How to Determine DC Motor Current/Amp Draw (for beginners)
Why Electrical Engineering Stack Exchange recommends it
Electronics Stack Exchange users link it as a practical, hands-on demonstration of how to measure a small DC motor's running and stall current with a multimeter.
Recommended by 1 people across 1 different months, 2017 to 2022.
What it is
A 15-minute beginner tutorial from the philo mech channel showing how to measure the current a small brushed DC motor draws under no-load, loaded and stall conditions. It walks through wiring a multimeter in series with the motor and taking readings in each state.
What people said
Recommends hotmeatballsoup · 2022-12 · Electrical Engineering Stack Exchange · on “Why do DC motors draw more (and not less) current when they are stalled?”
I watched this video [this video] which shows a method of empirically estimating the amperage draw of a DC motor if you only know its voltage. The author of that video shows a multimeter rigged up to read the amps on the motor as its operating under 2 different modes: no load and stalled. What the video demonstrates is that the DC motor draws less amps when operating under no load than it draws when it is stalled completely. Although it makes sense when you think about, (the motor is straining harder so it likely is drawing more current), I'm not understanding how it relates to the V = IR formula. If the battery voltage (6V) is staying the same, and he's increasing the resistance on the motor so
Cites smntnz · 2017-10 · Electrical Engineering Stack Exchange · on “very low stall current in geared 12V DC motor”
I bought a small brushed (my guess) DC motor with integrated reduction gears off Banggood: here's the link to the product page: [LINK] Since it comes with no sort of technical data, aside from the rated rotational speed and voltage (3rpm at 12V with no load), I wanted to investigate more on it, so I measured the running current draw with no load, and the stall current by mechanically blocking the shaft and using a multimeter in "Amp mode". I'm a complete noob so I just followed this guy's tutorial: [this video] Although I haven't really measured the rpm to check if they match the rated value (speed is not a concern), the motor works just fine, but what I got was: a no-load current so low it could
Cites tlfong01 · 2021-05 · Electrical Engineering Stack Exchange · on “Motor Driver keeps dying/frying driving a worm gear motor”
Question The OP has so far fried four motor drivers. He wishes to know what went wrong, and how to avoid frying more motor drivers. Answer Part A - Analysis of the the OP's motor and motor drivers We will first study his motor and motor drivers, and then guess what went wrong. Uxcell JFC63R Gear Motor (Appendix A) My first impression is that it is a very powerful motor. I usually first look at the motor shaft. The shaft is 10mm diameter, which is for very powerful motors. The power is 80W, an of course is very powerful. This implies big current is need to drive this motor, and that the back EMF, which is proportional to the square of the motor current, is huge, and needs a powerful and fast