How to Determine DC Motor Current/Amp Draw (for beginners)

This video demonstrates the circuit, steps, etc., involved in determining the amount of current smaller brushed DC motors draw during no load, load, and stall conditions.
Datasheets and product descriptions often provide helpful starting points but one can't be sure about the amount of current individual DC motors will draw through the range of conditions (no load, stall, etc.) without actually testing them during each condition with a multimeter. This video talks one through the process.

[@FrankLopezx]

tho i gotta say this video was more helpful than 5 other videos i seen thus far

[@philomechtutorials]

Frank Lopez Appreciate the feedback and thanks for watching!

[@elobiretv]

if it draws over 20A, or whatver your meter is marked as, will it damage the meter?

[@FrankLopezx]

shouldnt that 12v motor be consider a LOAD since it has a gear box? while the 6v motor did not so no load unless the wheels are in the floor and mounted to hold the weight of the cars chassis/body?

[@philomechtutorials]

Frank Lopez Appreciate the comment and question. Both motors (6V and 12V) were of the gearhead type. Correct. Each motor is technically "loaded" in regards to the gears. But it's also fairly common to think of them as being in a "no load" state insofar as no pulleys, wheels, etc., are attached --- cases where gears are present but the shaft is "free wheeling". The load associated with the gears can matter if/when one is interested in performing more precise wear, efficiency, etc., calculations. But for the purpose of building simple robots, etc., (i.e., cases where a lot of precision isn't necessarily needed) it's often fine to assume a "load" doesn't appear until the "wheels touch ground". Hope these comments are helpful. Please let me know if there are more questions, etc. I will always do my best to help. Thanks for watching!

[@jorgewashington2981]

Excellent video! Thanks. You are a good instructor. One question from a noobie like me...why is the 12 v motor more efficient than the 6 v motor besides the build quality that you mention? Is it because the larger motor has more windings and / or larger magnets?

[@philomechtutorials]

+Jorge Washington Appreciate the feedback and question. Build quality (e.g., more precisely machined gear teeth in gear motors) and material selection are often the reason for one gear motor being more efficient, etc., than another. More windings, etc., can be very important but the overall purity and quality of the materials used as well as the care taken during the design and machining processes tend to make even more. Building a "functional" gear motor is not too difficult but building one that's especially efficient, plenty of torque, lower current consumption, etc., can quite the engineering and machining challenge. Hope these comments help. Thanks for watching!

[@jorgewashington2981]

Thanks for your response Philo and for sharing your knowledge with me.

[@robviolin1]

Very helpful, thanks.

[@robviolin1]

Thanks

[@MariLMatthew]

Amazingly helpful. Thank you!

[@AMalas]

My motor draws 1.2 Amps NO LOAD!!

[@philomechtutorials]

Anas Malas Thanks for the comment. That's definitely possible. It's not uncommon for some small scale hobby-type motors to draw an amp or more without a load.