My beard trimmer has a very weak motor, so I want to upgrade it with this DC motor.

I want to run it with 5V.

What is an adequate power supply for this? Do I need a DC motor starter? What kind of starter do I need?

  • 1
    \$\begingroup\$ Brushed motors do not need starters. Only AC motors need starters and DC brushless motors need a lot more than a starter to get spinning and stay spinning. \$\endgroup\$
    – DKNguyen
    May 9, 2022 at 23:12
  • 1
    \$\begingroup\$ You need DC power supply which can provide start current. It may be 10-12 times of work current. \$\endgroup\$
    – user263983
    May 9, 2022 at 23:34
  • \$\begingroup\$ But it's impossible to find a power supply with 5V and 24A. What's the solution for this problem? \$\endgroup\$
    – Dark Night
    May 10, 2022 at 7:55
  • \$\begingroup\$ something as this could be helpful (to be tested, you did not specify voltage input?) input 12V output 5V-20A amazon.nl/… \$\endgroup\$
    – Antonio51
    May 10, 2022 at 8:12
  • \$\begingroup\$ You want a PSU that goes into current limit (CC mode) instead of shutting off. Then calculate the torque you'll get at that current. If that torque is enough to let the trimmer start, it'll come up to speed, just a bit more slowly than with its rated stall current. \$\endgroup\$
    – user16324
    May 10, 2022 at 10:54

1 Answer 1


At 6 V the initial startup ('stall') current is specified at 24 A. Therefore according to Ohm's law the resistance should be 6/24 = 0.25  ohms, and the startup current at 5 V would be 5/0.25 = 20 A.

Power supplies that can do 20 A at 5 V are available, but they are generally large and expensive. One cheap option might be an ATX-12V PSU from an old PC.

Next problem is that the motor will spin at over 12,000 rpm with much more torque than the original motor. Your trimmer may not be able to withstand this power for long.

  • 2
    \$\begingroup\$ "Your trimmer may not be able to withstand this power for long." Or your face. \$\endgroup\$
    – JRE
    May 10, 2022 at 8:25
  • \$\begingroup\$ Thank you sir!!! \$\endgroup\$
    – Dark Night
    May 10, 2022 at 10:04

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