This is my first attempt at electrical engineering, so I'm sorry if this question seems basic, I couldn't seem to find answers anywhere.

I want to wire a 12v motor to an on/off switch and power with a wall plug. I intended this motor to be 18v so that is the power plug I bought, though come to find out after receiving it it is 12v, I firstly want to know if this is safe to power with the wall plug that I currently have.

Secondly, as it is currently connected (positive wire to switch and switch to motor, negative wire directly to motor) the motor runs smoothly when power is first supplied, but then goes on and off how can I prevent this so my motor runs smoothly?

Again, I am completely ignorant of this field and have tried my best to piece together my understanding of everything i'm working with, so please keep that in mind.

Thank you!

wall plug i'm using

Motor I'm using

  • \$\begingroup\$ Generally speaking, you should not exceed the recommended operating voltage of a device. \$\endgroup\$
    – Daniel
    Commented Apr 30, 2019 at 21:46

2 Answers 2


Judging from the motor picture, you have a fairly powerful motor RS-550 class, from some power tool/drill or other appliance. The motor start-up current (or load current) is likely above the capability of your power supply, and the supply goes into sporadic shutdown mode, and back. If your power supply is already giving out just 12 V instead of 18V, it already operates at the verge of shut-off, it could be thermal or overcurrent shutdown. This RS550 motor, for example, takes 1.4 A just for idle rotation at 12V. The motor will likely run at higher voltage, but the idle current will be proportionally higher.

Get more powerful supply, something like 12 V 5 A.

  • \$\begingroup\$ Thank you for the response,I want to use the motor in a sculptural project (art student)where it presses through leather lightly with a needle and ink to make lines actively (like a sewing machine but with ink)but now I'm now worried that this motor would be too harsh for that when powered properly.I want the motor to move fast enough to give pretty clean lines without tearing up the leather while people feed it through the machine.Do you have a recommendation for a type of motor to use that would move fairly fast but less overkill? would there be one that could operate with the power I have? \$\endgroup\$ Commented Apr 30, 2019 at 22:32
  • 1
    \$\begingroup\$ You will probably need a speed reduction gear. Any very small motor will likely run too fast. You can probably buy a motor with a reduction gear attached, It may be quit difficult to find a motor for which the 18-volt power supply will be suitable. \$\endgroup\$
    – user80875
    Commented Apr 30, 2019 at 23:18

This is my first attempt at electrical engineering... I am completely ignorant of this field and have tried my best to piece together my understanding of everything i'm working with

Engineering is very much about ratings and specifications. You seem to know that you have a 12-volt motor. Is that all you know about it? Where did you get that information? Very small DC motors are somewhat forgiving of excess voltage, but applying 50% excess voltage is rather reckless.

Do you know anything else about the motor? You can't do very much with virtually no information about the motor ratings and specifications. If you want to do something with a motor with no ratings and specifications, the best thing to do is to get a multimeter and start getting data. For testing, start with 1.5 volts, not 18 volts.

  • \$\begingroup\$ DC12V is written on the motor body. As well as .RS-550V, armature 3024B (or 8024B). \$\endgroup\$ Commented Apr 30, 2019 at 23:15

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