DC motor and power questions?

Using Arduino Motors, Mechanics, Power and CNC
1

Hi everyone... im new in electronics and arduino in general.
If my questions seems basic and general understanding i apologize in advance.

recently i bought an arduino uno, H bridge L298N and 2 DC Motors.
My question is in relation to H-bridge and DC motors..

  1. The DC motors i purchased from my local shop doesnt have any volts or amps identified.
    the shop keeper told me they were 12v DC motors and he isnt sure about Amps.
    i went to the same shop few weeks later with the same motors and another staff told me they were 6V motors. i do not know who is right? i dont have the receipts to return the motors as well.
    is there any way i can find out the amps and volts of my DC motors?
    (ps i have seen youtube videos but the problem is if i supply 12 volts the stall load amp is more then double of 6V Amps.) so which one should i use?

  2. suppose if i have 2x DC motors with (12V each with 1amp)
    what will be my power input to the H-Bridge (Volts and amps)
    so that i can power the 2 DC motors and the arduino.

thanks for taking the time to read my post.
kind regards

2

If the motors have no markings then there's no easy way to tell their specification. If you post a picture including something like a ruler to give it scale there's a chance someone may know them but it's not really very likely.

I'd say the best approach is to start with 6V and if the motors run well enough for you then that's all you need. It never does any harm to run motors on lower voltage than the maximum that they are designed for.

But note that the L298N is not very efficient so you'll have to supply about 8 or 9V to get 6V at the motors. Something like a 9V 2A power supply or maybe 6 x AA batteries.

Steve

3

If you measure the winding resistance of the motors that will enable you to
determine the stall current for the motor - stall current = supply voltage / winding resistance.

If the power supply can supply that current, it'll handle that motor fine.

Check the motor driver can also handle that level of current.