Hi all,
I’m testing the motor Leopard 5692 730KV. My unit is an older version (from 2 year ago, according with the manufacturer) which have a 6mm shaft. To be honest, I bought this due to lack of clear information from the listing (eBay).
I’m using a Mystery 200A ESC powered (temporary) by a 300W bench power supply (25.9V with 10Amax).
My experience from now, is as below:
- After start up, the motor is running at 2.5A without load.
- After a couple of minutes, the temperature in the surface get ~50C measured with a thermal camera.
Below some pictures during testing:
I’m concern with the temperature. A couple of questions:
- Which test you perform once you received a new motor?
- What is the operational temperature range of your motors (with and without load)?
@pacificmeister show a great picture showing the temperature (with other variables) during one of his testing (Custom Direct drive motor - #25 by pacificmeister - Propulsion System (Motor, Gears) - FOIL.zone). The graph show ~50C as the maximum temperature with different conditions as mine (with load!).
The circular carton box came broken around the shaft (that could be the reason of the temperature situation).
Thanks
Lao Hu
Hello,
Using a thermal camera may give out the wrong results a thermocouple must be used for more accurate results, this will be my first suggestion.
The temperature inside the motors are never a demanded situation, you should be able to test the motor fully, even under the load of maximum current, it should be durable.
The issue with the thermal cameras might be deceiving due to bearings, which also heat up during the rotation.
The motors in the industry often shut itself off after some temperature, the temperatures are shared by the manufacturers.
The boundary conditions will be also important. In our case we are pretty lucky, in case the motor is surrounded by a conductive material, the water will be acting as the perfect cooler.
To answer your question:
- If cheap, prototypes and tryouts. If not, using a safety coefficient and relying on it.
- Provided by the manufacturers and depends on many factors, the motor may be reliable but the cable might be burning at that moment.
I hope I was able to fulfill your answers, I am new in here but I have been dealing with some of these during the maintenance and malfunctions in our factory.
Best,
Akin
i had the same temp issue with my TPmotor, first test no load in my hand 3A i could not hold more then 1min, play with the esc setting, put 12°, now it has 8h of running, cooling in tube with water, no problem
i have read at the time that is ok to have some heat, specially with no load as long as it doesn’t goes to high and it will be i guess around 70°c for the magnet and that a way for tuning the timing (by checking the temp )
i think the leopard motor are given for 30000rpm so don’t go to high for the bearings, if you don’t have any vibrations or weird noise,your motor is ok and the shaft is pretty strong , cartoon broken isn’t a problem
Hi @Akincan_Akulker, @Alexandre, thanks very much for your feedback.
@Akincan_Akulker, I agree with you about the thermal camera. I just take the pictures as a reference. Definitively, will include thermocouple soon in the project. Once I get the manufacturer data, I will share here (currently, the website show a Download button with incorrect link).
For somebody without mechanical engineering knowledge, what you mean with the following sentence?
@Alexandre, exactly the same here, I could not hold in my hand. Definitively, the temperature is a indicator that everything go OK. According with your numbers, I still have hope to use that motor (and not returning to seller). I will try more setting as you suggested.
A safety coefficient means you are making sure you are within the limits.
Say the temperature provided by the manufacturer is about 70°C
If you have the safety coefficient about 1.5, the temperature you should be aiming not to go up from should be
70/1.5=46.666667
In strength of materials this is always considered as something the designer should be using.
The way this safety coefficient is picked is usually determined with the human error.
Where the human lives are thought, in example the diving cylinders are considered, the safety coefficient can go up to 15.
Where the safety coefficient is only used as a factor of being on the safe side mechanically the safety coefficient is picked by error & trial or due prior experiences.
I am in love with the thermal cameras by the way, it has helped me many times during my work. I was able to see that there was a problem inside an electrical panel, which has 1.3 MW, which was going to lead it to some explosion, I am not trying to be a dick when I am critisizing 
It usually helps when the temperature distribution is not homogeneous, it becomes way easier to diagnose with the thermal cameras.
Hi @Akincan_Akulker, thanks for your detailed explanation about the term safety coefficient. Probably, I used this term in electronic design and other contexts but didn’t conceptualise it.
I didn’t take your suggestion as bad, the contrary!!! For me (and many others as well), as much critics, better! Much more when we are in the design stage, where we could change many things easily
Update.
I was playing with the different options from the ESC Mystery 200A, including acceleration, pole settings (degree), and PWM. I remove backward function and set the voltage to 7S (25.9V).
- The acceleration works as expected
- The pole settings don’t seem to be a difference in the temperature. Probably, without load there is not too much to test. The setting allows 2 poles normal and 2 poles with more current.
- 8, 16 and 32K, all the same for the temperature situation
I’m waiting a new ESC (powerfull) to see if something change.
I’m designing a 48V battery pack, and the Mystery dont support more than 26V. The Leopard 730KV support up to 50V.
