    – Kartman
    Apr 26, 2021 at 4:59
  • \$\begingroup\$ What is the 0V? Is that the yellow wire (FG)? And by 0V do you mean ground on the Raspberry Pi? \$\endgroup\$
    – Fallen
    Apr 26, 2021 at 6:09
  • \$\begingroup\$ Black wire on the motor to GND as raspi. Pay attention to the length of the black wire on the motor - if you extend it, then voltage drop might be an issue. In which case it may cause the raspi to fail. A raspi isn’t intended to control things in the real world without protection. \$\endgroup\$
    – Kartman
    Apr 26, 2021 at 6:16
  • \$\begingroup\$ Is that OK to do with a 24V motor? Also the motor's red wire connects to a 24V power supply. I have extended the PWM wire, but only about 6 inches. \$\endgroup\$
    – Fallen
    Apr 26, 2021 at 6:39
  • \$\begingroup\$ Current flows in a loop so the raspi gnd needs to be connected to the motor gnd/0V. I don’t know why raspi calls its 0V GND - so very confusing as not all GNDs are grounded. Nevertheless be aware that voltage drops can cause problems. \$\endgroup\$
    – Kartman
    Apr 26, 2021 at 6:46

1 Answer 1

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Black wire on the motor to GND on raspi. Pay attention to the length of the black wire on the motor - if you extend it, then voltage drop might be an issue. In which case it may cause the raspi to fail. A raspi isn’t intended to control things in the real world without protection.

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