https://diy.stackexchange.com/questions/201721/how-to-debug-new-brushless-dc-motor-not-working

How to debug new Brushless DC motor not working?

Ask QuestionAsked 18 days agoActive todayViewed 2 times1This question was migrated from Electrical Engineering Stack Exchange because it can be answered on Home Improvement Stack Exchange. Migrated 4 mins ago.

I’m building an autonomous boat, for which I so far used this brushless motor powered by this drone ESC (both pictured above).

I now want to start using a more efficient motor, so I bought the 12V 4000RPM version of this motor (pictured below this message). I removed the old motor and connected up the new one. It gives the same beeping sounds when I calibrate it with the software, but after that, it doesn’t move at all. I use the exact same code and ESC setup with the new and the old motor. I tried the Go code I used for the other motor, and also tried some other example Python code with which the other motor also works great.

The wiring info of the new motor has 6 wires, as compared to the only 3 of the old motor. The wiring diagram of the new motor looks like this:

I connected it as follows:

• the + of the ESC => red wire of the motor
• the – of the ESC => black and the blue wire of the motor
• the PWM signal of the ESC => yellow wire of the motor

I’m not sure if this is the correct way, but it’s the best I could come up with. I’m not sure whther the -/minus of the ESC should also be connected to the blue wire, so I tried it both connected and disconnected. But none of my attempts make the motor spin.

And from here I’m kinda lost. Seeing that I’m more of a software guy than an electronics guy I don’t really know how to debug such a hardware problem.

Could anybody give me some pointers on what the problem might be, and more importantly, how you go about debugging something like this? All tips are welcome!

untaggedshareimprove this question  follow asked Aug 4 at 14:36kramer65

• 1The instructions show a 10K pot on green,yellow,blue. I would suggest trying that : the pot should provide speed control. (with Red and Black to the PSU, and leave grey open or grounded to change direction). – Brian Drummond Aug 4 at 16:01

add a comment

2 Answers

ActiveOldestVotes0

Your new motor is advertised as having a Built-in Drive hence it is not suitable for use with your ESC.

It’s possible you could rip out the internal driver and substitute yours, or learn to operate the internal driver (it probably comes from an industrial control tradition, not the 1-2 millisecond pulse of the RC hobby world), but questions on the usage of products (especially products with little documentation) are not on topic here.shareimprove this answer  follow answered Aug 4 at 14:43Chris Stratton10133 bronze badges

• Do you mean to say that the motor has a built-in ESC? So theoretically I would need to add a PWM signal directly to yellow line of the motor? – kramer65 Aug 4 at 14:56
• Both the circuit in the motor and your ESC are brushless motor drivers. It is rather unlikely however that the driver in industrial motor system you bought wants the same signal that your RC hobby ESC does, as it comes from an entirely different tradition of application. You’ll have to figure out what it does want and devise a way to create that… if in fact the new motor system is suitable at all. – Chris Stratton Aug 4 at 15:04
• Ok great. I’m learning a lot here. And with “figure out what it wants” I guess you mean to say what kind of PWM signals it needs? I will of course ask the seller for generic documentation, but do you have any specific questions which I might ask them? – kramer65 Aug 4 at 15:20
• What you need is a data sheet, not a connection diagram. A drawing of a waveform would help. But really, it is beyond obvious from the page that supplier is not a good place to be shopping unless you have enough domain knowledge to recognize exactly what they are offering and that it fits your need. You probably want to stick to RC hobby suppliers with familiar offerings. – Chris Stratton Aug 4 at 15:22
• 1Ok, I got a reply from the seller. They say they bought these motors from a company who went bankrupt so they have no information on it.. 😮 So yeah. No info whatsoever. I know this is not really the place for this, but would you have any tips on how to proceed with this thing? Do I disassemble it? Do I start throwing random PWM values at it? What would you do in this case? Do you maybe know any other forums where I could ask about this? – kramer65 Aug 5 at 20:32

show 3 more comments0

Question

How to troubleshoot a BLDC motor?

Answer

Part A – TLDR

All my life I have been playing with toy DC motors, and I know them very well. However I have almost zero knowledge and experience on BLDC motors. I know that drones use BLDC motors, but actually I never owned any RC toys in my life, not to mention RC drones.

I also know quite a lot about 5V/12V regulated power supplies for toy motors, but I don’t know what is ESC, and I have never seen the real ESC thing in my life.

I need to introduce my sub newbie knowledge and experience on BLDC motor because I must warn the experienced RC guys that I am ignorant in RC, so bear with me talking stupid RC stuff. RC Ninjas can skip the following parts basic parts and start with the real BLDC thing.

But I would appreciate it very much if anyone can point out my misunderstanding on RC, ESC, and BLDC, so I can make corrections ASAP, before letting EE SE losing too much face, …

Part B – Googling and Wikiing on BLDC Motoers

So I wikied and sursprisingly found that BLDC is much more complicated than the stupid DC motor, because inside it there is a switching power supply providing AC current, and most amazingly is that there is a control loop driver controlling the speed and torque of the motor.

This is indeed exciting, because I am starting to learn some control engineering theory and practice. Now I can boast to my bad friends that I am not just an plain vanilla EE hobbyist, but also a computing and control hobbyist. So my bad Anono friends should from now on respect me much more than I deserve, …

/ to continue, …

References

(1) 38SRZ-S BLDC Motor 12V/24V 2000/3000/4000/5000 rpms with built in drive for DIY US40 – AliExpress

(2) BLDC (Brushless DC) Electric Motor – Wikipedia

/ to continue, …

Appendices

Appendix A – BLDC Motor Wiki Reading Log

(2) BLDC (Brushless DC) Electric Motor – Wikipedia

So I wikied and learnt a lot, and made a reading log, which is a summary of the introduction part of the wiki column.

A BLDC motor, also known as electronically commutated motor, and synchronous DC motors, are synchronous motors powered by DC current via an inverter or switching power supply which produces AC current to drive each phase of the motor via a closed loop controller. The controller provides pulses of current to the motor windings that control the speed and torque of the motor. This control system replaces the commutator (brushes) used in many conventional electric motors.

The construction of a brushless motor system is typically similar to a permanent magnet synchronous motor (PMSM), but can also be a switched reluctance motor, or an induction (asynchronous) motor. They may also use neodymium magnets and be outrunners (the stator is surrounded by the rotor), inrunners (the rotor is surrounded by the stator), or axial (the rotor and stator are flat and parallel).

The advantages of a brushless motor over brushed motors are high power-to-weight ratio, high speed, electronic control, and low maintenance. Brushless motors find applications in such places as computer peripherals (disk drives, printers), hand-held power tools, and vehicles ranging from model aircraft to automobiles, …

End of answershareimprove this answer  follow answered 52 mins agotlfong01add a comment

Return to Question